MCL Knee Injury (Medial Collateral Ligament)
The medial collateral ligament (MCL) runs along the inner side of the knee, providing stability against forces that push the knee outward. MCL injuries are common in contact sports (rugby, AFL, soccer) and skiing — usually from a blow to the outside of the knee or a valgus (knee-caving) force.
The good news: the MCL has an excellent blood supply and remarkable capacity to heal. The majority of MCL injuries — even complete tears — are managed successfully without surgery.
Grading
- Grade 1: Ligament sprain, fibres intact, minimal swelling, able to bear weight
- Grade 2: Partial tear — significant pain, swelling, instability with stress testing
- Grade 3: Complete rupture — instability on valgus stress; however, usually still managed conservatively unless combined with other ligament injuries (e.g. ACL)
Symptoms
- Pain on the inner side of the knee
- Swelling along the medial joint line
- Tenderness on palpation of the ligament
- Pain or instability when the knee is pushed inward
- Stiffness and difficulty fully bending or straightening the knee
- Bruising below the knee (grades 2–3)
Treatment
Phase 1: Acute Management (Days 1–5)
- Ice, compression and elevation
- Protected weight-bearing (crutches for grade 2–3)
- Hinged knee brace for grade 2–3 to protect healing while maintaining movement
- Gentle range of motion exercises within pain tolerance
Phase 2: Progressive Loading (Weeks 2–6)
- Quadriceps and hamstring strengthening
- Hip strengthening to reduce valgus forces at the knee
- Proprioception and balance training
- Gradual return to straight-line activity and then cutting
Phase 3: Return to Sport
- Sport-specific agility and reactive movement
- Objective strength and stability testing
- Protective bracing strategies for return to contact sport
Combined Injuries
MCL injuries sometimes co-occur with ACL tears and meniscus injuries. A thorough assessment is essential to identify associated damage, as combined injuries require different management and longer timelines.
