Sports Medicine: Section 1 Knee

Question 1

ACL attachments and size

Answer 1

• Posteromedial aspect of lateral femoral condyle
• Anterior to intercondylar eminences
• 30 mm long
• 11 mm diameter

Question 2

ACL bundles

Answer 2

• Anteromedial
  
  • tight in flexion
  • anterior restraint
  • LACHMANS TEST
• Posterolateral
  
  • tight in extension
  • rotational restraint
  • PIVOT SHIFT TEST

Question 3

Blood supply to ACL and PCL

Answer 3

Middle geniculate artery & the fat pad

Question 4

PCL attachment and size

Answer 4

• Anterolateral medial femoral condyle
• Tibial sulcus
• 38 mm long
• 13 mm diameter

Question 5

PCL bundles

Answer 5

• Anterolateral
  
  • tight in flexion
• Posteromedial
  
  • tight in extension

Question 6

Meniscofemoral ligaments

Answer 6

• Origin: posterior horn of lateral meniscus (variable)
• Insertion: substance of the PCL
• HUMPHREY
  
  • anterior
• Wrisberg
  
  • posterior

Question 7

Superficial MCL attachments

Answer 7

• AKA tibial collateral ligament
• Origin: 3.2mm proximal and 4.8mm posterior from medial femoral epicondyle
• Insertion: proximal tibia deep to the Pes Anserinus (61.2mm distal to knee joint)

Question 8

Deep MCL attachments

Answer 8

• Capsular thickening
• Attaches to medial meniscus - Coronary ligaments

Question 9

LCL attachments

Answer 9

• AKA fibullar collateral ligament
• Origin: Posterior and superior to popliteus tendon insertion on lateral femoral epicondyle
• Insertion: fibullar head, MOST ANTERIOR STRUCTURE
• Behind axis of rotation –> tight in extension

Question 10

Posteromedial corner components

Answer 10

• Runs next to deep MCL
• Rotational restraint
• Three components
  
  1. Semimembranosus capsular thickenings
  2. Posterior oblique ligament
  3. Oblique popliteal ligament (post. capsule thickenings)

Question 11

Posterolateral corner components (PLC)

Answer 11

• Commonly injured in multiligamentour injuries
• Primary stabilizer of tibial external rotation
• 7 components
  
  1. Biceps femoris
  2. IT band
  3. Popliteus (inserts inferior, anterior to deep MCL)
  4. Popliteofibular ligament
  5. Lateral capsule
  6. Arcuate ligament
  7. Fabellofibular ligament

Question 12

Medial structures of the knee

Answer 12

• Layer I
  
  1. Sartorius
  2. Fascia
• Layer 2
  
  1. Superficial MCL
  2. Posterior oblique ligament
  3. Semimembranosus
• Layer 3
  
  1. Deep MCL
  2. Capsule

Question 13

Order of tendinous insertion:

proximal fibula

Answer 13

• Anterior to posterior
  
  1. LCL
  2. Popliteofibular ligament
  3. Biceps femorus

Question 14

Lateral structures of the knee

Answer 14

• Layer 1
  
  • IT tract
  1. Biceps femorus
  2. Fascia
• Layer 2
  
  1. Patellar retinaculum
  2. Patellofemoral ligament
• Layer 3
  
  1. Arcuate ligament
  2. fabellofibular ligament
  3. capsule
  4. LCL

Question 15

Medial meniscus

Answer 15

• Type I collagen (because it has some vascularity)
• “C” shaped
• Intermeniscal ligament anteriorily
• Coronary ligaments peripherally
  
  • Less mobile than lateral meniscus

Question 16

Lateral meniscus

Answer 16

• Type I collagen (because it has some vascularity)
• Circular shaped
• Intermeniscal ligament anteriorily
• Coronary ligaments peripherally
  
  • More mobile than medial meniscus

Question 17

Femoral condyles

Answer 17

• Lateral
  
  • Greater AP dimensions
  • Relativley straight
  • Terminal sulcus
  • Groove for poplitues
• Medial
  
  • Smaller AP dimensions
  • More curved –> screw home mechanism (ext rot of med tib plateau with full knee ext)

Question 18

Patellar restraints

Answer 18

• Restraints
  
  • Trochlea
  • Vastus medialis & lateralis
    
    • together form patellar retinaculum
  • Medial patellofemoral ligament

Question 19

Medial patellofemoral ligament (MPFL)

Answer 19

• Insertion: anterior and distal to adductor tubercle
  
  • also just superior to the superficial MCL
• Origin: medial border of patella (jxn of prox and middle third) & undersurface of VMO
• Resposible for 50% of total medial restraint

Question 20

Common causes of acute hemarthrosis

Answer 20

1. ACL tear (70%)
2. Patella dislocation
3. Osteochondral fracture
4. Isolated meniscal tear

Question 21

What two nerves need to be protected during meniscal repair?

Answer 21

1. Medial repairs
   
   1. Saphenous nerve - anterior to both the semiT and Gracilis. Posterior to inferior border of sartorius
2. Lateral repairs
   
   1. Peroneal nerve - posterior to biceps femoris

Question 22

Bakers cysts

Answer 22

• Related to meniscal pathology
  
  • Resolve with tx of primary cause
• Found between semimembranosus and medial head of gastroc

Question 23

Discoid meniscus

Answer 23

• Classification
  
  1. Incomplete
  2. Complete
  3. Wrisberg variant
• Mechanical sx of popping and locking
• Xray shows widened joint space, squaring of lateral femoral condyle
• MRI shows meniscus on 3 consecutive sagittal slices
• Tx with partial meniscectomy (saucerization)

Question 24

Bone bruises

Answer 24

• >50% of ACL injuries
• commonly near sulcus terminalis of LFC and posterolateral tibia
  *