The short answer
The collateral ligaments help stabilise the knee from side to side. Injury can cause pain and a sense of instability at the inner or outer knee. Assessment checks whether the injury is isolated or part of a more complex pattern.
Understanding the problem
The MCL lies on the inner side and the LCL on the outer side. Different mechanisms and associated injuries can change treatment. A knee that feels unstable after trauma should not be repeatedly stress-tested at home.
Care and next steps
Some injuries are managed with support and rehabilitation, while others need specialist surgical discussion. The amount of protection and return-to-sport plan depend on stability and associated damage. An MCL injury should not automatically be treated like an ACL injury.
Prepare for your consultation
Explain the direction of impact and whether the knee twisted or buckled. Bring emergency notes and scans if available. Ask which ligaments are affected, what the brace is intended to protect and how long the current restrictions apply. Confirm which symptoms require earlier review and how rehabilitation will progress before you return to cutting or contact activity.
Common questions
Are all knee ligament injuries treated the same way?
No. The ligament involved, severity, stability and associated injuries influence treatment.
Medical sources & further reading
This patient education guide was approved for publication by Dr Shahrukh Khan on 11 September 2026. It cannot diagnose your symptoms or replace a personalised clinical assessment. Editorial policy · About the doctor.