- Compound joint
- Femoral condyles and Tibial articular surfaces
- Pattello-femoral joint
- Menisci:
- Medial / Lateral
- Ligaments:
- Cruciate: ACL, PCL
- Collateral: MCL, LCL
© 1998 Nucleus Communications, Inc. - Atlanta www.nucleusinc.com
Knee Stability
The knee’s bony structure is unstable. Knee stabilization depends on:
- Strong capsule
- Intra-articular ligaments
- Extra-articular ligaments
- Muscles around the knee
- Menisci add to stability
Valgus Stress Resistance
Valgus stresses are resisted by:
- Pes anserinus
- Medial collateral ligament
Varus Stress Resistance
Varus stresses are resisted by:
- Iliotibial tract
- Lateral collateral ligament
Anteroposterior & Rotatory Stabilizers
- Anterior cruciate ligament (ACL)
- Posterior cruciate ligament (PCL)
- Both also resist excessive valgus/varus angulation
Cruciate Ligaments
Anterior Cruciate Ligament (ACL)
- Tibial attachment:
- Between intercondylar eminence
- Femoral attachment:
- Posteromedial aspect of lateral femoral condyle
Posterior Cruciate Ligament (PCL)
- Tibial attachment:
- Tibial sulcus below articular surface
- Femoral attachment:
- Anterolaterally on medial femoral condyle
Meniscus Anatomy
Medial Meniscus
- Shape: C-shaped
- Vascularization: Peripheral 20-30% is vascular
Lateral Meniscus
- Shape: Round shaped
- Vascularization: Peripheral 10-25% is vascular
Function of Menisci
- Deepen the articular surfaces of tibial plateau
- Role in:
- Controlling rolling & gliding actions
- Load distribution: Without menisci, load on articular cartilage increases five folds
- Stability (wedge effect)
Distribution of weight by the meniscus
©MMG 2001
Knee Injury Statistics
- Most commonly injured joints
- Most common injuries:
- ACL tears: 46%
- MCL tears: 29%
- ACL + MCL tears: 13%
- Complex injuries: 6%
- PCL tears: 4%
- LCL tears: 2%
Knee Ligament Injuries Distribution:
- ACL: 46%
- MCL: 29%
- ACL + MCL: 13%
- Complex: 6%
- PCL: 4%
- LCL: 2%
Legend:
- ACL: Anterior Cruciate Ligament
- PCL: Posterior Cruciate Ligament
- ACL+MCL: Combined ACL and MCL injuries
- LCL: Lateral Collateral Ligament
- MCL: Medial Collateral Ligament
- COMPLEX: Complex multi-ligament injuries
