Ch 4 - MSK: Knee Pathology Flashcards by Dr B

What are meniscal injuries associated with?

Cutting maneuvers

Tibial rotation w/ knee partially flexed in WB

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What sports are medial meniscal injuries associated with?

Football

Soccer

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What sports are lateral meniscal injuries associated with?

Squatting

Wrestling

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What is the clinical presentation of an acute meniscal tear?

– Pop after an incident
– May cause true locking
– Effusions ~24 hours
– Knee stiffness

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What is the most common MOI for posterior horn meniscal tears?

Valgus and ER

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What is the clinical presentation of a degenerative meniscal tear?

– Minimal trauma
– >40 yo
– Impingement episodes may be minimal

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What is seen on physical exam in meniscal injury?

Dec ROM
Effusion limits flexion
Meniscal fragment limits extension
Medial/lateral joint line tenderness

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What is the gold standard for diagnosing meniscal tears?

MRI
– Sagittal views will best show the anterior and posterior meniscal horns
– Coronal views are the best views for the meniscal body

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How do meniscal tears appear on MRI?

Line of increased signal extending from articular surfaces

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What is the treatment of an inner 2/3 meniscal injury?

Surgical resection because of avascularity and resultant poor tissue healing
WBAT 1-2 day post op

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What is the treatment of an outer 1/3 meniscal injury?

Repaired due to better vascular supply
NWB 4-6 weeks
Strengthening at 6 weeks

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What is the most common ligament injured in athletics?

ACL
Soccer
Football
Downhill skiing

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What is the MOI for ACL injury?

Cutting, deceleration, and hyperextension of the knee
Valgus force to a flexed and rotated knee
Noncontact injuries MC

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What is the terrible triad?

ACL, MCL and medial meniscus injury

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What is the clinical presentation of an ACL injury?

– Sudden pop, anterior knee pain w/ posterior lateral joint line pain
– Instability of the knee
– Swelling ~24 hours, and significant effusion

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What is seen on exam in an ACL injury?

– Effusion
– Tenderness is variable
– +/- anterior drawer test
– Lachman’s test may be positive or can yield a false negative in approximately 10% of cases. It is examiner dependent and also influenced by muscle guarding.

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What can be seen on X-ray in ACL injury?

Avulsion fx of tibial insertion of the ACL or the lateral capsular margin of the tibia

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What is the accuracy of MRI to detect ACL tear?

85-90%

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What is the initial treatment for ACL injury?

Partial WB, ice, and compression are used while evaluation is ongoing

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What is the treatment after ACL reconstruction surgery?

– Partial WB
– Flex ROM 1st 2 wks
– Progress to closed chain kinetics
– Avoid open chain exercises
– Resistive exercises b/w 0° and 45° flex avoided 3 to 6 mo
– Lenox Hill derotation orthosis controls knee axial rotation, AP and medial–lateral control
– Sports-specific exercises 6 to 12 wks
– Complete rehab in 6 mo-1 yr w/ max ROM, strength, and agility

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What is the MOI of a PCL injury?

MCC is impact to the front of the tibia with the knee flexed
Athletics: hyperflexion

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What is the clinical presentation of a PCL injury?

– (+/-) pop
– Swelling inc ~24 hr
– Impaired extension
– (+/-) pain w/ WB

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What is seen on exam in PCL injury?

– Effusion
– Popliteal tenderness
– (+/-) Posterior drawer test and sag tests

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What can be seen on x-ray with PCL injury?

Avulsion

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What is the treatment of a PCL injury?

* Surgical repair if ligament is avulsed w/ tibial fragment | * Quadriceps strengthening

What is the most common injured ligament of the knee?

MCL injury

What is the MOI of MCL injury?

* Football and skiing * Impact force to the lateral knee * Sustained valgus force

What is the clinical presentation of a MCL injury?

– Pop – Medial knee pain – Complete tears may allow walking and running after initial pain – Knee stiffness

What is seen on exam in MCL injury?

– Medial swelling/ tenderness – Min effusion – Medial instability on valgus stress testing – Opening of 5 to 8 mm compared to the opposite side may indicate a complete tear – Instability in slight flex 30° specific for MCL injury – Instability in full extension: MCL and posterior capsule injury

What can be seen on x-ray in MCL injury?

Epiphyseal fx

When would MRI be useful in MCL injury?

Delineate the MCL tear and investigate associated injuries

What is the treatment for MCL injury?

* Isolated tears treated conservatively * Knee brace * Strengthening and stability * Tear with concomitant injuries may require surgical intervention

What is the MOI of LCL injury?

Knee dislocation

What other injuries can be associated with LCL injury?

Vascular Cruciate Peroneal nerve Posterior lateral corner instability

When does the ITB slide over the lateral femoral condyle?

During flexion and extension

Where does the ITB insert?

Gerdy’s tubercle on the lateral tibia

What leads to ITB dysfunction?

Inflexibility of the ITB | Adductor/abductor muscle imbalances

What is the clinical presentation of ITB syndrome?

* Pain over the lateral femoral condyle and/or Gerdy’s tubercle * Worse by walking or jogging * Better with running

How do patients adapt to ITB syndrome?

ER hip IR lower leg Pronating foot

What is the treatment for ITB syndrome?

* Stretching the ITB, hip flexors, and gluteus max * Strengthening the hip abductors, gluteus max, and TFL * Orthotics may be helpful and foot over-pronation must be corrected * Injection at the lateral femoral condyle in resistant cases

What increases weight bearing to patellofemoral joint?

– Knee flexion – Walking: 0.5x BW – Stairs: 3.3x BW – Squatting: 6.0x BW

What helps to prevent patellar subluxation?

Lateral lip of patellar surface of femur

What can increase risk for lateral patellar subluxation?

``` Less prominent lateral lip Inc genu valgum Vastus medalis weakness Tibial external torsion Shallow lateral femoral condyle Laterally attached infrapatellar tendon on tubercle ```

What can increase risk for medial patellar subluxation?

Increased genu varum

What is the clinical presentation of a patellar subluxation?

* Displaced medially or laterally * Knee buckles * Pain at peripatellar region * (+/-) effusion * (+/-) vastus medialis wasting * Full extension * Reset at 25° to 30° flexion

What imaging should be done for patellar subluxation?

– AP view: patellar position over the sulcus – Lateral view: patellar height; done at 45° knee flexion and in full extension – Sunrise (tunnel) view: patellofemoral articulation and femoral condyle height

What is the most common cause of anterior knee pain?

Patellofemoral pain syndrome

What is a patella alta?

High-riding, laterally shifted patella due to vastus lateralis tightness and relative medial weakness, causing tracking dysfunction

What is a patella baja?

Low patella | Less common and may indicate quadriceps rupture

What is a squinting patella?

Patellar IR

What is a frog eye's patella?

Patellar ER

What can predispose to patellofemoral pain syndrome?

* Tight hip flexors or abductors can alter gait and cause symptoms * Inc Q angle * Tight hamstrings can increase patellofemoral loading

What factors can increase Q angle?

Internal torsion of Femur Lateral insertion of the infrapatellar tendon on the tibia Genu valgum

What are treatments for patellofemoral pain syndrome?

VMO/hip abductor strengthening Patellar taping/bracing Limit biking, jumping, squatting Bike fitting

What is chondromalacia patella?

Cartilage appears roughened or fibrillated on arthroscopy

What is plica syndrome?

Redundant fold of the synovial lining of the knee, which is susceptible to tearing as it passes over the condyles

Where does the synovial lining extend in the knee?

Infrapatellar fat pad medially around the femoral condyles | and under the quadriceps tendon above the patella and lateral to the lateral retinaculum

What is the clinical presentation of plica syndrome?

Anterior knee pain of insidious onset that can gradually increase with prolonged knee flexion or sitting, but is made worse by standing and extension

When can plica syndrome give the sensation of knee buckling?

When plica is trapped between patella and medial condyle

What activities are associated with patellar tendonitis (jumper's knee)?

Repetitive, high quadriceps loading: Jumping, squatting, kneeling, and climbing stairs

What is the most common location for patellar tendonitis (jumper's knee)?

Inferior pole of patella

What is the clinical presentation of patellar tendonitis (jumper's knee)?

* Pain on high impact activity * Pain may diminish during activity and become more apparent afterward * TTP over patellar tendon and inferior/superior patellar pole

What is Osteochondritis dissecans?

Localized AVN at the end of a long bone l/t formation of dead subchondral bone covered with articular hyaline cartilage

What is the cause of Osteochondritis dissecans?

Repetitive small stresses to subchondral bone that disrupt blood supply to that area of bone

What are potential locations of Osteochondritis dissecans?

``` Medial femoral condyle Distal femur Patella Elbow Talus Distal humerus ```

Who is affected by Osteochondritis dissecans?

Adolescents

What is the clinical presentation of Osteochondritis dissecans?

* Gradual onset of joint pain, effusion, buckling | * Loose body may cause locking

What can help relieve pain of Osteochondritis dissecans (patella)?

Walking with the foot rotated outward may relieve pain

How can the medial femoral condyle be palpated?

Knee flexed 90° with pressure directed medial | to the inferior pole of the patella

What is the treatment of Osteochondritis dissecans?

* Prior to fragmentation: rest and protected WB | * After fragmentation: surgical excision

What is the origin and insertion of popliteus?

Origin: lateral face of the lateral femoral condyle Insertion: triangular area in the posterior tibia

What does the popliteus do?

* IR of the tibia * Unlocks the knee by laterally rotating the femur * With the ACL, it limits anterior translation of the femur

What is the clinical presentation of popliteus tendonitis?

* Lateral knee pain during downhill activities and with excessive pronation * TTP anterior to LCL * Pain with legs in figure of four or cross-legged position

What orthotics can help with popliteus tendonitis?

Arch supports or medial heel wedges