Sports - Lower Extremity

Question 1

What are the arthroscopic hip portals and structures at risk?

[AAOS comprehensive review 2, 2014]

Answer 1

1. Anterior

• Lateral femoral cutaneous nerve
• Femoral nerve
• Femoral artery

2. Anterolateral
   * Superior gluteal nerve
3. Posterolateral
   * Sciatic nerve
4. Midanterior
   * Lateral femoral cutaneous nerves

Question 2

During hip arthroscopy, what nerve is at risk due to traction and the perineal post?

[AAOS comprehensive review 2, 2014]

Answer 2

Pudendal nerve

• Can result in:
  
  • Hypoaesthesia of the perineum, scrotum and glans penis
  • Erectile dysfunction
  • Urinary incontinence

Question 3

What are the indications for hip arthroscopy?

[Sports Health. 2017; 9(5): 402–413.]

Answer 3

1. Central compartment

• Labral tears
• Chondral pathology
• Ligamentum teres pathology
• Septic arthritis
• Loose bodies
  2. Peripheral compartment
• Femoroacetabular impingement
• Subspine impingement
• Synovial disorders
• Capsular disorders
• Psoas tendon disorders
  3. Peritrochanteric compartment
• Greater trochanteric pain syndrome
• External snapping hip/iliotibial band disorder

4. Deep gluteal space

• Ischiofemoral impingement
• Proximal hamstring disorders
• Sciatic nerve disorders

Question 4

What are the contraindications to hip arthroscopy?

[Sports Health. 2017; 9(5): 402–413.]

Answer 4

1. Advanced OA
2. Ankylosis
3. Acetabular and/or femoral dysplasia
4. Severe deformity
   * Retroversion, SCFE, Perthes
5. Obesity (relative)
6. Neurological injuries/disorders (relative)
   * Eg. pudendal neuralgia or peroneal or sciatic nerve palsy

Question 5

What are the most common complications following hip arthroscopy?

[Bone Joint J. 2017 Dec;99-B(12):1577-1583]

Answer 5

1. Nerve injury (0.9%)

• Pudendal > LFCN > sciatic > common peroneal > femoral
• Traction injuries include sciatic, common peroneal and femoral [Muscles Ligaments Tendons J. 2016 Jul-Sep; 6(3): 402–409.]
• Compression injuries include pudendal nerve
• Portal placement injuries include LFCN
  2. Iatrogenic injury (0.7%)
• Chondral > labral
  3. HO (0.6%)
  4. Adhesions (0.2%)
  5. Infection (0.2%)
• Superficial > deep
  6. Other
• DVT, perineal skin damage, hematoma, broken instrument, incomplete reshaping, femoral neck fracture, hip instability, iliopsoas tendinitis, AVN, ankle pain, arthrofibrosis, dislocation

Question 6

What is the most common major complication following hip arthroscopy?

[Bone Joint J. 2017 Dec;99-B(12):1577-1583]

Answer 6

Intra-abdominal fluid extravasation

Question 7

What is the innervation of the acetabular labrum?

[BMC Musculoskeletal Disorders 2014, 15:41]

Answer 7

Branch from nerve to quadratus femoris and obturator nerve

• Contains:
  
  • Free nerve endings for nociception
  • Nerve end organs (Pacini, Golgi, Ruffini corpuscles) for proprioception
• Higher concentration in:
  
  • Anterosuperior and postersuperior labrum
  • Articular side more so than the capsular side

Question 8

What is the blood supply to the acetabular labrum?

[J Bone Joint Surg Am. 2010 Nov 3;92(15):2570-5]

Answer 8

Periacetabular vascular ring

• Originates from
  
  • Superior and inferior gluteal vessels
  • Medial and lateral femoral circumflex arteries
  • Intrapelvic vascular system.

Question 9

What is the function of the hip labrum?

[Journal of Biomechanics 33 (2000) 953-960]

Answer 9

1. Deepens the acetabulum and extends the coverage of the femoral head
2. Contributes to a negative pressure vacuum effect which adds stability to the hip joint
   * Greater force required to distract joint
3. Provides a seal against fluid flow in and out of the intra-articular space enhancing lubrication mechanisms
   * Encapsulates the fluid in the joint
4. Limits the rate of fluid expression from the cartilage during loading which enhances the cartilages ability to carry load and limit stresses on the cartilage

Question 10

What is the Seldes classification of hip labral tears?

[Clin Orthop Relat Res. 2001 Jan;(382):232-40]

Answer 10

Type 1 – “Detachment”

• Detachment of the labrum from the articular hyaline cartilage at the transition zone

Type 2 – “Intrasubstance”

• One or more cleavage planes of variable depth within the substance of the labrum

Question 11

What are the causes of hip labral tears?

[J Am Acad Orthop Surg 2017;25:e53-e62]

Answer 11

1. Trauma
2. FAI
3. Dysplasia
4. Hip hypermobility/capsular laxity
5. Degeneration

Question 12

where are labral tears typically located

Answer 12

anterosuperior aspect of the acetabulum

Question 13

describe the decision making algorithm when considering labrum debridement vs repair vs reconstruction

Answer 13

1. stable torn labrum
   
   1. acetabuloplasty not needed - selective debridement
   2. acetabuloplasty needed - repair
2. unstable torn labrum
   
   1. viable tissue = repair
   2. nonviable tissue, young patient - reconstruction
   3. poor vascularity or advanced age - selective debridement
3. mostly calcified torn labrum
   
   1. advanced age - selective debridement
   2. young - reconstruction

Question 14

How can you classify damage to the ligamentum teres, labrum and articular cartilage during hip arthroscopy?

[J Am Acad Orthop Surg 2017;25:e53-e62]

Answer 14

1. Domb classification of ligamentum teres tears

• Grade 0 = No tear
• Grade 1 = <50% tear
• Grade 2 = >50% tear
• Grade 3 = 100% tear

2. Seldes Classification of labral tears

• Grade 1 - chondrolabral junction tear
• Grade 2 - intrasubstance tear

3. ALAD (acetabular labrum articular disruption) Classification

• Grade 1 - softening of the adjacent cartilage
• Grade 2 - early peel of cartilage
  
  • Carpet delamination
• Grade 3 - large flap of cartilage
• Grade 4 - loss of cartilage
  4. Outerbridge classification
• Grade 0 - normal cartilage
• Grade 1 - cartilage with softening and swelling
• Grade 2 - partial thickness defect with fissures on the surface that do not reach subchondral bone or exceed 1.5cm in diameter
• Grade 3 - fissuring to the level of the subchondral bone in an area with a diameter larger than 1.5cm
• Grade 4 - exposed subchondral bone

Question 15

Describe the decision making algorithm when considering arthroscopic labral debridement vs. repair vs. reconstruction

[J Am Acad Orthop Surg 2017;25:e53-e62]

Answer 15

1. Stable torn labrum

• Acetabuloplasty not needed = selective debridement
• Acetabuloplasty needed = repair

2. Unstable torn labrum

• Viable tissue = repair
• Nonviable tissue, young patient = reconstruction
• Poor vascularity or advanced age = selective debridement

3. Mostly calcified torn labrum

• Advanced age = selective debridement
• Young = reconstruction

Question 16

What are the 3 main types of FAI?

Answer 16

1. Cam impingement – femoral based abnormality
2. Pincer impingement – acetabular based abnormality
3. Combined/mixed-type

Question 17

What are the features of a cam-lesion?

Answer 17

1. Aspherical femoral head
2. Reduced head-neck offset
3. Characteristic ‘bump’ at the head-neck junction
4. Pistol grip deformity

Question 18

Where is the typical cam-lesion located?

[J Am Acad Orthop Surg 2013; 21(suppl 1):S20-S26]

Answer 18

Anterosuperior head-neck junction

Question 19

What are the features of the pincer-lesion?

[J Bone Joint Surg Am. 2013;95:82-92]

Answer 19

1. Global overcoverage
   * Coxa profunda, coxa protrusio
2. Focal overcoverage
   * Cephalad retroversion
3. Acetabular retroversion

Question 20

What femur orientation contributes to FAI – anteversion or retroversion?

Answer 20

Femoral retroversion

Question 21

What radiographs and radiographic findings are important in assessing FAI?

[DeLee & Drez’s, 2015]

Answer 21

1. Radiographic views
   
   1. AP pelvis
   2. cross-table latera
   3. 45 ° Dunn view
   4. False profile view
2. Signs of pincer-lesion
   
   1. Crossover sign
      
      1. i. Normally the anterior lip of the acetebulum lies medial to the posterior lip and converge at the superolateral
         aspect of the acetabulum. With retroversion the anterior lip proximally lies lateral to the posterior lip and
         distally lies medially creating the crossover sign
   2. Prominent ischial spine sign
      
      1. Normally the ischial spine is hidden behind the acetabulum, if it appears more prominent it indicates acetabular retroversion
   3. Posterior wall sign
      
      1. Posterior rim of the acetabulum lies medial to the center of rotation of the femoral head indicating
         retroversion
   4. Lateral center edge angle
      
      1. The lateral center edge angle is the angle formed by a vertical line and a line connecting the femoral head center with the lateral edge of the acetabulum.
      2. LCE >40 suggests pincer-lesion. (<25 indicates dysplasia)
   5. acetabular index angle
      
      1. abnormal = <0 (>10 indicates dysplasia)
   6. anterior and posterior wall indices
      
      1. to calculate the acetabular walls index, the best fit circle to the femoral head contour is drawn.
      2. radius of the femoral head is determined, distance from the medial edge of circle to the anterior (aw) and posterior (pw) walls along the femoral neck axis line is measure. anterior wall index (awi) and posterior wall index are calculated as aw/R and pw/r respectively
         
         1. normal awi - 0.41 (0.3-0.51); normal pwi = 0.91(0.81-1.14)
      3. abnormal = awi increased (anterior overcoverage, pwi increased (posterior overcoverage); awi + pwi increased (global overcoverage)
   7. os acetabulum
   8. anterior femoral neck cortical reaction
   9. posteroinferior joint space narrowing
      
      1. evident on false profile view, occurs as a result of countercoup lesion with pincer type deformities, poor prognostic sign
   10. Signs of cam-lesion [JAAOS 2013;21(suppl 1):S20-S26]
   11. Alpha angle
       
       1. A circle is placed over the femoral head. The alpha angle is formed by a line along the axis of the femoral
          neck and a line from the center of the femoral head to the point where the head diverges outside the circle.
       2. An alpha angle >50 degrees is associated with femoroacetabular impingement.
   12. Head-neck offset and offset ratio
       
       1. Based on a lateral view, a line parallel to the long axis of the femoral neck is drawn along the anterior femoral neck and second line along the anterior aspect of the femoral head. The distance between the two is the head neck offset (<8mm likely represents cam-lesion). The offset ratio is the distance between the two lines divided by the diameter of the femoral head (<0.17 likely represents cam-lesion)
   13. herniation pits

Question 22

What radiographic view best demonstrates the maximal CAM deformity?

[JAAOS 2013;21(suppl 1):S20-S26]

Answer 22

45° Dunn view

• patient is supine with the pelvis in neutral rotation
• the hip joint is flexed 90° and abducted 20° while the pelvis remains in neutral rotation

Question 23

What radiographic view best demonstrates the anterior CAM deformity?

[JAAOS 2013;21(suppl 1):S20-S26]

Answer 23

Cross table lateral and frog leg lateral

Question 24

What special tests should be performed during the physical exam for FAI?

[J Am Acad Orthop Surg 2013; 21(suppl 1):S16-S19]

Answer 24

1. Impingement test (FADIR)
   * With the hip at 90° of hip flexion the hip is internally rotated and adducted
2. Posterior impingement test
   * Hip extension combined with external rotation
3. Log roll test
4. Resisted hip flexion test
5. FABER

Question 25

Associated injuries in cam impingement include?

[Orthop Clin N Am 44 (2013) 575–589]

Answer 25

1. Labral detachment from the acetabular rim
2. Cartilage delamination (full and partial-thickness)
   * Deeper compared to peripheral cartilage delamination in pincer impingement

Question 26

Associated injuries in pincer impingement include?

[Orthop Clin N Am 44 (2013) 575–589]

Answer 26

1. Labral pathology
2. Peripheral cartilage delamination
3. Contracoup chondrolabral lesions in the posterior acetabulum
   * Due to anterior levering of the femur causing posterior shear

Question 27

when is surgery indicated for FAI

Answer 27

1. symptomatic FAI that fails conservative treatment
2. patients with a history and physical exam consistent with FAI with radiographic evidence of focal impingement (cam, pincer or both, labral tears or chondrolabral disruptions) and minimal to no arthritic changes are the best candidates

Question 28

advantages of open surgical hip dislocation and arthroscopy for the management of fAI

Answer 28

1. advantages of open surgical dislocation
   
   1. 360 ° access to femoral head and acetabulum
   2. optimal visualization for correction of deformity
   3. ability confirm sphericity with open templates
   4. treatment of extra-articualr and intra-articular deformity
   5. optimal visualization with open dynamic assessment
   6. ability to perform relative neck lengthening
2. advantages of hip arthroscopy
   
   1. minimally invasive
   2. outpatient procedure
   3. potentially reduced pain
   4. potentially faster rehab
   5. potential for reduced soft tissue injury

Question 29

disadvantages of open surgical hip dislocation and arthroscopy for the management of FAI

Answer 29

• disadvantages of open
  
  • trochanteric osteotomy and potential for symptomatic hardware/nonunion
  • increased blood loss
  • ligamentum teres disruption
  • potential for prolonged rehabilitation
  • risk of AVN
• disadvantages of hip arthroscopy
  
  • traction-related complications and nerve injury
  • steep learning curve
  • incomplete access and correction of deformity
  • inability to directly confirm restoration of sphericity and offset
  • iatrogenic chondral injury
  • fluid extravasation and thigh or abdominal compartment syndrome
  • portal complications (lateral femoral cutaneous nerve injury)

Question 30

relative indication for open surgical dislocation rather than arthroscopic

Answer 30

1. large cam deformity with significant posterior and posterolateral extension
2. associated femoral chondral defects
3. confirmed or suspected extra-articular ischiofemoral or trochanteric-pelvic impingement
4. protrusio and coxa profunda
5. secondary acetabular overcoverage due to cirumferential labral ossification
6. revision cases

Question 31

what are predictors of positive outcome following hip arthroscopy for FAI

Answer 31

• pain relief from preop intra-articular hip injections
• lower BMI (<24.5kg/m2)
• younger age
• male sex
• tonnis grade 0
• increased joint space

Question 32

predictors of negative outcomes following hip arthroscopy for FAI

Answer 32

• older age (>45 years)
• female sex
• longer duration of preop pain symptoms (>8 months)
• elevated BMI
• OA changes - increased Tonnis grade ≥1), increased Kellgren-Lawrence grade (>3)
• decreased joint space (≥2mm)
• chondral defects
• increased lateral center edge angle (LCEA)
• undergoing of labral debridement rather than labral repair

Question 33

What are the risk factors for femoral neck fracture after hip arthroscopy for FAI?

[J Hip Preserv Surg. 2017 Jan; 4(1): 9–17]

Answer 33

1. Femoral osteochondroplasty
2. Early WB
3. Resection depth 10-33% the width of the femoral neck
4. Increased age

Question 34

how is snapping hip classified?

Answer 34

• • extra-articular
    
    • external (most common)
      
      • cause posterior ITB or anterior gluteus maximums over the greater trochanter
        
        • when the hip is extended the ITB lies posterior to the greater trochanter and moves anterior over the trochanter when the hip is flexed
    • internal
      
      • cause - iliopsoas tendon over the iliopectineal eminence of the pelvis or femoral head
        
        • when the hip is flexed, abducted and externally rotated the iliopsoas lies lateral and moves medial with hip extension, adduction and internal rotation
      • other suspected causes
        
        • iliopsoas tendon over the lesser trochanter
        • iliopsoas tendon over THA acetabualr component
        • iliofemoral ligament over the femoral head
        • long head of the biceps over the ischium
        • accessory iliopsoas tendon slips
  • intra-articular
    
    • causes- labral tears, Ligamentum tears, loose bodies, subtle instability

Question 35

features on history may suggest an external, internal or intra-articular etiology

Answer 35

1. external - lateral snapping sensation, sensation that the hip dislocates
2. internal - anterior sensation of snapping, “ getting stuck” or locking often assciated with an audible snap
3. intra-articular - sensation of intermittent clicking or catching (rather than snapping)

note - snapping may be painless and may be reproducible by the patient

Question 36

what is the management of snapping hip

Answer 36

• first line - non op
• second line - open or arthroscopic release or lengthening of offending structure
  
  • external - open z-lengthening or release of ITB, open or arthroscopic release of the gluteus maximums tendon insertion on femur
  • internal - open or arthroscopic lengthening or release of iliopsoas tendon
  • intra-articular - arthroscopic debridement or repair of offending structure

Question 37

what comprises the proximal hamstring

Answer 37

• semimembranosus (arises from superolateral ischial tuberosity)
• semitendinosus (arises from the inferomedial ischial tuberosity)
• long head of the biceps femoris (arises from the inferomedial ischial tuberosity)

Question 38

2 man types of proximal hamstring injuries

Answer 38

• muscle belly tear
• acute avlsions (tendinous or osseous from ischial tuberosity)

Question 39

most common mechanism of proximal hamstring injuries

Answer 39

high speed running

Question 40

indications for imaging of suspected proximal hamstring injuries

Answer 40

1. concerning physical exam findings (ecchymosis or palpable defect)
2. failure to improve with conservative care

Question 41

what are the indications for nonop and op management or proximal hamstring injuries?

Answer 41

1. nonop
   
   1. acute hamstring strains, partial tears, and single tendon avulsions
2. op
   
   1. complete avulsion of all 3 tendons with retraction exceeding 2.5 cm
   2. avulsion fracture with displacement exceeding 1cm
   3. sciatic nerve involvement with paresthesia or pain in the posterior aspect of the thigh

Question 42

ways to control intraop bleeding during knee scope

Answer 42

increase pump pressure, reduce outflow suciton, add epi tofluid, controled hypotension, tourniquet, drive scope to bleeding source, cautery, TXA

Question 43

causes of post traumatic knee hemarthrosis

Question 44

causes of post-traumatic knee hemarthrosis

Answer 44

1. acl tear
2. pcl tear
3. mcl tear
4. patellar dislocation
5. OC fracture
6. fracture of tib plateau, distal femur or patella
7. tibial spine avulsion
8. emniscus tear
9. psterolateral corner injury (avulsion of pop tendon

Question 45

rate of recurrent dislocation after first time patellar dislocation

Answer 45

33%

Question 46

What percent chance exists to have a recurrent dislocation if a patient has had 2 prior patella dislocations?

Answer 46

50%

Question 47

What are the factors that contribute to patella stability?

[JAAOS 2011;19:8-16]

Answer 47

1. Osseous anatomy

• Trochlear groove
  
  • Most important stabilizer at flexion >30°
  • Height and slope of the lateral trochlear facet provides the primary resistance

2. Static stabilizers

• MPFL and medial patellotibial ligament
  
  • Most important in full extension when patella is not engaged in trochlea (between 0-30)
  • Function to guide the patella into the groove from 0-20° flexion
    3. Dynamic stabilizers
• VMO
  
  • More variable contribution to patella instability

Question 48

Describe the anatomy of the MPFL?

Answer 48

MPFL

summary
- femoral attachment
- center of attachment is between the medial epicondyle and adductor tubercle
- patella attachment
- proximal third of the medial patella

• Femoral attachment
  
  • Center of attachment is between the medial epicondyle and the adductor tubercle
• Patella attachment
  • 7.4mm anterior to a tangent to the posterior patellar cortical line and 5.4mm distal to the proximal edge of the articular surface of the patella
  • Located at the junction of the proximal 1/3 and distal 2/3
  • Encompasses 33% of the total length of the patella [JAAOS 2014;22:175-182]

Question 49

Describe the anatomy of the medial quadriceps tendon femoral ligament (MQTFL)

Answer 49

• Femoral attachment - between the adductor tubercle and medial epicondyle
• Insertion - deep layer of the quadriceps tendon

Question 50

What are risk factors for patellar instability?

[JAAOS 2011;19:8-16]

Answer 50

1. Unfavourable bone anatomy

• Trochlea dysplasia (shallow, flattened trochlea groove)
  
  • Seen in <2% of the general population but in 85% of recurrent patellar instability
• Patella alta
• Increased TT-TG distance
• Increased Q angle
• Lower extremity rotational malalignment
  
  • femoral anteversion +/- external tibial torsion
    
    2. Dynamic stabilizer imbalance
• ITB
  
  • Increased tension causes lateral patellar tracking
• VMO/VLO
  
  • Imbalance in strength can lead to instability

3. Incompetent static stabilizers
   * Generalized ligamentous laxity

Question 51

Where anatomically is the MPFL typically injured?

[JBJS 2016;98:417-27]

Answer 51

Femoral origin

Question 52

What is the classification of trochlear dysplasia?

[JAAOS 2011;19:8-16]

Answer 52

Dejour classification

• Type A = shallow
  
  • Radiographic findings = crossing sign
• Type B = flat
  
  • Radiographic findings = crossing sign, supratrochlear spur
• Type C = lateral convexity/medial hypoplasia
  
  • Radiographic findings = crossing sign, double contour sign
• Type D = cliff
  
  • Radiographic findings = crossing sign, double contour sign, supratrochlear spur

Question 53

What is the classification of patellar dysplasia based on the asymmetry of the medial and lateral patellar facets?
(Skeletal Radiology (2019) 48:859-869][Sports Med Arthrosc Rev 2019;27:154-160]

Answer 53

• Wiberg’s classification (modified by Baumgart] to include Type 4)
  
  • Type 1 - the facets are concave, symmetrical and roughly of equal size
  • Type 2 - the medial facet is distinctly smaller than the lateral facet. The lateral facet remains concave, but the medial facet is either flat or slightly convex
  • Type 3 - the medial facet is considerably smaller and convex. The angle subtended by the two facets is nearly 90°
  • Type 4 - no medial facet or median ridge

Question 54

Why is the patella more unstable (and thus more prone to dislocation) in knee extension rather than flexion?

[J Bone Joint Surg Am. 2008;90:2751-62]

Answer 54

1. Q-angle is greatest in knee extension
2. Lowest quadriceps and patellar tendon tension
   * Low posterior directed force
3. Patella disengages from the trochlear groove

Question 55

What are the physical examination findings in patellar instability?

[JAAOS 2018;26:429-439]

Answer 55

1. J sign

• Knee is actively brought from flexion to extension
• Positive = Patella demonstrates a sudden, exaggerated lateral deviation after it fully exits the trochlear groove in full extension
  
  • Indicates either trochlear dysplasia or patella alta

2. Moving patellar apprehension test

• Most sensitive and specific
• Part 1:
  
  • Knee held in full extension and the patella is manually translated laterally with the thumb
  • Knee is then flexed to 90^o and then brought back to full extension while the lateral force on the patella is maintained
  • Positive:
    
    • Patient orally expresses apprehension and may activate his or her quadriceps in response to apprehension
• Part 2:
  
  • Knee is started in full extension, brought to 90^o of flexion, and then back to full extension while the index finger is used to translate the patella medially
  • Positive:
    
    • Patient experiences no apprehension and allows free flexion and extension of the knee

3. Lateral patellar translation
   * Normal = Lateral translation of the patella should be ¼ to ½ the width of the patella

Question 56

What is the radiographic landmark of the femoral insertion of the MPFL called and where is it located?

[Orthop Clin N Am 46 (2015) 147–157]

Answer 56

1. Schottle point

• 1 mm anterior to the posterior cortex extension line
• 2.5 mm distal to the posterior origin of the medial femoral condyle
• Proximal to the level of the posterior point of the Blumensaat line

2. Stephens normalized dimensions [JAAOS 2014;22:175-182]

• If AP dimension of medial femoral condyle is 100%, MPFL attachment is:
  
  • 40% from posterior
  • 50% from distal
  • 60% from anterior

Question 57

What are radiographic features to assess for in patellar instability?

[Orthop Clin N Am 46 (2015) 147–157] [J Bone Joint Surg Am. 2008;90:2751-62] [JAAOS 2011;19:8-16] )

Answer 57

1. Patella alta

• Insall-Salvati ratio (normal = 0.8-1.2)
• Caton-Deschampe ratio (normal = 0.6-1.3)
• Blackburn-Peel ratio (normal = 0.5-1.0)
• Blumensaat’s line should extend to the inferior pole of the patella at 30° of knee flexion
  2. Trochlear dysplasia
• Signs on lateral radiograph include:
  
  • Normally, floor of the trochlea should not pass anterior to a line extended along the anterior femoral cortex
  • Crossing sign:
    
    • A line represented by the deepest part of the trochlear groove crossing the anterior aspect of the condyles
  • Supratrochlear spur/prominence
    • Extension of the trochlear groove above the projection of the anterior cortex of the femur
    • Measured as the distance between the anterior femoral cortex and most anterior point of the trochlear floor
      
      • Abnormal = >4mm
  • Double contour
• Signs on the skyline view
  
  • Sulcus angle
    
    • Measured from the highest point on the condyles to the lowest point in the intercondylar sulcus
    • Normal = 138 ± 6°
    • Abnormal = >145°
      
      • Indicates trochlear dysplasia
        3. Lateral patellar tilt/subluxation
• Assess on skyline/Merchant view

Question 58

What radiograph is superior for evaluating trochlear anatomy?

[JAAOS 2018;26:429-439]

Answer 58

Laurin radiograph

• Knee flexed only 20°
• Imaging beam directed from inferior to superior

***45° sunrise view does not visualize the proximal trochlear groove (may miss supratrochlear spur)

Question 59

What is the role of CT in assessing patellar instability?

[Orthop Clin N Am 46 (2015) 147–157] [JAAOS 2018;26:429-439]

Answer 59

Used to assess the tibial tubercle-trochlear groove distance

• Measured by taking a line perpendicular to a line tangential to the posterior femoral condyles through the deepest part of the trochlear groove and through the apex of the tibial tubercle
  
  • Distance between these 2 lines is defined as the TT-TG distance
• used to assess patellar maltracking
  
  • multistage Ct scan at various degrees of flexion
  • imaging at positions both less than and grater than 30 ° can be used to avoid missing maltracking that might be captured at only certain degrees of flexion

Question 60

What TT-TG distance is associated with patellar instability?

Answer 60

>20mm (average normal is 9mm)

• 10-15mm = normal
  
  • MPFL reconstruction is usually sufficient
• 15-20mm = gray zone
  
  • Consider bony reconstruction in addition to MPFL reconstuction
• >20mm = abnormal
  
  • MPFL reconstruction unlikely to be sufficient
  • Needs bony reconstruction in addition to MPFL

***NOTE: 20mm is a guideline and not a rule; MRI values may be less

Question 61

What is the role of MRI in assessing patellar instability? [Skeletal Radiology (2019) 48:859-869] [Insights into Imaging (2019) 10:65] |JAAOS 2018;26:429-439] |JBJS Am. 2008;90:2751-62][Sports Med Arthrose Rev 2016;24:44-49]

Answer 61

• Used to assess tibial tubercle - posterior cruciate ligament distance
  - May more accurately describe tibial tubercle lateralization (uses tibial reference points)
  - Measured by taking a line perpendicular to the dorsal tibial condylar line through the midpoint of the tibial tubercle and the medial border of the PCL. The distance between the two lines is defined as the TT-PCL distance
  - Abnormal = >20mm
• Detects acute soft tissue and bony injuries
  - Bone bruising - edema on lateral aspect of lateral femoral condyle and inferomedial patella
  - Cartilage damage - osteochondral fracture of the medial patellar facet or lateral trochlear ridge
  - MPFL damage
  - VMO injury
• Used to assess patellar tilt
  - Lateral patellofemoral angle
  - Angle formed between a line drawn along the lateral patellar facet and a line along the anterior most points of the medial and lateral femoral condyles
  - Normal = angle should be >8° with the opening laterally
  - Abnormal = angle <8° or medial opening
  - Patella tilt angle
  - Angle between the posterior condylar line and the maximal patella width line
• Used to assess trochlear dysplasia
  - Lateral trochlear inclination angle
  - Measured on the superior-most axial image showing trochlear cartilage.
  - It is the angle between the plane of the subchondral bone of the lateral trochlear facet, and the posterior femoral condylar line
  - Abnormal = angle of <11°
  - Trochlear depth
  - Trochlear depth = [a + b)/2] - c
  - Where, the maximum AP distance of the medial femoral condyle (a), lateral femoral condyle (b) and trochlear groove (c) as measured from a line parallel to the posterior femoral condyles
  - Facet asymmetry
  - Determined by calculating the percentage of the medial to the lateral femoral facet length
  - Asymmetry of < 40% suggests trochlear dysplasia

Question 62

What measurement may more accurately describe tibial tubercle lateralization than TT-TG?

[JAAOS 2018;26:429-439]

Answer 62

Tibial tubercle – posterior cruciate ligament distance

• Normal <24mm
• Both are tibial reference points
  
  • Not affected by knee rotation like TT-TG

Question 63

What MRI findings are consistent with patellar instability?

[J Bone Joint Surg Am.2008;90:2751-62][Sports Med Arthrosc Rev 2016;24:44–49)]

Answer 63

1. Bone bruising
   * Edema on lateral aspect of lateral femoral condyle and inferomedial patella
2. Cartilage damage
   * Osteochondral fracture of the medial patellar facet or lateral trochlear ridge
3. MPFL damage
4. VMO injury

Question 64

What is the treatment of choice for first-time patella dislocation?

[JBJS 2016;98:417-27]

Answer 64

Nonoperative treatment

• Bracing
• ROM
• Strengthening
• Gradual return to play

Question 65

What is the standard surgical approach in patient with chronic lateral patellar instability with at least 2 documented patellar dislocations?

[JAAOS 2014;22:175-182]

Answer 65

Anatomic MPFL reconstruction

• Miniopen technique
• Using a graft stronger than the native MPFL
  
  • Semi-T or gracilis
  • Compensates for the uncorrected predisposing patellar instability factors

Question 66

What is the ideal indication for an MPFL reconstruction?

[JAAOS 2014;22:175-182]

Answer 66

1. Recurrent lateral patellar dislocation
2. TT-TG distance <20 mm
3. Positive apprehension test until 30° of knee flexion
4. Caton-Deschamps index of <1.2
5. Normal trochlea or Dejour type A dysplasia

Question 67

What are the errors in femoral tunnel position for MPFL reconstruction and their implications?

[JAAOS 2014;22:175-182]

Answer 67

1. Too proximal

• Graft lax in extension and tight in flexion
• Clinically:
  
  • Anterior knee pain
  • Loss of flexion
  • Graft stretch and failure

2. Too distal

• Graft tight in extension and lax in flexion
• Clinically:
  
  • Extension lag

Question 68

Where is the MPFL graft typically passed between the patella and femur?

Answer 68

Between layer 2 (medial patellar retinaculum) and layer 3 (capsule)

Question 69

At what knee flexion should graft tensioning be performed for MPFL reconstruction? [Sports Med Arthrosc Rev 2019;27:136-1423

Answer 69

• ≥60 degrees of knee flexion
  
  • The key is setting the length at the degree of flexion at which the attachment sites are farthest apart so the graft will become more lax at other degrees of flexion

Question 70

Is the native MPFL isometric?

[JAAOS 2014;22:175-182]

Answer 70

The MPFL is nonisometric over the complete ROM

• Tight in extension, Lax in flexion

Question 71

How should the MPFL graft function after reconstruction?

[JAAOS 2014;22:175-182]

Answer 71

1. The ROM after MPFL graft fixation should be complete
2. The MPFL graft should be isometric from 0-30°
3. The MPFL graft should tighten in extension and be lax in flexion
4. There should be a good endpoint to lateral patellar translation from 0-30°
5. The MPFL should only tighten on lateral patellar translation
6. Should permit 1cm of lateral translation or the equivalent of two quadrants of lateral deviation with a firm end point

Question 72

What are the most common complications following MPFL reconstruction?

[JBJS 2016;98:417-27]

Answer 72

1. Recurrent apprehension
2. Arthrofibrosis
3. Pain
4. Clinical failure
5. Patellar fracture

Question 73

What is the redislocation rate following MPFL reconstruction?

[JAAOS 2018;26:429-439]

Answer 73

<10%

Question 74

What are the indications and contraindications for a tibial tubercle transfer in the setting of patellar instability?

[JAAOS 2018;26:429-439]

Answer 74

Indications:

• TT-TG >20mm (measured on CT)
• High TT-PCL distance (>24mm)
• Caton-Deschamp ratio >1.2

Contraindications [JBJS 2016;98:417-27]

• Open tibial apophysis
  
  • Causes growth arrest and recurvatum
• Medial dislocations
• Patellofemoral OA of the proximal and medial facets

Question 75

What is the postoperative goal TT-TG after tibial tubercle transfer for patellar instability?

Answer 75

1. 10mm [JAAOS 2018;26:429-439]
2. 9-15mm [JBJS 2016;98:417-27]

Question 76

What is the main complication following tibial tubercle transfer for patellar instability?

[JBJS 2016;98:417-27]

Answer 76

Symptomatic hardware

Question 77

In the presence of trochlear dysplasia what is the recommended treatment for patellar instability?

[JAAOS 2011;19:8-16]

Answer 77

1. First-line

• Procedures to address associated factors rather than trochleoplasty
  
  • TT-TG and patella height normal = MPFL reconstruction
  • TT-TG >20mm = tibial tubercle transfer or femoral derotation osteotomy
    2. Second-line
• Trochleoplasty
  
  • Involves reshaping the trochlea by deepening the groove by removing subchondral bone and impacting the overlying catilage into the defect
  • Indications:
    • High-grade trochlear dysplasia (where other options won’t provide stability) and salvage situations

Question 78

What type of trochlea according to the Dejour classification is most likely to benefit from a trochleoplasty?

[JAAOS 2018;26:429-439]

Answer 78

Type B and D

• Both have supratrochlear spurs – tend to displace the patella laterally

Question 79

What are the indications and contraindications for trochleoplasty?

[JAAOS 2018;26:429-439]

Answer 79

• Indications
  
  • dejour tpe B or D trochlear dysplasia
  • Supratrochlear spur height > 5mm
  • Presence of J-sign
• Contraindications
  
  • Dejour type A or C trochlear dysplasia
  • Advanced patellofemoral OA
  • Open physes

Question 80

What are the main goals of sulcus-deepening trochleoplasty? [Sports Med Arthrosc Rev 2019;27:161-168]

Answer 80

• Eliminating the supratrochlear spur
• Deepening the trochlear sulcus
• Lateralizing the trochlear sulcus (effectively decreases the TT-TG distance)

Question 81

What are the indications for tibial tubercle osteotomy (distal realignment procedures)?

[Clin Sports Med 33 (2014) 517–530]

Answer 81

1. Recurrent patella instability if

• Skeletally mature
  
  • Proximal tibia and tibial tubercle physis closed
• TT-TG >15
• Caton-Deschamps >1.2

2. Unload focal patella cartilage lesions

• Without cartilage resurfacing for lateral or distal lesions
• With cartilage resurfacing for central or medial lesions

3. Isolated lateral patellofemoral compression, tilt or overload in patients who fail lateral release

Question 82

What are contraindications for TTO?

[Clin Sports Med 33 (2014) 517–530] [AJSM 2014; 42(8): 2006)

Answer 82

1. Skeletally immature
2. Medial patellar subluxation/dislocation
3. Diffuse patellofemoral arthrosis
4. Smoking

Question 83

What are the types of TTOs?

[Clin Sports Med 33 (2014) 517–530]

Answer 83

1. Medialization (Elmslie-Trillat procedure)

• Reduces the TT-TG
• Decreases pressure on lateral facet
• Amount of medialization is limited by the amount of bony contact available

2. Anterior transfer (Maquet)

• Goal is to reduce patellofemoral contact pressures
• Transfers the contact forces from distal to proximal patella
• Requires allograft or autograft bone block
• Not routinely done
  • Anteriorization usually combined with medialization
• Can be indicated for unloading large distal patellar chondral lesions, bipolar kissing lesions or arthritis in setting of normal TT-TG
  3. Distalization
• Indications:
  
  • Caton-Deschamps or Insall-Salvati >1.2 (usually >1.4)
• Rarely done in isolation
  
  • Usually combined multiplanar osteotomy
• Caution with overdistalization which can limit knee flexion

4. Anteromedialization (Fulkerson)

• The amount of anteriorization and medialization is determined by the obliquity of the osteotomy
  
  • Increased obliquity [A-P] = increased anteriorization
  • With a constant anteriorization of 15mm: [AJSM 2014; 42(8): 2006)
    • 60° slope creates ~9mm of medialization
    • 45° slope creates ~15mm of medialization
• Advantages:
  
  • Preserves extensor mechanism
  • Large surface for bone healing
  • Ability to place multiple screws
  • Multiplanar adjustments
  • Early ROM
• Disadvantages
  
  • Does not address incompetent MPFL
  • Hardware irritation
  • Potential NV injury
  • Increased medial PF contact pressures
  • Delayed union/nonunion
  • Cannot perform in skeletally immature

Question 84

What are the complications associated with TTO?

[Clin Sports Med 33 (2014) 517–530][AJSM 2014; 42(8): 2006)

Answer 84

1. Hardware irritation (50% require removal)
2. Nonunion/delayed union
3. Compartment syndrome
4. Anterior tibial artery injury
5. Deep peroneal injury
6. Infection
7. DVT
8. Medial patellar instability
9. Fracture of tubercle
10. Fracture of proximal tibia
11. Skin necrosis

Question 85

What is the etiology of ACL tears?

[J Am Acad Orthop Surg 2013;21:41-50]

Answer 85

1. Noncontact injuries (70%)
   * Most commonly a deceleration event and change in direction with a planted foot (cutting maneuver)
2. Trauma (30%)

Question 86

What are the risk factors for an ACL tear?

[J Am Acad Orthop Surg 2013;21:41-50]

Answer 86

1. Female sex
2. Increased friction and shoe-playing surface interface (eg. cleats)
3. Notch stenosis
4. Increased posterior tibial slope
5. Increased Q-angle
6. Smaller ACL
7. Increased quadriceps to hamstring strength
8. Poor landing position
   * Erect, hips adducted/internally rotated, knee relatively extended/valgus, tibia externally rotated

Question 87

What factors make females 2-8x more likely than male athletes to sustain an ACL injury?

[JAAOS 2013;21:41-50]

Answer 87

1. Increased Q angle
2. Notch stenosis
3. Smaller ACL
4. Increased quadriceps to hamstring strength and recruitment ratio
5. Poor landing position
6. Others:

• Increased medial posterior tibial slope
• Hormonal factors
• Increased generalized ligamentous laxit
• Increased knee laxity

Question 88

P/E special tests for ACL tears

Answer 88

• anterior drawer test
  
  • patient supine, hip flexed at 45° knee flexed at 90°, the foot is fixed to the table, anterior force is applied to proximal tibia while palpating the joint line for anterior translation
  • positive = increased anterior tibial translation
• lachman test
  
  • with the patient supine and the knee flexed 20-30°, the femur is stabilized laterally with one hand and the other hand grasps the tibia medially and translates the tibia anteriorly
  • positive = increased anterior tibial translation
  • grading
    
    • anterior translation of affected knee compared to contralateral knee
      
      • Grade I = >1-5mm
      • Grade II = 6-10mm
      • Grade III = >10mm
    • pivot shift test
      
      • with the patient supine one hand grasps the heel and the other hand is placed over the fibular head and applies a valgus force while taking the knee form extension into flexion
      • positive = reduction of a subluxated tibia at 30-40 ° sensed as a clunk or a glide
      • Grading
        
        • I = glide
        • II = clunk
        • III = gross reduction

Question 89

What are the indications for ACL reconstruction?

[AAOS comprehensive review 2, 2014]

Answer 89

1. Athletes who perform cutting and pivoting sports
2. High demand occupations (eg. police or military)
3. High risk occupations (eg. firefighter)
4. Recurrent instability

Question 90

What are indications for nonoperative management of ACL injuries?

[AAOS comprehensive review 2, 2014]

Answer 90

1. Low physical demand patients
2. Older age
3. Advanced osteoarthritis
4. Patients unwilling or unable to comply with postoperative rehab

Question 91

What radiographic features would suggest a possible ACL injury (4)?

Answer 91

1. Effusion
2. Segond fracture
3. Tibial tubercle avulsion
4. Lateral femoral notch sign/deep sulcus sign

Question 92

What are the MRI findings to support the diagnosis of an ACL tear?

Answer 92

1. Direct

• Fibre discontinuity
• Increased signal intensity
• Abnormal orientation
• ‘Empty notch sign’ (chronic)
  2. Indirect
• Bone bruises
• Anterior tibial translation
• PCL buckling (reduced PCL angle)
• Uncovering of the posterior horn of the lateral meniscus

Question 93

What is the collagen composition of the ACL?

[World J Orthop 2015,18;6(2):252-262]

Answer 93

Type I – 90%

Type III – 10%

Question 94

What are the bundles of the ACL and what are their function?

[Sports Med Arthrosc Rev 2010;18:27–32] [Clin Sports Med 36 (2017) 9–23]

Answer 94

Bundle named based on tibial insertion

• Anteromedial
  
  • Main contributor to AP stability
  • Taught in flexion, relaxed in extension
• Posterolateral
  
  • Main contributor to rotational stability
  • Taught in extension, relaxed in flexion

Question 95

Describe the femoral insertion of the ACL?

Answer 95

Medial wall of the lateral femoral condyle

• Posterior to the resident’s ridge (lateral intercondylar ridge)
• Lateral bifurcate ridge separating the AM from the PL bundle
  
  • AM bundle superior and PL bundle is inferior to bifurcate ridge

Question 96

What are the arthroscopic landmarks to determine the centre of the ACL femoral footprint (single bundle technique)?

[JAAOS 2016;24:443-454]

Answer 96

1. 8mm anterior to the posterior articular margin of the lateral femoral condyle
2. 1.7mm proximal to the bifurcate ridge

Question 97

How do you landmark the ACL femoral footprint using fluoroscopy?

[JAAOS 2016;24:443-454]

Answer 97

For single-bundle reconstruction:

• Center of the femoral footprint can be referenced on a grid using the Blumensaat line
• 28% of the distance from proximal to distal
• 34% posterior to the Blumensaat line

Question 98

Describe the tibial insertion of the ACL?

[Clin Sports Med 36 (2017) 9–23]

Answer 98

Broad insertion anterior and between the medial and lateral tibial spines

• AM bundle located more anterior and medial
• PL bundle located more posterior and lateral

Question 99

What are the arthroscopic landmarks to determine the centre of the ACL tibial footprint (single bundle technique)?

[JAAOS 2016;24:443-454]

Answer 99

1. 9mm posterior to the posterior edge of the intermeniscal ligament
2. 5mm anterior to the peak of the medial tibial spine
3. Midway between the medial and lateral tibial spines in the coronal plane

***Note: not recommended to use the lateral meniscus as a reference as the anterior horn insertion is variable

• If used the centre of the footprint is posterior and medial to the anterior insertion

Question 100

How do you landmark the ACL tibial footprint using fluoroscopy?

[JAAOS 2016;24:443-454]

Answer 100

1. 43% of the distance anterior to posterior of the midsagittal tibial diameter
2. 51% medial to lateral on the AP view

Question 101

On a postoperative radiograph, what is the ideal ACL tibial tunnel position and femoral tunnel position?

[Skeletal Radiol (2013) 42:1489–1500]

Answer 101

1. Lateral

• Anterior wall of the tibial tunnel should be posterior to a line extended along Blumensaat’s line with knee in extension
• No part of the femoral tunnel should intersect Blumensaat’s line

2. AP

• Angle between the femoral anatomical axis and the femoral tunnel ideally is 39°
  
  • ≤17° is associated with rotational instability

Question 102

Describe the relationship of the ACL AM to the PL bundle in extension compared to flexion?

[World J Orthop 2015,18;6(2):252-262]

Answer 102

1. Extension

• Femoral insertions are vertical (AM above PL)
• Bundles are parallel
• PL bundle is tight and AM bundle is relaxed

2. Flexion

• Femoral insertions are horizontal (AM posterior to PL)
• Bundles are crossed
• PL bundle is relaxed and AM bundle is tight

Question 103

What is the surgical terminology used when describing the ACL femoral tunnel placement?

Answer 103

With knee in flexion as occurs during surgery:

• Shallow/deep (A-P)
• High/low (superior-inferior)

Question 104

Is the native ACL isometric?

[World J Orthop 2015,18;6(2):252-262]

Answer 104

No

• “Isometry in ACL does not exist as there is no one point on femur that maintains a fixed distance from a single point on the tibia during the range of motion of the knee.”

Question 105

What is the rational for isometric ACL graft placement?

[World J Orthop 2015,18;6(2):252-262]

Answer 105

1. An isometric graft avoids changes in graft length and tension during knee flexion and extension which avoids graft failure by overstretching
2. Downside is it results in a more vertical graft which is not as effective in controlling rotation
3. Isometric point on the femoral side is high in the notch and posterior

Question 106

What clock position is thought to be optimal for the ACL femoral tunnel to achieve graft isometry?

[World J Orthop 2015,18;6(2):252-262]

Answer 106

11 o’clock (right) and 1 o’clock (left)

• Apex of the notch represented by 12 o’clock

***NOTE – changing the position to 10 o’clock (right) or 2 o’clock (left) improves the rotational stability

• Graft becomes less vertical

Question 107

What is the blood supply of the ACL?

[Clin J Sport Med 2012;22:349–355]

Answer 107

1. Primary – middle genicular artery
2. Secondary – inferomedial and inferolateral genicular arteries

Question 108

What is the innervation of the ACL?

[Clin Sports Med 36 (2017) 9–23]

Answer 108

Branches of the tibial nerve

Question 109

What is the average length of the native ACL?

[World J Orthop 2015,18;6(2):252-262]

Answer 109

33mm

Question 110

What is a cyclop lesion (in context of ACL)?

Answer 110

Focal nodule of fibrous tissue sitting in the intercondylar notch anterior to the reconstructed ACL

• Significance:
  
  • Limits complete knee extension due to intercondylar notch impingement

Question 111

With an ACL injury, what is the typical bone bruises identified on MRI and what is their significance?

[AAOS comprehensive review 2, 2014][Sports Med Arthrosc Rev 2016;24:44–49]

Answer 111

1. Anterolateral femoral condyle (sulcus terminalis) and posterolateral tibial plateau (“kissing lesion”)
2. Compared to those without bone bruises:

• Protracted clinical recovery
• Greater effusions and pain scores
• Slower return of motion

Question 112

What is the most common meniscus injured in the acute vs. chronic ACL deficient knee?

[J Am Acad Orthop Surg 2013;21:204-213]

Answer 112

1. Acute ACL injury – lateral meniscus tear
2. Chronic ACL injury – medial meniscus tear

Question 113

What are graft options for ACL reconstruction?

Answer 113

1. Hamstring autograft
2. Bone-patellar-bone autograft
3. Quadriceps tendon autograft
4. Allograft

Question 114

Which ACL graft has the greatest strength and stiffness?

Answer 114

Quadrupled-strand hamstring graft

Question 115

What ACL graft size diameter (mm) has been shown to decrease failure rates?

[Arthroscopy 2014 Jul;30(7):882-90]

Answer 115

8mm

• “Quadrupled-strand hamstring autograft with a diameter equal to or larger than 8 mm decreases failure rates. Grafts larger than 8 mm were found to provide a protective effect in patients aged younger than 20 years, a group identified to be at increased risk of failure”

Question 116

What is the concern with ACL grafts that are too large?

[JBJS 2017;99:438-45]

Answer 116

Impingement of the graft on the roof and PCL

Question 117

When selecting an interference screw for ACL soft tissue grafts, how can you increase the fixation strength?

[JBJS 2017;99:438-45]

Answer 117

Increase screw length or diameter

Question 118

What is the general recommendation for notchplasty during ACL reconstruction?

[JBJS 2017;99:438-45]

Answer 118

Notchplasty is not recommended during ACL reconstruction

• Smaller intercondylar notch dimensions are not associated with ACL graft failure

Question 119

What are the cons of using an ACL BTB autograft?

[Clin J Sport Med 2012;22:349–355] [DeLee & Drez’s, 2015]

Answer 119

1. Anterior knee pain
2. Loss of sensation
3. Patellar fracture
4. Inferior patellar contracture
5. Patellar tendon rupture
6. Quadriceps weakness
7. increaserd risk of patellofemoral OA
8. kneeling pain

Question 120

What is one way to increase the strength of an ACL BTB autograft?

[JBJS 2017;99:438-45]

Answer 120

Twisting the graft

• “Twisting the graft by 90° increased the ultimate strength by 30%”

Question 121

What portion of the ACL BTB graft is the strongest and stiffest – medial, central or lateral 1/3?

[JBJS 2017;99:438-45]

Answer 121

Central 1/3

Question 122

What are two ways to manage graft tunnel mismatch when an ACL BTB graft is too long?

[JBJS 2017;99:438-45]

Answer 122

1. Rotate the graft

• Based on rotation from the proximal (patellar) end
• External rotation has been shown to more significantly reduce graft length compared with internal rotation
  
  • Shortening of 25% at 630° external rotation

2. Single bone plug
   * Proximal patellar tendon is removed from patella without a bone plug

Question 123

What are the cons of using hamstring autograft for ACL reconstruction?

[Clin J Sport Med 2012;22:349–355]

Answer 123

1. Decreased hamstring strength and endurance
2. Difficult to harvest due to variable graft length and diameter
3. higher failure rate than BTB

Question 124

What are the advantages and disadvantages of allograft for ACL reconstruction?

[Clin J Sport Med 2012;22:349–355]

Answer 124

Advantages

• Avoid donor-site morbidity
• Reduced operative time
• Availability of larger grafts
• Superior cosmesis
• Possibility for multiple ligament reconstructions

Disadvantages

• Delayed graft incorporation
• Disease transmission
• Potential immune reactions
• Altered mechanical properties caused by sterilization
• Cost of the allograft

Question 125

Which ACL graft, hamstring or BTB, shows greater migration of osseus fixation and graft stretching?

[JBJS 2017;99:438-45]

Answer 125

Hamstring

Question 126

What are the main techniques for ACL reconstruction with respect to femoral tunnel preparation?

Answer 126

1. Anteromedial
2. Transtibial
3. Outside-in
4. all inside

Question 127

which ACL reconstruction technique often results in a nonanatomic femoral tunnel position

Answer 127

transtibial

Question 128

features of an all-inside technique for ACL reconstruction

Answer 128

1. sockets are drilled from inside out
2. graft is introduced into the knee from an arthroscopic portal rather than a tunnel

Question 129

advantages of an all-inside technique for ACL reconstruction

Answer 129

• improved cosmesis
• preserves bone
• reduced postop pain and swelling
• retrograde drilling of the femoral tunnel results in longer intraosseous distances
• quadrupled semitendinosus graft can be utilized which preserves the gracilis tendon
  
  • flexion strength is improved postop
  • gracilis can be used for other ligament reconstruction or revision ACL

Question 131

Which ACL reconstruction technique results in a more anatomic femoral tunnel position?

[World J Orthop 2015,18;6(2):252-262]

Answer 131

Anteromedial portal technique

Question 132

What is the clinical difference between single and double bundle ACL reconstruction?

[JBJS 2017;99:438-45] [Arthroscopy. 2015 Jun;31(6):1185-96]

Answer 132

No significant difference

• DB ACL-R provides significantly better knee stability (by KT arthrometry and pivot-shift testing) than SB ACL-R but no advantages in clinical outcomes or risk of graft failure

Question 133

What is the most common cause of primary ACL reconstruction failures?

[Sport Health 2014; 6(6):504]

Answer 133

Technical error

• Improper tunnel placement outside the native femoral and tibial ACL footprints

Question 134

What is the consequence of improper ACL tunnel placement on the femoral and tibial side?

Answer 134

1. Errors in femoral tunnel placement

• Too anterior
  
  • Excessive graft tensioning with flexion leading to loss of knee flexion or stretching of the graft
• Too posterior
  • Excessive graft tension in extension with laxity in flexion
• Too vertical
  
  • Inadequate rotational stability
    
    2. Errors in tibial tunnel placement
• Too anterior
  
  • Notch impingment and loss of extension
• Too posterior
  
  • PCL impingement and loss of flexion
• Too medial/lateral
  
  • Notch impingement and iatrogenic tibial plateau cartilage damage

Question 135

What evidence is there to support functional bracing post-ACL reconstruction?

[Knee Surg Sports Traumatol Arthrosc (2014) 22:1131–1141]

Answer 135

1. No brace has been validated in the literature to improve patient outcomes or reduce the risk of reinjury
2. Functional bracing improves proprioception, feelings of stability and confidence
3. Functional bracing reduces anterior tibial translation (up to 140N) and rotational torques (up to 8Nm)

Question 136

What are potential risk factors for the development of posttraumatic OA following ACL injury?

[Clin Sports Med 32 (2013) 1–12]

Answer 136

1. Meniscus injury
   * Status of the meniscus may be the most important factor for the development of OA regardless of nonoperative or ACL reconstruction
2. BMI
   * Correlation between BMI and development of OA
3. Chondral injury
   * May occur at time of injury or secondary to instability
4. Graft choice
   * BTB graft may have an increased prevalence of OA compared to hamstring graft
5. Timing of ACL reconstruction
   * Acute surgery may prevent secondary meniscal and chondral injuries

Question 137

At a minimum 10 year followup, what is the risk of developing posttraumatic OA after ACL injury treated nonoperative compared to ACL reconstruction?

[AJSM 2014; 42(9):2242]

Answer 137

1. The relative risk of developing OA after an ACL injury (regardless of associated injuries or treatment) is 3.89 compared to the contralateral uninjured knee
   * i.e. The ACL injured knee is almost 4x more likely to develop OA compared to the contralateral knee
2. The relative risk of developing OA after ACL reconstruction (regardless of meniscal injury) is 3.62 compared to the contralateral knee
3. The relative risk of developing OA treated nonoperative (regardless of meniscal injury) is 4.98 compared to the contralateral knee
4. Therefore, ACL reconstruction reduces the risk of developing OA compared to nonoperative treatment

Question 138

investigation recommended to assist in selecting appropriate surgical technique

Answer 138

wrist/hand xray - determines Sanders bone age

Question 139

risk of delaying ACLR or treating nonop in skeletally immature patients

Answer 139

• meniscal and chondral injury
• psychological effects resulting from activity restrictions

Question 140

RF for physeal injury in ACL reconstruction

Answer 140

• proportion of physis violation
  
  • <5% = low risk
• location of tunnel within physis
  
  • central = low risk of arrest(compared to peripheral)
• orientation of tunnel
  
  • vertical tunnel = low risk due to lower proportion of physis affected

Question 141

indications for nonop and operative intervention

Answer 141

• nonop
  
  • partial tear
  • normal or near normal physical exam
• operative
  
  • older patients
  • instability on physical exam

Question 142

surgical ACL reconstruction options available in skeletally immature patient

Answer 142

1. intra-articular extraphyseal
2. all-epiphyseal
3. partial transphyseal
4. physeal-respecting transphyseal
5. traditional transphyseal

Question 143

what ACL reconstruction options should be considered based on age

Answer 143

1. bone age ≤8
   
   1. intra-articular extraphyseal
2. bone age >8 and ≥ 2 years of growth remaining
   
   1. all-epiphyseal
3. <2 years of growth remaining (approaching skeletal maturity)
   
   1. partial transphyseal
   2. physeal-respecting transphyseal
4. skeletally mature
   
   1. traditional transphyseal

Question 144

intra-articular extraphyseal technique

Answer 144

• IT band reconstruction (Kocher technique)
  
  1. nonanatomic
  2. midsubstance slip of the iliotibial band is looped posterolaterally over the lateral femoral condyle then passed through the intercondylar region, through the joint, and under the intermeniscal ligament to form a new ACL. A trough is placed under the intermeniscal ligament to allow for more anatomic graft placement without causing direct physeal injury
  3. proximally, autogenous graft is sutured to the periosteum of the lateral femoral condyle at the insertion of the intermuscular septum. Distal to the joint, the graft is sutured to periosteal flaps at the proximal anterior tibia with the use of heavy nonabsorbable sutures

Question 145

what is the all epiphyseal technique

Answer 145

• tunnels are drilled in femoral and tibial epiphysis under fluoro visualization
• hamstring autograft is fixed on the femoral side with a cortical button or interference screw
• fixation on the tibial side can be with a cortical button or interference screw or distally over a post

Question 146

partial transphyseal (hybrid technique)

Answer 146

1. all epiphyseal femoral tunnel
   
   1. avoidance is suggested due to
      
      1. more longitudinal growth from the distal femoral physis compared to the proximal tibial physis
      2. femoral tunnel is more peripheral - higher risk of angular deformity
2. central transphyseal tibial tunnel

Question 147

what is transphyseal technique

Answer 147

femoral and tibial tunnels are transphyseal

Question 148

practices that can be used to avoid physeal injury in transphyseal ACL reconstruction technique

Answer 148

1. vertical tunnel
2. tunnel diameter ≤ 8mm
3. central tunnels (avoid peripheral tunnels)
4. avoid perichondral ring
5. hardware and bone should not be placed across the physes
6. soft tissue grafts preferred
7. heat necrosis should be avoided by hand drilling or slow drilling speeds

Question 149

recommended graft choice for peds ACL

Answer 149

1. all soft tissue and autograft
2. note - if BTB graft is used avoid placement of bone at the level of the physis, which may increase risk of bony bridging across the physis

Question 150

risk of graft failure and retear in skeletally immature ACL reconstruction

Answer 150

15-25%

Question 151

What is the etiology of tunnel widening following ACL reconstruction?

[JAAOS 2010;18:695-706]

Answer 151

1. Mechanical factors

• Mechanical theory suggests that graft motion within the tunnel can abrade the tunnel edge producing widening
• Graft position
  
  • Malpositioned tunnels can lead to increased graft forces being transmitted to the graft-bone interface
  • Eg. anterior tibial tunnel leads to notch impingement and increased force on the graft
• Fixation method
  
  • Increased distance between fixation points leads to decreased stiffness and increased graft motion
  • Bungee cord effect
    
    • Longitudinal graft motion with elongation and retraction of the graft in the tunnel
    • Seen with suspensory fixation compared to aperture fixation
  • Windshield wiper effect
    
    • Transverse graft motion within the tunnel
    • Seen with fixation not at the aperture of the tunnel
      2. Biological factors
• Graft sterilization
  
  • Ethylene oxide sterilization associated with tunnel widening
• Inflammatroy cytokines
  • May increase osteoclastic activity
• Implant material
  
  • Bioabsorbable screws may have greater tunnel widening compared to metal screws
• Graft type
  
  • Hamstring autograft shows greater tunnel widening compared to BTB
• Graft donor
  
  • May be more widening with allograft compared to autograft
• Synovial fluid propagation
  
  • Influx of synovial fluid may delay healing

Question 152

What is acceptable tunnel widening in the first 6-12 months post ACL reconstuction?

[Skeletal Radiol (2013) 42:1489–1500]

Answer 152

2mm

Question 153

What radiographic features suggest tunnel widening post ACL reconstruction?

[Skeletal Radiol (2013) 42:1489–1500]

Answer 153

1. Widening >2mm
2. Loss of parallel walls (cone-shaped)

Question 154

What is the best imaging modality for assessing tunnel widening post ACL reconstruction?

[Skeletal Radiol (2013) 42:1489–1500]

Answer 154

CT

Question 155

What are the clinical implications of tunnel widening?

[JAAOS 2010;18:695-706]

Answer 155

1. No implication to clinical outcome
2. Significant if ACL revision surgery undertaken

Question 156

What are the suggested options for graft choice and implant during revision ACL recon in setting of tunnel widening?

[JAAOS 2010;18:695-706]

Answer 156

1. Allograft achilles tendon
   * If autograft was used for primary
2. Autograft BTB
   * If allograft was used for primary
3. Implant – aperature fixation with metallic screw

Question 157

What are the options to manage tunnel widening during ACL revision surgery?

[JAAOS 2010;18:695-706]

Answer 157

1. Single stage (<100% widening)

• Option in good bone stock
  
  • Divergent tunnel (funnel) technique
• Options in poor bone stock
  
  • Stacked screw
  • Matchstick (bullet) graft
  • Large bone plug graft
    
    2. Two-stage (>100% widening or tunnel diameter >15mm) [Skeletal Radiol (2017) 46:161–169]
• Primary bone graft with delayed reconstruction
  
  • 3-4 months post-bone grafting

Question 158

What is the most common organism causing septic arthritis post-ACL reconstruction?

[J Am Acad Orthop Surg 2013;21:647-656]

Answer 158

Staph aureus (31%)

Question 159

In cases of ACL graft contamination (‘dropped graft’) how should you proceed?

[J Am Acad Orthop Surg 2013;21:647-656]

Answer 159

Cleanse with NS, followed by chlorhexidine then NS

Question 160

What is the recommended management of septic arthritis post-ACL reconstruction?

[J Am Acad Orthop Surg 2013;21:647-656]

Answer 160

1. Perform arthrocentesis and blood culture prior to antibiotics
   * Septic arthritis suggested if cell count >100,000 (may be as low as 25,000) and cell differential >90 PMNs
2. Start broad-spectrum antibiotics
   * Can delay until after intra-operative cultures are sent if patient is stable
3. Immediate arthroscopic I&D
   * Assess graft integrity and viability (probe graft, pivot-shift)
   * Send intraoperative synovial fluid and synovium samples for culture
   * Extensive lavage and synovectomy
   * Graft removal is recommended in the setting of:
   
   • Significant intrasubstance degeneration
   • Gross evidence of infection compromising the graft
   • Nonfunctional graft as determined by inadequate graft tension or significant pivot shift performed under anesthesia
     * A closed-suction drainage system is typically used postoperatively to assist in wound drainage and is kept in place until there is minimal output
     * Immobilize knee in extension for 24 hours
4. Second arthroscopic I&D is recommended
   * Repeat synovial fluid aspiration and synovium cultures
5. 6 weeks of IV antibiotics tailored to culture and sensitivity
6. When the graft and associated hardware must be removed, a minimum 6-month waiting period after infection eradication is generally recommended before proceeding with graft reimplantation
   * Inection eradication indicated by normalized inflammatory markers and/or normal joint aspirate cell count and culture

Question 161

What structures comprise the anterolateral complex (ALC) of the knee (from superficial to deep)? [Knee Surgery, Sports Traumatology, Arthroscopy (2019) 27:166-176][Am J Sports Med. 2017 Sep; 45(11):2595-2603]

Answer 161

1. Superficial iliotibial band and iliopatellar band
2. Deep iliotibial comprised of:
   a. Proximal Kaplan fibers - traverse from the undersurface of the ITB in an anterior and proximal orientation to its femoral insertion distal to the lateral intermuscular septum
   b. Distal Kaplan fibers - originate adjacent to the proximal bundle and insert distal to it along the supracondylar ridge of the distal femur
   c. Capsule-osseous layer - originates in close proximity to the lateral gastrocnemius tubercle and inserts near a tubercle, called the lateral tibial tubercle, on the anterolateral aspect of the proximal tibia, between the Gerdy tubercle and the fibular head
3. Anterolateral ligament (ALL) and capsule

Question 162

What is the anatomy of the native Anterolateral Ligament (ALL) of the knee ?

[Arthroscopy 2019 35(2):670-681]

Answer 162

1. Femoral footprint

• Proximal and posterior to the lateral epicondyle
• Most variable in the literature but recent trend is proximal and posterior to lateral epicondyle

2. Tibial footprint

• Midpoint between the fibular head and Gerdy’s tubercle
• 4-7mm distal to tibial plateau

3. Lateral meniscus attachment
   * Between the body and anterior horn of the meniscus
4. Orientation
   * Fibres run anteroinferior
5. Length = 30.41 - 59mm
6. Thickness = 1 - 2mm

Question 163

What structures resist anterolateral rotation (internal tibial rotation) of the knee?

[Clin Sports Med 36 (2017) 135–153]

Answer 163

1. ACL
2. ALL
3. Posterior horn of the lateral meniscus
4. ITB

Question 164

What is the function of a lateral extra-articular tenodesis (LET) combined with an ACL reconstruction?

[Clin Sports Med 36 (2017) 135–153]

Answer 164

1. Protects the ACL graft
   * Demonstrates load-sharing during anterior translation and internal rotation of the tibia
2. Reduces tibial internal rotation

Question 165

What is a contraindication to LET (in addition to ACL recon)?

[Clin Sports Med 36 (2017) 135–153]

Answer 165

Posterolateral corner injury

• In such cases a tenodesis may tether the tibia in a posterolateral subluxed position

Question 166

What are the relative indications for a LET (in adition to ACL reconstruction)?

[Clin Sports Med 36 (2017) 135–153]

Answer 166

1. Revision ACL reconstruction
2. Grade 2 or 3 pivot shift (high-grade rotational laxity)
3. Young age of <25 years
4. Generalized ligamentous laxity
5. Genu recurvatum >10^o
6. Returning to pivoting sport (ie, soccer, basketball)

Question 167

Describe the LET procedure – Fowler Kennedy technique

[Clin Sports Med 36 (2017) 135–153]

Answer 167

1. A 5-cm curvilinear incision is placed just posterior to the lateral femoral epicondyle
2. An 8-cm-long x 1-cm-wide strip of ITB is harvested from the posterior half of the ITB
3. It is left attached distally at the Gerdy tubercle, freed of any deep attachments to vastus lateralis, released proximally, and a #1 Vicryl whip stitch is placed in the free end of the graft
4. The LCL is identified and small capsular incisions are made anterior and posterior to the proximal portion and Metzenbaum scissors are placed deep to the FCL to bluntly dissect out a tract for graft passage
5. The ITB graft is then passed beneath the LCL from distal to proximal
6. The lateral femoral supracondylar area is then cleared of soft tissue posterior and proximal to the lateral epicondyle
7. The graft is then held taught but not overtensioned, with the knee at 60 degrees flexion and the foot in neutral rotation to avoid lateral compartment overconstraint
8. The graft is secured using a small Richards staple and then folded back distally and sutured to itself using the #1 Vicryl whip stitch.
9. The posterior aspect of the ITB, where the graft was harvested, to avoid overtightening the lateral patellofemoral joint

Question 168

What are causes of overconstraint in the LET procedure? [Knee Surgery, Sports Traumatology, Arthroscopy

Answer 168

1. Fixation of the graft with the tibia in external rotation
2. Over-tensioning the graft

Question 169

What are the results of the STABILITY study comparing ACL reconstruction alone to ACL reconstruction and
LET in young patients (14-25 years) at high risk of graft failure? [Am J Sports Med. 2020 Feb; 48(2):285-2971

Answer 169

The addition of LET to a single-bundle hamstring tendon autograft ACLR in young patients at high risk of failure results in a statistically significant, clinically relevant reduction in graft rupture and persistent rotatory laxity at 2 years after surgery

Question 170

What is the function of the PCL (knee)?

[Arch Bone Jt Surg. 2018; 6(1): 8-18.]

Answer 170

Primary restraint to posterior tibial translation at all flexion angles

Question 171

What are the bundles of the PCL?

[JAAOS 2016;24:277-289]

Answer 171

1. Posteromedial
2. Anterolateral – larger and stronger

Question 172

What structures are part of the PCL complex and may act as secondary restraints to posterior tibial translation?

[JAAOS 2016;24:277-289]

Answer 172

1. Anterior meniscofemoral ligament (of Humphry)
   * From the posterior horn of the lateral meniscus and inserts on the femur anterior to the PM bundle
2. Posterior meniscofemoral ligament (of Wrisberg)
   * From the posterior horn of the lateral meniscus and inserts on the femur posterior to the PM bundle

Question 173

What is the mechanism of PCL injuries?

[JAAOS 2016;24:277-289]

Answer 173

Posteriorly directed force on the proximal tibia with the knee flexed

• “When the foot is dorsiflexed, force is transmitted through the patella and extensor mechanism. When the foot is plantarflexed, a posteriorly directed force is imparted to the proximal tibia.”

Question 174

Where is the most common location anatomically for the PCL to be injured in isolated PCL tears? [Skeleral Radiol. 2016 45(12): 1695-1703]

Answer 174

Midsubstance (69%) > proximal insertion (27%)

Question 175

What is the normal anterior tibial step-off and what is its significance?

[JAAOS 2016;24:277-289]

Answer 175

1. The medial tibial plateau normally lies approximately 1cm anterior to the medial femoral condyle
2. This position must be restored when performing a Lachman’s test to prevent false positive and when performing a posterior drawer to prevent a false negative

Question 176

What special tests should be performed when evaluating for PCL injuries?

[JAAOS 2016;24:277-289]

Answer 176

1. Posterior drawer (most sensitive and specific)
   * Graded based on posterior translation of the tibial plateau relative to its position on the contralateral side or relative to the medial femoral condyle (MFC)

• Grade I
  
  • 0-5mm posterior translation OR anterior relative to MFC
• Grade II
  
  • 6-10mm posterior translation OR even relative to MFC
• Grade III
  
  • >10mm posterior translation OR posterior relative to MFC

2. Quadriceps active test

• Patient lies supine with the hip flexed to 45° and the knee flexed to 90° and is instructed to slide his or her foot down the table
• Positive = tibia shifts anterior

3. Posterior sag

• Examiner holds the patient’s lower extremity with the hip and knee each flexed to 90°
• Positive = posterior sagging of the tibia or loss of prominence of the tibial tubercle.

4. Dynamic posterior shift test

• Leg is extended from start position of hip and knee flexed to 90°
• Positive = palpable clunk from reduction of the tibiofemoral joint

Question 177

What associated injury needs to be ruled out in the evaluation of PCL injuries?

[JAAOS 2016;24:277-289]

Answer 177

Posterolateral corner injury

• Dial test
  
  • With the patient prone an external rotation force is applied to the feet with the knees at 30° and 90°
  • Positive = >10° difference side to side
    • Only at 30° = PLC
    • Both at 30° and 90° = PLC and PCL

Grade 3 posterior drawer (>10mm) translation is associated with a PLC injury

Question 178

What additional radiographs can be obtained to evaluate for PCL injuries?

[JAAOS 2016;24:277-289]

Answer 178

Kneeling stress views

• Measurement between a line parallel to the posterior cortex of the tibia and the posterior aspect of Blumensaat’s line is compared between knees
• 0–7 mm of side-to-side difference in posterior displacement constitutes a partial PCL tear
• 8–11 mm constitutes an isolated complete PCL tear
• ≥12 mm of posterior translation constitutes a combined PCL and PLC or PMC knee injury

Question 179

What is the pattern of degenerative changes after a PCL injury?

[JAAOS 2016;24:277-289]

Answer 179

Patellofemoral and medial compartment OA

• Medial compartment experiences more anterior and medial contact pressures

Question 180

What is the management of PCL injuries?

[JAAOS 2016;24:277-289]

Answer 180

1. Nonoperative

• Isolated grade I and II
• Grade III with mild symptoms or low activity demands

2. Operative
   * Acute or chronic grade III who fail nonoperative management

Question 181

What are the two main operative techniques for treating ACL injuries?

[JAAOS 2016;24:277-289] [Arch Bone Jt Surg. 2018; 6(1): 8-18.]

Answer 181

1. Transtibial tunnel
2. Tibial inlay
   * Involves creating a trough at the tibial attachment of PCL to match with the graft bone plug fixed with a cannulated screw
   * Traditional inlay technique requires an open posteromedial approach (Burks) between the semimembranosus tendon and the medial head of the gastrocnemius muscle
   * Potential benefits
   
   • Bony healing
   • Avoidance of graft abrasion at the so-called killer tibial turn
   • Large graft sizes

Question 182

Describe the Tibial inlay technique for PCL reconstruction?

[Curr Rev Musculoskelet Med. 2018 Jun; 11(2): 316–319]

Answer 182

1. Patient is prepped and draped in the lateral decubitus position with affected leg up
2. Outside-in femoral tunnel

• Patient is positioned supine
• Diagnostic arthroscopy performed and remnant PCL debrided and footprint identified
• Medial skin incision is made medial to the patella and through the capsule to identify the guide placement
• An outside-in arthroscopic guide is used to place the guide pin which is over-reamed (usually 10mm)
• An 18-gauge metal wire loop is then placed through the femoral tunnel into the posterior aspect of the femoral notch for later graft passage
  3. PCL graft preparation
• Achilles tendon allograft
  
  • Bone plug is shaped and predrilled and tapped for a 6.5mm cancellous screw
  • Tendinous portion is tubularized and sized (10mm)

4. Open tibial inlay

• Patient is positioned prone
• Burks posteromedial approach is made between the medial head of gastrocs and semimembranosus
  • Vertical capsulotomy is made and the native PCL insertion is resected with osteotomes and shaped to accept the graft
• The graft is fixed bone-to-bone with the 6.5mm screw
• The tendinous portion is shuttled to the femoral tunnel with the 18-gauge wire
• Wound is closed
  5. Graft tensioning
• Patient is positioned supine
• Graft is tensioned with the knee at 90 and interference screw is used for fixation

Question 183

What is the anatomy of the superficial MCL of the knee?

[J Bone Joint Surg Am. 2010;92:1266-80]

Answer 183

One femoral and two tibial attachments

• Femoral attachment = 3.2mm proximal and 4.8mm posterior to the medial epicondyle
• Proximal tibial attachment = 12.2mm distal to the tibial joint line
  • Primarily to soft tissue over the termination of the anterior arm of the semimembranosus tendon
• Distal tibial attachment = 61.2mm distal to the tibial joint line

Question 184

What is the function of the superficial MCL?

[Instr Course Lect 2015;64:531–542]

Answer 184

1. Primary restraint against valgus stress at 30^o flexion
   * Secondary restraint to external rotation of the tibia
2. Secondary restraing to tibial internal rotation (along with the posterior oblique ligament) at all flexion angles

Question 185

What is the anatomy of the deep MCL?

[J Bone Joint Surg Am. 2010;92:1266-80]

Answer 185

Thickening of the capsule with attachments to the medial meniscus

• Divided into meniscotibial and meniscofemoral components
• Meniscofemoral attachment = 12.6 mm distal and deep to the femoral attachment of the superficial MCL
• Meniscotibial attachment = 3.2 mm distal to the medial joint line
  
  • Just distal to the tibial articular cartilage

Question 186

What is the anatomy of the posterior oblique ligament (POL)?

[J Bone Joint Surg Am. 2010;92:1266-80]

Answer 186

1. Tibial origin
   * A reflection from the distal semimembranosus tendon insertion on the posteromedial tibia
2. Femoral origin
   * Central arm of the posterior oblique ligament attaches on the femur 7.7 mm distal and 2.9 mm anterior to the gastrocnemius tubercle

Question 187

How are injuries to the medial knee ligaments classified?

[J Bone Joint Surg Am. 2010;92:1266-80]

Answer 187

1. American Medical Association Standard Nomenclature of Athletic Injuries
   * Severity system
   
   • Grade I = Localized tenderness and no laxity
   • Grade II = Localized tenderness and partially torn medial collateral and posterior oblique fibers
     
     • Fibers are still opposed, and there may or may not be pathologic laxity
   • Grade III = Complete disruption and laxity with an applied valgus stress.
     * Laxity system (subjective gapping of the medial joint line)
   • Grade 1+ = 3 to 5 mm
   • Grade 2+ = 6 to 10 mm
   • Grade 3+ >10 mm
2. Fetto and Marshall Classification [Iowa Orthop J. 2006; 26: 77–90.]

• Grade I = no valgus laxity at both 0 and 30 degrees of flexion
• Grade II = valgus laxity at 30 degrees of flexion but stable at 0 degrees of flexion
• Grade III = valgus laxity at both 0 and 30 degrees of flexion

Question 188

What structures are thought to be intact and disrupted in the Fetto and Marshall Classification?

[J Bone Joint Surg Am. 2010;92:1266-80][Journal of Orthopaedics 14 (2017) 550–554]

Answer 188

Grade I

• No valgus laxity at both 0 and 30^o of flexion
• Both superficial MCL and POL intact

Grade II

• Valgus laxity at 30^o of flexion but stable at 0^o of flexion
• Superficial MCL disrupted and POL intact

Grade III

• Valgus laxity at both 0 and 30^o of flexion
• Both superficial MCL and POL disrupted
• Often associated with an ACL injury

Question 189

Where anatomically is the superficial MCL typically injured?

[Sports Med Arthrosc Rev 2015;23:e1–e6)]

Answer 189

Femoral insertion > tibial insertion > midsubstance

Question 190

What are the radiographic features of a MCL injury?

Answer 190

1. Stress radiographs [Am J Sports Med. 2010;38:330-8]

• Isolated superficial MCL
  
  • Medial joint gapping of 1.7mm at 0° and 3.2mm at 20° of flexion
• Superficial MCL, deep MCL and POL
  • Medial joint gapping 6.5mm at 0° and 9.8 mm at 20° of flexion
    
    2. Pellegrini-Stieda syndrome
• Intraligamentous calcification in the region of the femoral attachment of the MCL caused by the chronic tear of the ligament

Question 191

What are the indications for an MRI with a clinically suspected MCL injury?

[Sports Med Arthrosc Rev 2015;23:e1–e6)]

Answer 191

1. Grade 1 or 2 injuries with concern for associated injuries

• Relative indications:
  
  • Effusion
  • Suspected cruciate injury
  • Patellar instability
  • Lateral joint line pain

2. Grade 3 injuries

• Assess for concomitant injuries
  
  • Eg. cruciate injury, stener-like lesion of the knee, etc

Question 192

What are the MRI features of a MCL injury?

[Sports Med Arthrosc Rev 2015;23:e1–e6)]

Answer 192

Grade I

• Ligament swelling and edema
• Partial tearing with all structures overall intact

Grade II

• Tearing of some medial structures with others intact
  
  • Eg. superficial MCL is torn with deep MCL intact, or vice versa

Grade III

• Complete disruption of the superficial and deep layers
• Often with significant soft tissue fluid and edema from intra-articular fluid leak

Bone bruises [J Bone Joint Surg Am. 2010;92:1266-80]

• Lateral tibial plateau and lateral femoral condyle

***Best assessed on the coronal images

Question 193

What is a stener-like lesion of the knee?

[AJR Am J Roentgenol. 2019 Aug 28:1-5.][Clin Orthop Relat Res (2010) 468:289–293]

Answer 193

Defined as a distal tear of the superficial MCL with proximal retraction and interposition of osseous or soft-tissue structures between the ligament and its tibial attachment

• Prevents anatomic healing and with potential for secondary dynamic valgus instability
• Most commonly stener-like lesions represent interposition of the pes anserinus (83%)
  
  • May also involve entrapment of the distal tibial portion of the superficial MCL in the tibiofemoral joint or in a reverse Segond fracture (17%)

Question 194

What is the significance of stener-like lesion of the knee?

[AJR Am J Roentgenol. 2019 Aug 28:1-5.]

Answer 194

1. High association with multi-ligament knee injuries
   * Most common associated ligament injury being ACL
2. Prevents anatomic reduction and healing resulting in valgus instability

Question 195

What is the management of a stener-like lesion of the knee?

[AJR Am J Roentgenol. 2019 Aug 28:1-5.]

Answer 195

Acute open reduction and repair

Question 196

What are the indications for nonoperative management of acute medial sided knee injuries?

[Sports Med Arthrosc Rev 2015;23:71–76]

Answer 196

Isolated Grade I, II and III MCL injuries

Question 197

What are the indications for operative management of acute medial sided knee injuries?

[Sports Med Arthrosc Rev 2015;23:71–76] [Iowa Orthop J. 2006; 26: 77–90.]

Answer 197

1. Acute repair

• Large bony avulsion
• Stener-like lesion of the knee
  • Pes anserine entrapment
  • Intra-articular entrapment
• MRI finding of complete tibial sided avulsion in athletes
• Presence of AMRI
• Presence of valgus instability in 0 degrees of flexion in an underlying valgus knee alignment
• Associated tibial plateau fracture
  2. Delayed repair
• Combined ACL or other ligament reconstruction if the EUA shows valgus laxity in 0 degrees of flexion
  3. Augmentation
• Combined with any repair if local tissue is deficient
  4. Reconstruction
• Symptomatic chronic valgus laxity/medial instability
  5. Distal femoral varus osteotomy
• Chronic valgus laxity and valgus bony alignment

Question 198

What are options for acute repair of the superficial MCL and POL?

[Instr Course Lect 2015;64:531–542][Sports Med Arthrosc Rev 2015;23:71–76]

Answer 198

1. Sutures alone
2. Suture plus suture anchor
3. Staple
4. Screw and washer

Question 199

What technique can be used to augment the superficial MCL repair?

[Instr Course Lect 2015;64:531–542]

Answer 199

Semitendinosus autograft

• Released proximally at the musculotendinous junction leaving the distal insertion intact
• Distal tibial fixation 6 cm from the proximal joint line with two double-loaded suture anchors
• Graft is then passed deep to the sartorius fascia
• Femoral fixation in a closed socket tunnel 3.2 mm proximal and 4.8 mm posterior to the medial epicondyle and fixed with an interference screw
• Proximal tibial attachment is then secured 12 mm distal from the proximal joint line using a double loaded suture anchor

Question 200

What are the key features of a LaPrade superficial MCL and POL reconstruction?

[J Bone Joint Surg Am. 2010;92:1266-80] [Instr Course Lect 2015;64:531–542]

Answer 200

1. Single anteromedial incision
2. Two separate grafts
3. 4 reconstruction tunnels at anatomic femoral and tibial insertions of the superficial MCL and POL
4. Proximal tibial insertion of the superficial MCL is recreated with suture anchors
5. Superficial MCL is tensioned at 30^o flexion
6. POL is tensioned at 0^o flexion

Question 201

What is the anatomy of the lateral collateral ligament of the knee?

[Instr Course Lect 2015;64:531–542]

Answer 201

1. Femoral origin
   * 1.4 mm proximal and 3.1 mm posterior to the lateral epicondyle
2. Fibula origin
   * 28.4 mm distal to the tip of the fibular styloid

Question 202

What is the function of the LCL (knee)?

[Instr Course Lect 2015;64:531–542]

Answer 202

1. Primary varus stabilizer at 0° and 30° of flexion
2. Secondary restraint against tibial internal and external rotation

Question 203

What percentage of sporting-related LCL injuries are isolated (no associated pathology)?

[JAAOS 2018 26(6):e120-e127]

Answer 203

<2%

Question 204

What physical examination special test is most relevant for assessing the LCL?

[JAAOS 2017;25:280-287]

Answer 204

Varus stress test

• Isolated LCL injury
  
  • Laxity at 30° and stable at 0° of flexion
• LCL injury combined with PLC +/- cruciates
  
  • Laxity at both 30° and 0° of flexion

Question 205

What radiographic findings may be associated with LCL injuries?

[Sports Med Arthrosc Rev 2015;23:10–16] [Instr Course Lect 2015;64:531–542]

Answer 205

1. Arcuate fracture
   * Avulsion of the fibular head or portion of
2. Varus stress radiograph
   * Isolated LCL injury = 2.7mm lateral gapping
   * LCL and grade III PLC injury = 4.0mm lateral gapping

Question 206

What is the MRI grading system for LCL injuries?

[JAAOS 2018 26(6):e120-e127]

Answer 206

Grade I

• Subcutaneous fluid surrounding the midsubstance of the ligament at one or both insertions

Grade II

• Partial tearing of ligament fibers at either the midsubstance or one of the insertions, with increased edema in the area

Grade III

• Complete tearing of ligament fibers at either the midsubstance or one of the insertions
• Associated with increased edema

Question 207

What are the indications for nonoperative management of LCL injuries?

[JAAOS 2018;26:e120-e127]

Answer 207

Grade I and II injury

Question 208

What are the indications for repair of a LCL injury?

[Instr Course Lect 2015;64:531–542]

Answer 208

Acute avulsion injury (within 3 weeks)

Question 209

What are the indications for reconstruction of LCL injury?

[Instr Course Lect 2015;64:531–542]

Answer 209

1. Acute Grade III midsubstance tears or attenuation
2. Chronic LCL injury with symptomatic instability

Question 210

What are the indications for valgus producing HTO in context of LCL tear?

[Instr Course Lect 2015;64:531–542]

Answer 210

Chronic symptomatic LCL injury with varus deformity

• HTO should precede reconstruction
  
  • May eliminate need for reconstruction in some cases

Question 211

What are the 3 key anatomical structures that make up the posterolateral corner (PLC) of the knee?

[Rev Bras Ortop. 2015 50(4): 363–370]

Answer 211

1. Lateral collateral ligament
2. Popliteus tendon
3. Popliteofibular ligament

Question 212

Other than the primary components of the PLC, what other structures stabilize the posterolateral corner of the knee?

[JAAOS 2008;16:506-518] [Sports Med Arthrosc Rev 2015;23:2–9)]

Answer 212

1. Posterolateral capsule
2. Lateral meniscus
3. Iliotibial band
4. Fabellofibular ligament
5. Long and short heads of the biceps femoris
6. Lateral head of gastrocnemius muscle

Question 213

Describe the anatomy of the LCL, popliteus tendon and the popliteofibular ligament?

[Sports Med Arthrosc Rev 2015;23:2–9)]

Answer 213

1. Lateral collateral ligament

• Proximal attachment
  
  • Proximal and posterior to the lateral epicondyle of the femur
• Distal attachment
  • Lateral aspect of the fibular head
    
    • 8.2mm posterior to the anterior margin of the fibular head and 28.4mm distal to the fibular styloid tip
      2. Popliteus tendon
• Proximal attachment
  • Anterior and distal to the lateral epicondyle
    
    • At the anterior 1/5 of the popliteal sulcus, just posterior to the lateral femoral condyle articular cartilage
    • Attachment is 18.5mm oblique from the LCL femoral attachment
• Distal attachment
  • Proximal posteromedial aspect of the tibia
• ***Note: The tendon passes from intra-articular through the popliteal hiatus to become extra-articular
  
  • Gives off 3 popliteomeniscal fascicles to anchor to the lateral meniscus
    
    3. Popliteofibular ligament
• Proximal attachment
  
  • Musculotendinous junction of the popliteus
• Distal attachment
  
  • Posteromedial downslope of the fibular styloid process

Question 214

What is the consequence of a missed PLC injury?

[Rev Bras Ortop. 2015 50(4): 363–370]

Answer 214

1. Failure of cruciate reconstructions
2. Recurrent instability

Question 215

What are the special tests for the PLC?

[JAAOS 2017;25:280-287]

Answer 215

1. External rotation recurvatum test

• Lower leg is picked up by the great toe
• Relative hyperextension, tibial external rotation and knee varus compared to the contralateral side

2. Posterolateral rotary drawer test

• With the knee flexed to 90°, the hip flexed to 45°, and the foot fixed in slight external rotation (usually best at 15°), a posteriorly directed force is applied through the tibial tuberosity
  
  • The PCL is relaxed in this position, allowing rotary and translator laxity
• With an isolated PLC injury
  
  • More rotatory instability with slight ER than with neutral rotation because the PCL provides more translational stability with neutral rotation
• With an isolated PCL injury
  
  • More translatory instability than rotary instability will be present

3. Dial test

• Patient prone, external rotation applied to foot and thigh foot angle compared side to side at 30 and 90 of knee flexion (Positive = 10^o difference)
  
  • Increased at 30° = isolated PLC
  • Increased at 30° and 90° = PLC and PCL
    4. Standing apprehension test
• Patient stands with the knee slightly bent and internally rotates the torso away from the leg, producing an internal rotation of the femur on the tibia
• Positive = Apprehension or instability

Question 216

What classifications have been proposed to grade PLC injuries?

[JAAOS 2008;16:506-518]

Answer 216

1. Hughston classification

• Severity graded on varus laxity
• Grade I = 0 to 5mm
  • Sprains without tensile failure of any capsule-ligamentous structures
• Grade II = 6-10mm
  
  • Partial injuries with minimal abnormal laxity
• Grade III = >10mm
  
  • Complete disruptions with significant laxity
    
    2. Fanelli classification
• Severity graded on external rotation and varus laxity
• Type A
  
  • Isolated rotational injury to the PFL and popliteus tendon complex
• Type B
  • Rotational injury with a mild varus component
  • Represents an injury to the PFL and popliteus tendon complex, as well as attenuation of the LCL
• Type C
  
  • Posterolateral instability with significant rotational and varus component secondary to complete disruption of the PFL, popliteus tendon complex, LCL, lateral capsule, and cruciate ligament or ligaments
    
    3. Modified Hughston classification
• Severity graded on ER and varus laxity
• Grade I
  
  • Minimal instability
  • Either varus or rotational instability of 0 to 5mm or 0° to 5°
• Grade II
  • Moderate instability (6 to 10mm or 6° to 10°)
• Grade III
  
  • Significant instability (>10 mm or >10°)

Question 217

What are the indications for nonoperative management of PLC injuries?

[Rev Bras Ortop. 2015 50(4): 363–370]

Answer 217

Acute, isolated Grade I and II PLC injuries

Question 218

What are the indications for operative management of PLC injuries?

[Rev Bras Ortop. 2015 50(4): 363–370]

Answer 218

1. Isolated grade III PLC injuries
2. Combined PLC injuries
3. Chronic symptomatic PLC injury failing nonoperative management

Question 219

What are the indications for repair (vs. reconstruction) of PLC injuries?

[Rev Bras Ortop. 2015 50(4): 363–370]

Answer 219

Acute (<3 weeks) LCL and popliteus tendon avulsions, without midsubstance injury

Question 220

In general, in a PLC injury what type of reconstruction should be performed and of what structures?

[Knee Surgery, Sports Traumatology, Arthroscopy (2019) 27:2520–2529]

Answer 220

Anatomical reconstruction

• Reconstruction of primary PLC components
  
  • LCL, popliteus tendon and PFL
• Repair of secondary structures (hybrid construct)

***Note: Valgus producing HTO should precede or occur concurrently with reconstruction in varus knees

Question 221

What are 3 described PLC reconstructions and their distinguishing features?

Answer 221

1. Larson [Arthroscopy. 2002 Feb; 18(2 Suppl 1): 1-8]
   
   1. Main features
      
      1. Single femoral tunnel at the lateral epicondyle (isometric point) ii. Fibular tunnel directed from anterior to posterior ili. Graft limbs reconstruct the LCL and popliteofibular ligament
2. Arciero [Arthroscopy: 2005 Sep;21(9): 1147]
   
   1. Main features
      
      1. 2 femoral tunnels near the anatomic footprint of the LCL and popliteus
      2. Fibular tunnel oriented anterolateral to posteromedial starting just distal to the LCL fibular insertion
      3. 2 separate graft limbs reconstruct the LCL and popliteus tendon in a more anatomic orientation
3. Laprade /Arthrosc Tech. 2016 Jun; 5(3): e563-e572.]
   
   1. Main features
      
      1. 2 femoral tunnels at the anatomic footprint of the LCL and popliteus
      2. Tibial tunnel located from posterolateral proximal tibia (location of popliteus musculotendinous junction) to anterior tibia between tibial tubercle and Gerdy’s tubercle
      3. Fibular tunnel from LCL attachment to the posteromedial down slope of the fibular styloid
      4. Graft limbs reconstruct the LCL, popliteus and popliteofibular ligament

Question 222

what are the anatomical features of the native quadriceps tendon to consider when harvesting

Answer 222

• length = 7.5-8cm (myotendinous junction to superior pole of patella)
  
  • patient heightis the strongest predictor of length
• width = 2.5-3cm
  
  • widest point is 3cm proximal to the superior pole of the patella
• thickness = 18 +/- 3mm for males, 16 +/- 2mm for females

Question 223

2 forms of quadriceps autograft that can be harvested

Answer 223

• all soft tissue
• quadriceps tendon with proximal patellar bone block

Question 224

characteristics of the quadriceps tendon graft that are advantageous compared to BTB graft

Answer 224

• thicker
  
  • patellar tendon thickness is less than 6mm
• greater intra-articular volume
  
  • 87.5% greater compared to BTB
• more native quadriceps tendon remaining after harvest compared to patellar tendon

Question 225

advantages of the quadriceps autograft

Answer 225

1. predictability of graft size and volume
   
   1. compared to BTB autograft, there is a greater intra-articular volume and greater residual tendon remaining
2. no studies demonstrating tunnel-widening
3. decreased anterior knee pain and kneeling (compared to BTB)
4. less risk to the infrapatellar branch of the saphenous nerve (compared to BTB)
5. more flexion strength and hanstring/quad isokinetic ratio compared to hamstring
6. similar funcitonal outcomes compared to BTB and hanstring
   
   1. including stability, patient reported outcomes, ROM, strength and failure/rupture rates

Question 226

complications associated with quad tendon autograft

Answer 226

• hematoma formation (Due to hypervascular region)
• cosmetic defects
  
  • popeye like sign has been associated with too proximal harvest into rectus myofascia funciton
• patellar fractures
  
  • recommended that harvest is less than 30% thickness of patella

Question 227

overall failure rate of primary ACL reconstruction

Answer 227

1. <5%
   
   1. failure rate as high as 28% in young active males

Question 228

RF for ACL failure

Answer 228

1. technical errors
2. younger age
3. higher activity level
4. irradiated allograft
5. lower limb malalignment
6. increased posterior tibial slope

Question 229

most common cause of primary ACL reconstruction failure

Answer 229

technical error - improper tunnel placement outside the native femoral and tibial ACL footprints

Question 230

technical errors leading to ACL re-rupture

Answer 230

1. non anatomic tunnel placement
2. improper graft tensioning
3. inadequate graft fixation
4. insufficient graft material

Question 231

consequence of improper tunnel placement on the femoral and tibial side

Answer 231

1. Errors in femoral tunnel placement

a. Too anterior = excessive graft tensioning with flexion leading to loss of knee flexion or stretching of the graft
b. Too posterior = excessive graft tension in extension with laxity in flexion
c. To vertical = inadequate rotational stability

2. Errors in tibial tunnel placement

a. Too anterior = notch impingment and loss of extension
b. Too posterior = PCL impingement and loss of flexion
c. Too medial/lateral = notch impingement and iatrogenic tibial plateau cartilage damage

Question 232

indications for 2-stage ACL revision reconstruction

Answer 232

tunnel widening >15mm or >100% original diameter
substantial tunnel overlap
infection
arthrofibrosis

Question 233

indications for single-stage acl revision reconstruction

Answer 233

1. appropriately placed tunnels
2. good bone stock
3. hardware that can be removed or will not obstruct revision
4. inappropriately placed tunnels that do not interfere with anatomically placed tunnels
   - if previous femoral tunnes violate blumensaat’s line then an anatomically placed tunnel can be placed while avoiding the previous tunnel

Question 234

recommended interval of time between 1st and 2nd stage revision ACL when bone grafting is utilized

Answer 234

12-24 wks

Question 235

concomitant pathology that can be addressed to minimize risk of ACL revision failure

Answer 235

• increased posterior tibial slope
  
  • procedure tibial deflexion osteotomy (anterior closing wedge)
    
    • failed revision ACL reconstruction with posterior tibial slop >12°
• varus malalignment
  
  • procedure - high tibial osteotomy
    
    • indications
      
      • medial compartment arthritis
      • varus thrust
      • instability in double and triple varus
• anterolateral rotatory instability
  
  • procedure - anterolateral ligament reconstruction or lateral extra-articular tenodesis
    
    • indications
      
      • grade 3 pivot shifts
      • ACL reconstruction failure with no other identifiable cause
• meniscal deficiency
  
  • procedure = meniscal repair
    
    • indications
      
      • RAMP lesions
      • repairable meniscal lesions
  • procedure = meniscal allograft transplantation
    
    • indications = irreparable meniscal tears or previous total or near-total meniscectomies

Question 236

What are the anterior, middle and posterior thirds of the medial side of the knee as described by Robinson?

[JAAOS 2017;25:752-761]

Answer 236

Anterior 1/3

• Medial border of the patellar tendon to the anterior border of the superficial MCL

Middle 1/3

• Width of the superficial MCL

Posterior 1/3

• Posterior border of the superficial MCL to the medial border of the medial head of gastrocnemius
• Posterior 1/3 = posteromedial corner

Question 237

What are the 5 components of the PMC?

[JAAOS 2017;25:752-761]

Answer 237

1. Posterior oblique ligament
2. Semimembranosus tendon and its expansions
3. Oblique popliteal ligament
4. Posteromedial joint capsule
5. Posterior horn of the medial meniscus

Question 238

Describe the anatomy of the posterior oblique ligament (POL)?

[JAAOS 2017;25:752-761]

Answer 238

1. Proximal attachment
   * Distal and posterior to the adductor tubercle
2. Runs distally and posterior at 25° to the superficial MCL fibres
3. Distally has 3 arms

• Superficial
• Central (tibial)
  
  • Largest and thickest
  • Reinforces the posteromedial capsule
  • Attaches to the posteromedial aspect of the medial meniscus and adjacent tibia
  • Main structure requiring repair or reconstruction
• Capsular

Question 239

What are the 5 major arms or expansions of the semimembranosus tendon?

[JAAOS 2017;25:752-761]

Answer 239

1. Pars reflecta (anterior arm)
   * Inserts into medial tibia
2. Direct posteromedial tibial insertion (primary attachment)
   * Inserts into posteromedial tibia (tuberculum tendinis)
3. OPL insertion
4. POL insertion
5. Popliteus aponeurosis expansion

Question 240

Describe the anatomy of the oblique popliteal ligament?

[JAAOS 2017;25:752-761]

Answer 240

Extends from the main semimembranosus tendon passing laterally and proximal to attach to the posterior capsule (meniscofemoral portion), fabella, and plantaris muscle

• Difficult to distinguish from the posterior capsule

Question 241

What attachments are present on the posterior horn of the medial meniscus?

[JAAOS 2017;25:752-761]

Answer 241

1. Posteromedial capsule (deep MCL)
2. POL
3. Semimembranosus expansion

Question 242

What is the most frequently injured structure in PMC injuries?

[JAAOS 2017;25:752-761]

Answer 242

POL

Question 243

What are the 3 major patterns of PMC injury?

[JAAOS 2017;25:752-761]

Answer 243

1. POL + semimembranosus tendon [capsular arm] (70%)
2. POL + complete peripheral meniscus detachment (30%)
3. POL + semimembranosus tendon + peripheral meniscus detachment (19%)

NOTE: isolated PMC injury is rare

Question 244

What are the findings on physical examination associated with PMC injury?

[JAAOS 2017;25:752-761]

Answer 244

1. AMRI (anteromedial rotatory instability)

• Hallmark of PMC injury
• Characterized by anterior subluxation of the anteromedial tibia on the femoral condyle
• Valgus stress at 30° flexion with foot externally rotated
  
  • Positive = medial joint gapping and anterior subluxation of the medial tibial plateau relative to the femur
    
    • Correlates with combined MCL and PMC
      2. Anterior drawer with foot 15° externally rotated
• Positive = anteromedial tibial plateau subluxation
  
  • Indicates PMC injury
    
    3. Valgus stress at 0°
• Positive = gapping of medial joint line
  
  • Suggests MCL, cruciate and PMC injury

4. Posterior drawer with tibia in neutral and internal rotation

• Positive = equal posterior translation
  
  • PCL and PMC injury
• Decreased posterior translation with internal rotation suggests isolated PCL injury

Question 245

What are the indications for surgical repair or reconstruction of the PMC?

[JAAOS 2017;25:752-761]

Answer 245

1. Multiligamentous injuries with AMRI
2. Medial gapping or instability with valgus stress at full extension
3. Positive posterior drawer with internal rotation

Question 246

When can PMC repair be considered?

[JAAOS 2017;25:752-761]

Answer 246

Acute injury

• Particularly with distal tibial sided MCL and PMC tears

Question 247

When should PMC reconstruction be considered?

[JAAOS 2017;25:752-761]

Answer 247

1. PMC tissue is not favourable (attenuated, midsubstance)
2. Chronic, symptomatic PMC injuries

Question 248

What is the anatomic reconstruction of the PMC?

[JAAOS 2017;25:752-761]

Answer 248

2 grafts to reconstruct

• Superficial MCL
  
  • Distal tunnel 6cm below joint line
  • Proximal tunnel just proximal and anterior to the medial epicondyle
  • Tensioned in 20° flexion and neutral rotation
  • Proximal tibial attachment is made with a suture anchor 12-13mm distal to joint line
• POL
  • Distal tunnel just anterior to the direct arm attachment of the semimembranosus
  • Proximal tunnel 8mm distal and 3mm anterior to the gastrocnemius tubercle
  • Tensioned and fixed in full extension and neutral rotation

Question 249

What are the consequences of an unrecognized PMC injury?

[JAAOS 2017;25:752-761]

Answer 249

1. Chronic valgus laxity
2. Late graft failure after ACL reconstruction

Question 250

Where is the qudriceps tendon most commonly ruptured anatomically? [JBJS REVIEWS 2018;610):el]

Answer 250

Quadriceps tendon can be divided into 3 zones relative to the superior pole of the patella
a. Zone 1 (0 to 1cm)
b. Zone 2 (>1 to 2cm) - most common (relatively avascular)
c. Zone 3 (>2cm)

Question 251

What are the risk factors for quadriceps tendon tear? [JBJS REVIEWS 2018;6(10):el]

Answer 251

1. Long standing tendinopathy
2. Diabetes
3. Thyroid disorders
4. Renal disease
5. Hyperlipidemia
6. Systemic inflammatory disease
7. Medications (statins, fluoroquinolones)
8. Age (>40)
9. Men

Question 252

When should quadriceps tendon repair be performed?

Answer 252

Within 2 weeks of injury

Question 253

What is considered the gold standard treatment of quadriceps tendon tears? [JBJS REVIEWS 2018;6(10):el]

Answer 253

Heavy non-absorbable suture in locking fashion grasping the quadriceps tendon, sutures are passed through drill holes in the patella and tied over bone bridge (transosseous tunnel fixation)

Question 254

What are reported advantages of suture anchor type constructs in the fixation of quadriceps tendon tears? [JB.JS Apr;23(4): 1039-45]
REVIEWS 20186(1) el][Anthroscopy. 2016 Jun;32(6):1117-24][Knee Surg Sports Traumatol Arthrosc. 2015

Answer 254

Smaller incision, less dissection, reduced operative time, decreased gap formation, increased load to failure

Question 255

What is the blood supply to the menisci?

[Am J Sports Med 1982; 10(2):90]

Answer 255

1. Primary = medial and lateral geniculate arteries (both superior and inferior)
   * Gives rise to a perimeniscal capillary plexus in the synovial and capsular tissue supplying the peripheral meniscus (10-30%)
2. Secondary - middle geniculate artery

• Within the synovial sheath of the cruciate ligaments
• Supplies the anterior and posterior horns for short distance

3. Relative avascular area of the lateral meniscus at the posterolateral aspect adjacent to the popliteus tendon
4. Three vascular zones [AAOS comprehensive review 2, 2014]

• Red-red – peripheral 1/3 (vascular)
• Red-white – middle 1/3 (avascular)
• White-white – central 1/3 (avascular)

Question 256

what are clinical differences between transosseous suture and suture anchor quadriceps tendon repair? PLoS one 2018 Mar 19;13(3)

Answer 256

no differences in patient reported outcomes, strength, ROM or re-tear rate

Question 257

What is the innervation of the menisci?

[Clinical Anatomy 28:269–287 (2015)]

Answer 257

1. Recurrent peroneal branch of the common peroneal nerve
2. Mechanoreceptors and free nerve endings located in the anterior and posterior horns and peripheral 1/3-2/3

Question 258

What are the stabilizing ligaments of the medial and lateral meniscus? [Sports Med Arthrosc Rev 2017;25:219-226]

Answer 258

• Transverse/intermeniscal ligament
• Coronary ligament
• Anterior meniscofemoral ligament (of Humphrey)
• Posterior meniscofemoral ligament (of Wrisberg)
• Deep MCL (meniscotibial and meniscofemoral ligaments)
• (meniscal root attachment)

Question 259

What is a meniscal flounce and what is its significance? [Sports Med Arthrosc Rev 2017;25:219-226]

Answer 259

1. Meniscal flounce = a buckle in the meniscus due to knee position
2. Significance = normal finding, the absence of a flounce should prompt the surgeon to probe the meniscus for an occult tear

Question 260

What are 4 MRI features that would suggest a bucket-handle tear? [Knee Surg Sports Traumatol Arthrosc (2006) 14: 343-349]

Answer 260

1. Double-PCL sign (sagittal)
2. Fragment in the intercondylar notch (coronal)
3. Double anterior horn sign/Double delta sign (sagittal)
4. Absent bow-tie sign (sagittal)

Question 261

What is a recommended algorithm for the evaluation and management of meniscal tears? [Bone Joint J 2019;101-B: 652-659]

Answer 261

• Based on history, physical and imaging there are five main meniscal tear scenarios:
  
  • Locked knee
    
    • Treatment = urgent arthroscopic surgery
  • Acute injury + repairable meniscus tear
    
    • Treatment = consider arthroscopic surgery if patient is a suitable candidate
      
      • No recommended timeline for repair - shared decision between surgeon and patient
  • Non-Acute injury + meniscus tear is treatable
    
    • Treatment = at least 3 months of non-operative treatment
  • Consider non-urgent arthroscopic surgery if symptoms persist >3 months
  • Non-Acute injury + meniscus tear is possibly treatable
    
    • Treatment = at least 6 months of nonoperative treatment
      
      • Consider non-urgent arthroscopic surgery in selected cases if symptoms persist >6 months
  • Advanced arthritis + meniscus tear
    
    • Treatment = nonoperative
      
      • Arthroscopic surgery is not appropriate

Question 262

What is the function of the meniscus?

[Clinical Anatomy 28:269–287 (2015)]

Answer 262

1. Load transmission
   * Converts compressive forces into concentric forces
   
   • Hoop stresses transmitted to bony anchors of meniscal horns by circumferential fibres of meniscus
   • Diminishes forces on articular cartilage
     * ​40-60% of the load in extension and up to 90% in flexion
2. Shock absorption
3. Stability (limits motion in all directions)
4. Proprioception
5. Joint lubrication and nutrition (?theoretical)

Question 263

What are the indications for meniscal repair?

[J Am Acad Orthop Surg 2013;21:204-213]

Answer 263

1. Tear > 1cm but <4cm in length
2. Red-red zone tears (that tears within 2 mm of the meniscal vascular rim)
3. Vertical/longitudinal tears
4. Age <40 years
5. Acute tears (<6 weeks)
6. Concurrent ACL reconstruction
7. No mechanical malalignment
8. Radial tears that extend entire width of meniscus
9. Meniscal root tears

Question 264

What are the 3 main options for meniscal repair?

[J Am Acad Orthop Surg 2013;21:204-213]

Answer 264

1. Inside-out (gold standard)
2. Outside-in
3. All inside

Question 265

For the inside out technique of meniscal repair describe the medial and lateral approach?

[Arthrosc Tech. 2017 Aug; 6(4): e1221–e1227.]

Answer 265

1. Medial approach

• 4cm vertical incision posterior to MCL
  
  • 1/3 above joint and 2/3 below joint
• Sartorial fascia is opened inline
• Pes anserinus tendons are taken distal
• Interval between the medial head of gastrocs and capsule is developed staying proximal to semimembranosus tendon
  
  • Spoon is inserted in this interval
    
    2. Lateral approach
• 4cm oblique incision starting at Gerdy’s extending proximal and anterior
• ITB is split in line with its fibres
• Staying posterior to LCL and anterior to the biceps femoris the interval between the lateral head of gastrocs and the capsule is developed
  
  • Spoon is inserted in to this interval

Question 266

What is the function of the meniscus root?

[JBJS REVIEWS 2016;4(8):e2] [AJSM 2014; 42(12): 3016]

Answer 266

Dissipate axial loads by conversion to hoop stresses

• Axial load causes circumferential fibres to stretch and meniscus to extrude
• Tensile ‘hoop stress’ resists this extrusion in the presence of intact meniscal roots
• Distribution of hoop stresses by the circumferential fibers helps to transmit relatively even axial loads across the joint surfaces

Question 267

What is the consequence of meniscal root tears?

[JBJS REVIEWS 2016;4(8):e2]

Answer 267

1. Meniscal extrusion
2. Loss of hoop stress
3. Increased tibiofemoral contact pressures
   * Equivalent to total meniscectomy
4. Accelerated degenerative changes

Question 268

What are the typical clinical symptoms following a meniscal root tear?

[JBJS REVIEWS 2016;4(8):e2] [AJSM 2014; 42(12): 3016]

Answer 268

1. Joint line tenderness
2. Pain in deep knee flexion
3. Positive McMurray test
4. Effusion
5. Locking
6. Giving way

Question 269

What are the MRI signs indicative of a meniscal root tear?

[JBJS REVIEWS 2016;4(8):e2]

Answer 269

1. Radial tear of the meniscal root on axial imaging
2. Truncation sign
   * Vertical linear defect in the meniscal root on coronal imaging
3. Ghost sign
   * Increased signal in the meniscal root on sagittal sequences
4. Meniscal extrusion >3 mm outside the peripheral margin of the joint on coronal imaging
5. Ipsilateral tibiofemoral compartment bone marrow edema and insufficiency fractures are commonly noted in the presence of posterior meniscal tears

Question 270

What meniscal root has the highest incidence of tears?

[JBJS REVIEWS 2016;4(8):e2]

Answer 270

Posterior root of the medial meniscus

• Least mobile of all roots

Question 271

What is the classification of meniscal root tears?

[Arch Bone Jt Surg. 2018; 6(4): 250-259.]

Answer 271

LaPrade classification

• Type I
  
  • Partial root tear
• Type II
  
  • Complete radial root tear
• Type III
  • Complete root tear + bucket handle tear
• Type IV
  
  • Oblique tear into root attachment
• Type V
  
  • Root avulsion fracture

Question 272

What are the indications for nonoperative and operative management of meniscal root tears?

[JBJS REVIEWS 2016;4(8):e2]

Answer 272

Nonoperative

• Sedentary lifestyle
• Extensive medical comorbidities
• Advanced signs of osteoarthritis
  • Outerbridge grade 3 or 4
• Joint-space narrowing
• Marked varus malalignment (>5°)
• Chronic, degenerative, irreparable tears

Operative

• Healthy individuals
• Minimal or no degenerative changes
  
  • Outerbridge grade 1 or 2
• Minimal to no joint-space narrowing
• Normal mechanical alignment
• Intact cruciate ligaments

Question 273

What are the indications for meniscal repair vs. partial meniscectomy in context of a root tear?

[JBJS REVIEWS 2016;4(8):e2]

Answer 273

1. Partial meniscectomy

• Chronic tears with advanced degenerative changes
  
  • Outerbridge grade 3 or 4

2. Meniscal root repair

• Acute tears
  
  • Goal of preventing arthritis
• Chronic tears with no or little articular cartilage wear
  • Outerbridge grade 1 or 2
  • Goal of symptomatic relief

Question 274

What is the goal of operative treatment for a meniscal root tear?

[JBJS REVIEWS 2016;4(8):e2]

Answer 274

Restore an anatomical attachment of the meniscal root to bone that is capable of converting axial weight-bearing loads into hoop stresses

• Thereby improving symptoms and function and ultimately preventing or delaying onset of degenerative changes

Question 275

What are the two main meniscal root repair techniques?

[JBJS REVIEWS 2016;4(8):e2]

Answer 275

1. Transtibial pullout repair

• Anatomical position of the meniscal root is identified, debrided, and prepared for repair
• An ACL tibial drill guide is utilized to drill a guide pin or a retro-cutting reamer into position through a small incision at the anteromedial aspect of the proximal aspect of the tibia
• # 2 nonabsorbable sutures are passed through the substance of the torn meniscal root with a suture-passage device
• Suture limbs are shuttled through the transtibial tunnel, tensioned, and fixed with use of whatever fixation construct the surgeon prefers with the knee in 30° of flexion
  • Typically a cortical button or screw and washer
    
    2. Suture anchor repair
• Utilizes accessory posteromedial and posterolateral portals
• Under arthroscopic visualization, the anatomical position of the meniscal root is identified, debrided, and prepared for repair
• A double-loaded suture anchor is inserted at the meniscal root site and suture passage is performed with use of a suture lasso through the accessory portal or with use of a rotator cuff-type suture-passage device through the anteromedial or anterolateral portal
• Once passed, the suture limbs are tied arthroscopically with the knee in 30° of flexion, with the arthroscopic knots being kept posterior, away from the articular surfaces of the affected compartment

Question 276

What are the complications associated with meniscal root repair techniques?

[AJSM 2014; 42(12): 3016]

Answer 276

1. Transosseous fixation

• Bone tunnels may interfere with concomitant ligament reconstruction
• Risk of suture abrasion within bony tunnel
• Risk of creep in the suture
  
  • Decreases strength of repair
    
    2. Suture anchor repair
• Anchor pullout
• Technically difficult

3. Other

• Retear and progression of arthritis
• Infection
• Arthrofibrosis
• DVT
• Iatrogenic injury to cruciates
• Iatrogenic injury to posterior neurovascular structures

Question 277

What features differ between a discoid meniscus and a normal meniscus?

Answer 277

1. Thicker
2. Less peripheral vascularity
3. Cover a larger surface area of the tibial plateau (may cover entire plateau - “true disc”)
4. Decreased collagen fibers in a more disorganized circumferential arrangement
5. Intrameniscal mucoid degeneration

Question 278

What is the most common classification of discoid menisci? [JAAOS 2017;25:736-743]

Answer 278

1. Watanabe
2. Type I - stable, complete discoid meniscus (most common)
3. Type II - stable, incomplete discoid meniscus (covers ≤80% of plateau)
4. Type III - unstable Wrisberg variant (lacks posterior meniscotibial attachment; only has the meniscofemoral ligament of Wrisberg)

Question 279

What are the classic symptoms of a torn or unstable discoid meniscus?

Answer 279

1. Knee pain, popping, snapping, and a lack of terminal extension

Question 280

what are the radiographic features of discoid meniscus? [JAAOS 2017;25:736-743] [Knee Surg Relat Res 2016;28(4):255-262]

Answer 280

1. Squaring of the lateral femoral condyle
2. Cupping of the lateral tibial plateau
3. Widening of the lateral joint space up to 11 mm
4. Hypoplastic lateral tibial spine

Question 281

What are the MRI features of discoid meniscus? [Orthop Clin N Am 46 (2015) 533-540] [JAAOS 2017;25:736-143]

Answer 281

1. Transverse meniscal diameter > 15 mm between the free margin and the periphery of the body on a coronal view
2. Continuity between the anterior and posterior horns of the menisci (i.., bow tie sign) noted on at leas three consecutive 5-mm-thick sagittal slices
3. Enlarged “bow-tie” appearance on a single sagittal slice
4. Ratio of the minimal meniscal width to maximal tibial width (on the coronal MRI slice) of more than 20%

Question 282

What are the indications for nonoperative and operative management of discoid menisci? (JA AOS 2017.25.736-743)

Answer 282

1. Nonoperativea. Asymptomaticb. Discoid menisci identified incidentally at arthroscopy should not be treated
2. Operative
   1. Symptomatic

Question 283

what is the surgical technique for managing a discoid menisci

Answer 283

1. arthroscopic saucerization with rim preservation +/- stabilization
   
   1. preserve meniscus with intact 6-8mm peripheral rim of meniscal tissue is recommended
   2. stabilization is added for watanabe type III

Question 284

What are the most common locations for OCD lesions in the knee?

[Sports Med Arthrosc Rev 2016;24:44–49]

Answer 284

1. 70% - posterolateral aspect of the medial femoral condyle
2. 15% - inferior central aspect of the lateral femoral condyle
3. 5-10% - inferior medial aspect of the patella
4. <1% - trochlea

Question 285

what is the incidence of bilateral OCD of the knee?

Answer 285

2.7-30%

Question 286

What other pathology is associated with an OCD lesion of the lateral femoral condyle?

Answer 286

Discoid lateral meniscus

Question 287

What are the two broad categories of OCD?

[Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 287

1. Juvenile (open physis)
2. Adult (closed physis)

Question 288

What is Wilson’s sign (Knee OCD)?

[Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 288

The knee is extended from 90-30 while internally rotating the tibia

• Positive = reproduction of symptoms with internal rotation and relief with external rotation

Question 289

What are MRI features of an unstable OCD lesion?

[Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 289

1. High-signal intensity behind the lesion
2. Cystic area beneath the lesion
3. High-signal intensity through the articular cartilage
4. Focal articular defect

Question 290

what are radiographic, mri and arthroscopic classifications of OCD of the knee

Answer 290

radiograhpic - berndt and harty
- stage 1 - small area, compression of subchondral bone
- stage 2 - partially detached OCD fragment
- stage 3 - fully detached OCD fragment, still in underlying crater
- stage 4 - compete detachment/loose body

mri = di paola
type I - thickening of articular cartilage but no break
type II - breached articular cartilage, low signal rim behind fragment indicating attachment
type III - breached articular cartilage, with high signal T2 changes behind fragment suggesting fluid around lesions
type IV - loose body and defect of articular surface

arthroscopic - rock studh group
6 arthroscopic categories
3 immobiles types
1. cue ball - no abnormality
2. shadow - cartilage is intact and suptly demarcated
3. wrinkle in the rug - cartilage is demarcated with a fissure, buckle and/or wrinkle

3 mobile types
1. locked door = cartilage fissuring at periphery unable to hinge open
2. trapdoor = cartilage fissuring at periphery able to hinge open
3. crater = exposed subchondral bone defect

Question 291

What factors are predictive of poor prognosis in OCD lesions in the knee?

[Sports Med Arthrosc Rev 2016;24:44–49]

Answer 291

1. High signal line between the OCD lesion and underlying bone on T2-MRI (unstable)
2. Skeletal maturity (older age)
3. Larger lesion
4. Patellar and lateral femoral condyle OCD lesions
5. Cyst ≥1.3mm behind the lesion
6. abnormal surface cartilage
7. viability of the fragment
   
   1. can be determine on MRI post-gad T1 image with fat saturation - low signal compared epiphyseal bone suggests poor viability

Question 292

What is the classification of OCD lesion of the knee?

[Orthobullets]

Answer 292

Clanton Classification

• Type I - depressed osteochondral fracture
• Type II - fragment attached by osseous bridge
• Type III - detached non-displaced fragment
• Type IV - displaced fragment

Question 293

What are the indications for nonoperative management of an OCD lesion in the knee?

[Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 293

Stable lesion

Question 294

What is the protocol for nonoperative management?

[Bone Joint J 2016;98-B:723–9]

Answer 294

***No consensus

1. TTWB 4 weeks
2. Activity restriction (no running and sport) for 8 weeks
3. MRI at 12 weeks
   * If no improvement in symptoms = consider surgery
   * If symptoms resolved and MRI improved = progress activity with full return after 4 weeks
   * If symptoms improved but MRI is unchanged = continue activity restriction and repeat MRI in 12 months
   
   • If no improvement = surgery

Question 295

What are the indications for operative management of an OCD lesion in the knee?

[Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 295

1. Unstable lesion
2. Displaced lesion
3. Failure of nonoperative management
   * 6 months for juvenile, 3-6 months for adult
4. Symptomatic loose bodies

Question 296

What are the surgical options for OCD of the knee?

[Bone Joint J 2016;98-B:723–9] [Curr Rev Musculoskelet Med (2015) 8:467–475]

Answer 296

1. Stable symptomatic lesion

• Retrograde or transarticular drilling
  
  • Equivalent effectiveness

2. Unstable, nondisplaced
   * Internal fixation with bioabsorbable or metal pins, nails or screws
3. Unstable, nondisplaced with cyst
   * bone grafting and internal fixation
4. Unstable, displaced

• internal fixation of fragment
  
  • Fragment trimming due to hypertrophy

5. Unsalvageable fragment
   * Excision = small fragments (<2cm)
   * Microfracture
   * ACI/MACI
   * Osteochondral autograft or allograft
6. Consider osteotomy or patellar realignment to offload the lesion

Question 297

What are the indications and contraindications for articular cartilage repair and restoration procedures?

[JAAOS 2017;25:321-329]

Answer 297

Indications

• Outerbridge or International Cartilage Repair Society grade III or IV focal chondral or osteochondral defects

Contraindications

• Inflammatory arthritis
• Lower grade lesions
• Inability to comply with postoperative protocol

Question 298

What are the general surgical recommendations for articular cartilage lesions based on size of defect?

[Sports Health 2015; 8(2):153]

Answer 298

<2cm² – microfracture OR OATs

• OATS better in higher demand patient

2-4cm² - OATs or ACI

>4cm2 – ACI or osteochondral allograft (better in defects with bone loss or deformity)

Question 299

What is the technique for microfracture of articular cartilage lesions?

[JBJS 2010;92:994-1009] [JAAOS 2017;25:321-329]

Answer 299

1. Create a contained lesion with stable shoulders

• Remove the calcified cartilage layer at the base of the lesion
• Prepare the channels by perforating the subchondral bone with a 45° awl approx. 3-4mm in depth
  
  • Fat droplets from the marrow should be visualized, blood should be visualized with water off
  • Space the channels 3-4mm apart
• Allows for clot formation and migration of marrow-derived mesenchymal stem cells promoting fibrocartilage repair

2. Postoperative

• nonWB for 6 weeks with crutches
• CPM from 0-60° for 6 weeks, 6-8 hours per day
• Full ROM and closed chain exercises at 2 months
• Full return to activity at 3 months

Question 300

What are the advantages and disadvantages of microfracture for articular cartilage lesions?

[JBJS 2010;92:994-1009]

Answer 300

Advantages

• Technically straightforward
• Low cost
• Minimal morbidity

Disadvantages

• Fibrocartilage rather than hyaline cartilage
  
  • Results deteriorate over time

Question 301

What is the technique for autologous osteochondral transplantation (aka. Mosaicplasty, osteoarticular transfer system – OATS) for articular cartilage lesions?

[JAAOS 2017;25:321-329]

Answer 301

Multiple small autogenous osteochondral plugs are harvested from less weightbearing areas and transferred to fill a defect

• Plugs are approx. 10mm in depth, impacted in donor site to match the height of the adjacent cartilage
• Periphery of femoral condyles and intercondylar notch are donor sites

Question 302

What are the advantages and disadvantages of autologous osteochondral transplantation (OATS) for articular cartilage lesions?

[JBJS 2010;92:994-1009] [JAAOS 2017;25:321-329]

Answer 302

Advantages

• Hyaline cartilage transferred
• Less postoperative restrictions
• Single procedure

Disadvantages

• Limited availability of graft
• Donor site morbidity
• Different thickness and mechanical properties of cartilage from donor to recipient site
• Graft subsidence
• Dead space between grafts
• May require arthrotomy

Question 303

What is the technique for osteochondral allograft transplantation for articular cartilage lesions?

[JBJS 2010;92:994-1009]

Answer 303

Cadaver graft consisting of intact, viable articular cartilage and subchondral bone is transferred in the defect

Question 304

What are the advantages and disadvantages of osteochondral allograft transplantation?

[JBJS 2010;92:994-1009]

Answer 304

Advantages

• No donor site morbidity
• Can fill large defects
• Hyaline cartilage transferred
• Single stage
• Can achieve precise surface architecture
• Eliminates dead space

Disadvantages

• Limited graft availability
• High cost
• Risk of immunological reaction and disease transmission
• Possible incomplete graft incorporation
• Technically demanding machining and sizing the allograft

Question 305

What are the indications for osteochondral allograft of the knee?

Answer 305

• Young active patient
• Posttraumatic osteochondral defects
• Osteonecrosis
• Osteochondritis dissecans
• Large (≥2 cm2) focal defects
• Previous cartilage repair failure
• Patellofemoral joint cartilage lesion

Question 306

What are the contraindications for osteochondral allograft of the knee?

Answer 306

• Relative
  
  • BMI >35
  • Concomitant ligament or meniscal injury
  • Uncorrectable malalignment of the knee joint
  • Inflammatory arthritis
  • Smoking or corticosteroid use
• Absolute
  
  • Advanced osteoarthritis (bipolar lesions)
  • Poor surgical candidate
  • Chronic posttraumatic defect

Question 307

what imaging is required for preop planning of osteochondral allograft of the knee?

Answer 307

• radiographs
  
  • routine WB with sizing markers
  • full length alignment films
• MRI
  
  • assess for concomitant pathology
  • assess lesion size and location

Question 308

What is the technique for autologous chondrocyte implantation (ACI)?

[JBJS 2010;92:994-1009] [JAAOS 2017;25:321-329]

Answer 308

Two stage procedure

• First for tissue harvest
  
  • 100-300mg of articular cartilage from nonWB surface
  • Sent for culture and expansion of donor chondrocytes
• Second for cell implantation into the prepared recipient site
  
  • 3-8 weeks after the first stage
  • Cells are injected beneath a collagen membrane or periosteal patch sutured over the defect

Question 309

What are the advantages and disadvantages of ACI?

[JBJS 2010;92:994-1009] [Sports Health 2015; 8(2):153]

Answer 309

Advantages

• Hyaline cartilage produced

Disadvantages

• Two stage procedure
• Technically demanding
• High cost
• Requires arthrotomy

Question 310

What is difference between ACI and matrix-associated chondrocyte implantation (MACI)?

[JBJS 2010;92:994-1009]

Answer 310

Chondrocytes are incorporated into a collagen membrane eliminating the need for periosteal harvest and makes for a more even cell distribution on the membrane

Question 311

What are the standard and accessory portals for knee arthroscopy?

Answer 311

1. Standard

• Anterolateral
• Anteromedial

2. Accessory [JBJS 2006; 88(4):110]

• Posteromedial
  
  • Location
    • Soft spot between MCL, medial head of gastrocs and semitendinosus tendon
  • Technique
    
    • Perform with knee at 90
    • Knee joint distended
    • Direct visualization with transcondylar notch view
    • Soft spot is localized with a spinal needle
    • Superficial incision
    • Blunt dissection with hemostat and joint capsule is penetrated
  • Risk
    
    • Saphenous nerve (sartorial branch)
• Posterolateral
  
  • Location
    
    • Soft spot between LCL, lateral head of gastrocs, posterolateral tibial plateau and biceps femoris
  • Technique
    
    • Perform with knee at 90
    • Knee joint distended
    • Direct visualization with transcondylar notch view
    • Soft spot is localized with a spinal needle
    • Superficial incision
    • Blunt dissection with hemostat and joint capsule is penetrated
  • Risk
    
    • Common peroneal nerve
• Posterior transeptal portal
  
  • Location
    
    • Involves resection of the posterior septum from the posterolateral portal to enter the posteromedial compartment under visualization from the posteromedial portal
      
      • Posterior septum is a triangle-shaped two-layer synovial reflection that divides the posterior aspect of the knee into posteromedial and posterolateral compartments
      • Bounded by the posterior cruciate ligament anteriorly, the posterior portion of the femoral intercondylar notch superiorly, and the posterior aspect of the capsule posteriorly
  • Risk
    
    • Popliteal artery (inferiorly) and middle geniculate artery (superiorly)

Question 312

What are ways to control intraoperative bleeding during arthroscopy?

[CORR course]

Answer 312

1. Increased pump pressure
2. Reduce outflow suction
3. Asd epinephrine to fluid
4. Controlled hypotension (anaesthesia)
5. Tourniquet
6. Drive arthroscope to bleeding source
7. Cautery
8. TXA

Question 313

What are the avulsion fractures found at the knee?

Answer 313