What the MCL does
The MCL is a broad band that connects the thigh bone to the shin bone on the inner side of the knee. It resists forces that push the knee inwards (valgus stress) and helps control rotation. It has a good blood supply, which is why it heals much better than the anterior cruciate ligament.
Part of the MCL is connected to the medial meniscus, so the two are sometimes injured together; see meniscus tear.
How MCL injuries happen
- A blow to the outside of the knee, as in a tackle in football or rugby.
- Skiing falls where the ski tips spread apart (snowplough position).
- Sudden changes of direction, cutting and pivoting.
- Landing awkwardly from a jump with the knee falling inwards.
- Wrestling, judo and other contact sports.
Symptoms by grade
- Grade 1: the ligament is stretched with microscopic tears. Tenderness on the inner knee, little or no swelling, the knee is stable.
- Grade 2: partial tear. More pain and swelling, some looseness when the knee is stressed, difficulty with twisting and sport.
- Grade 3: complete tear. Pain may be surprisingly mild, but the knee feels unstable and gives way when pushed inwards. Often combined with other injuries.
For other causes of pain on the inner side of the knee, see pain on the inside of the knee.
How it is diagnosed
A physiotherapist or doctor examines the knee and gently pushes it inwards with the knee straight and slightly bent to assess how much the ligament opens. They also check the ACL, meniscus and kneecap.
X-rays may be used to rule out a fracture, and an MRI is helpful when a grade 3 tear or other injuries are suspected, or when recovery is slower than expected.
What to do in the first days
- Protect the knee and avoid twisting and contact.
- Use ice for 15 to 20 minutes several times a day.
- Compress and elevate the leg to control swelling.
- Use crutches if walking is painful.
- Start gentle bending and straightening as pain allows.
Avoid heat, alcohol and massage on the injured area in the first 48 to 72 hours.
Bracing
For grade 2 and grade 3 injuries, a hinged knee brace protects the ligament from inward forces while allowing the knee to bend. It is usually worn for 2 to 6 weeks, depending on the grade and the person’s progress.
Some athletes continue to wear a brace when returning to contact sport during the first season.
Physiotherapy and rehabilitation
- Early phase: reduce swelling, restore full straightening and bending, and activate the quadriceps.
- Strength phase: progressive exercises such as squats, step-ups, lunges and bridges, with the knee kept in line with the foot.
- Control phase: balance, hopping and landing drills.
- Return to sport: running, cutting and sport-specific drills before full training and matches.
Taping can give extra support and confidence; see KT tape for the knee. Swelling after activity is a sign to slow the progression; see joint effusion.
Recovery time
- Grade 1: 1 to 3 weeks.
- Grade 2: 3 to 6 weeks.
- Grade 3: 6 to 12 weeks, longer if other structures are injured.
Return to sport depends on full movement, good strength compared with the other leg, no swelling and confidence with cutting and pivoting, not just on time.
When surgery is needed
Surgery is rarely needed for an isolated MCL tear. It is considered when the MCL is torn together with the ACL or other ligaments, when the ligament is torn off the bone in a way that will not heal, or when the knee remains unstable after a full course of rehabilitation.
In combined ACL and MCL injuries, the MCL is often allowed to heal first before ACL reconstruction.
When to seek medical advice
- You heard a pop and the knee swelled quickly.
- The knee gives way or feels very unstable.
- You cannot put weight on the leg.
- The knee locks or will not straighten.
- Numbness, coldness or colour change in the foot.
Key points to remember
- The MCL stabilises the inner side of the knee and heals well.
- Most MCL injuries are treated without surgery.
- A hinged brace and progressive physiotherapy are the mainstays of treatment.
- Recovery ranges from 1 to 12 weeks depending on the grade.
Questions about MCL injuries
These answers are general information and do not replace an examination or individual medical advice.
Can you walk with a torn MCL?
Usually yes, especially with grade 1 and 2 injuries. Crutches and a brace help with more severe tears.
Does a torn MCL heal on its own?
Yes. The MCL has a good blood supply and most tears heal without surgery.
What does an MCL tear feel like?
Pain and tenderness on the inner side of the knee, swelling and, in severe tears, a feeling of instability.
Should I wear a brace for an MCL sprain?
A hinged brace is recommended for grade 2 and 3 injuries; grade 1 often does not need one.
How do I know if my MCL tear is grade 1 or 2?
An examination of how much the knee opens when pushed inwards determines the grade.
Can I play sport with an MCL injury?
Only after full movement, strength and confidence return, usually with a physiotherapist’s guidance.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.