Medial Collateral Ligament Injury of the Knee
Anatomy:
The MCL is attached to the medial epicondyle of the femur 3cm above the joint line and passes downward to attach to the anteromedial aspect of the tibia. It has a deep attachment to the medial meniscus. The posterior oblique ligament originates posterior to the superficial MCL fibres off the femoral condyle and inserts just below the joint line. It is intimately attached to the posterior horn of the medial meniscus. The MCL prevents excessive lateral tilting of the tibia during valgus stress.
It is the primary restraint to valgus stress and internal tibial rotation. It provides a secondary restraint to anterior tibial translation.
Investigations:
Plain films may show a femoral avulsion #, opening of the medial space on valgus stress views, soft tissue swelling or Pelligrini-Steida calcification in the chronic stage.
History:
Usually as result of valgus stress to a partially flexed knee.
MCL is the most commonly injured ligament about the knee. Concurrent meniscal injuries occur in 0-5% of isolated medial ligament injuries.
Grade I: Mild. Local tenderness over MCL, usually no swelling. Pain but no laxity (0-1mm) on stressing.
Grade II: Moderate. Marked tenderness with some swelling. Has laxity (5-9mm) but distinct endpoint.
Grade III: Variable pain (maybe less than grade II). Has tenderness and gross laxity (10-15mm) with no endpoint.
Treatment:
Managed conservatively- surgical repair has no better outcome than conservative for isolated MCL injury. ↑ severity equals ↑ period of rehab.
Grade I may take a few days to 2 weeks to rehab. It usually doesn’t warrant a hinge brace immobilization.
The early phase involves regular icing, massage +/- taping or bracing and isometric quadriceps and hamstring exercises. Progression to full weight-bearing occurs as pain settles.
The middle phase aims to achieve full pain-free range of motion and involves intermittent massage and stretching along with quadriceps drills (semi-squats, single leg step-downs), proprioceptive work (rebounder and wobble board), and cross training with straight line jogging, swimming and cycling. Post-exercise icing should be used as needed.
The final phase aims to achieve full strength and ROM and involves sport specific drills, agility work, and ongoing aggressive proprioceptive drills. Return to sport occurs when can perform all of the above and train pain-free.
Grades II-III may take 8-12 weeks, and can involve initial NWB period and immobilization in limited ROM brace.
One pattern of bracing for a high grade MCL injury suggests immobilization for 2 weeks in a hinge brace at 30-60º followed by 2 weeks at 10-90º of flexion.
The early phase involves regular icing, massage and isometric quadriceps and hamstring exercises. There is likely to be an initial NWB period with progression to PWB and FWB as tolerated.
The middle phase involves removal of the brace and intermittent massage and stretching along with quadriceps drills (semi-squats, single leg step-downs), proprioceptive work (rebounder and wobble board), and cross training with swimming and cycling. Progression from straight-line running is more gradual. Post-exercise icing should be used as needed.
The final phase aims to achieve full strength and ROM and involves sport specific drills, agility work, and ongoing aggressive proprioceptive drills. Return to sport occurs when can perform all of the above and train pain-free.
Lateral Collateral Ligament Tears of the Knee
Anatomy:
The LCL is attached to the lateral epicondyle of the femur 3cm and passes downward to attach to the head of the fibula. It is not attached to the lateral meniscus. Prevents excessive lateral tilting of the tibia during varus stress.
This is the primary restraint to varus stress. In full extension varus stability is also contributed to by the posterior capsule and posterolateral corner
History and Treatment:
Much less common than MCL tears. Stabilizers of the lateral side of the knee include the LCL, lateral capsule, popliteus, biceps femoris, and the ITB. Must consider avulsion of the biceps femoris tendon and remember that ACL tears can cause tenderness over posterolateral corner of the knee. Mild to moderate tears can be treated similarly to MCL tears.
Complete tears are often associated with other injuries and are associated with posterolateral instability of the knee. Usually requires acute surgery.