Occurs when excessive valgus stresses or external rotation forces are placed on the knee joint.
The most common symptom is medial-sided knee pain above or below the joint line. Patients are usually able to walk.
Diagnosis and grading is primarily made with history-taking and physical examination.
Most patients are treated non-operatively.
Prognosis for isolated medial collateral ligament injuries is good. Most patients return to sports within 3 to 6 weeks and to pre-injury levels within 3 months.
Combined multi-ligament and chronic medial collateral ligament injuries often require operative intervention.
The medial collateral ligament (MCL) is a supporting structure on the medial part of the knee joint. Its primary function is to resist valgus (twisting outwards away from the mid-line) and external rotation forces of the tibia in relation to the femur. The mechanism for MCL injury is typically a large valgus and/or external rotation force that is suddenly placed on the knee joint. Injuries to the MCL range in severity from a few torn fibres to complete disunity of the ligament.
History and exam
Key diagnostic factors
- presence of risk factors
- injury due to excessive or repetitive valgus loading of MCL
- medial knee pain
- joint effusion
- laxity on valgus stress testing
Other diagnostic factors
- audible pop or tearing sensation at time of injury
- difficulty walking
- instability symptoms of knee
- mechanical knee symptoms
- knee deformity
- positive anterior drawer test
- positive posterior drawer test
- positive Lachman's test
- positive pivot shift test
- joint line tenderness
- chronic pain
- participation in activities involving valgus stress at the knee joint
- age 20 to 35 years
- age 55 to 70 years
- weak muscles that cross the medial aspect of knee
1st investigations to order
- plain x-rays of knee
- stress x-rays of knee
Investigations to consider
- MRI of knee
- diagnostic ultrasound
isolated grade I injury
isolated grade II injury
isolated grade III injury
MCL + anterior cruciate ligament (ACL) combined injury
MCL + non-anterior cruciate ligament (ACL) combined injury
persistent high-grade valgus laxity after ≥3 months
- Medial meniscus tear
- Soft tissue contusion of the medial knee
- Tibial plateau fracture
- Management of anterior cruciate ligament injuries: evidence-based guideline
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