Collateral ligament sprain: what to know

Collateral ligaments help prevent excessive sideways movement, most often at the knee. An inward or outward force, a collision, or a sudden turn can strain these fibres. Pain is usually localized to the affected side, with tenderness, swelling, and reduced confidence during movement. A mild injury may leave the joint stable, while a more substantial tear can cause looseness or difficulty bearing weight. Other injuries can occur at the same time, so the mechanism and examination guide treatment.

Stop the activity that caused pain and protect the joint from twisting or impact. Use comfortable, gentle movement rather than complete inactivity, and elevate the area when swollen. A wrapped cold pack may help after a recent injury. A clinician may suggest support such as [Splinting](/treatments/trauma-and-fracture-care/splinting/). [Physiotherapy](/treatments/physiotherapy-and-rehabilitation/physiotherapy/) builds motion, strength, and control as healing progresses. [Kinesiology Taping](/treatments/physiotherapy-and-rehabilitation/kinesiology-taping/) can be considered as supplementary support.

Arrange prompt medical assessment if the joint feels unstable, you cannot use the limb normally, swelling is substantial, or pain followed a forceful collision. Seek urgent help for deformity, a cold or discoloured hand or foot, new numbness, or severe pain that escalates. Ongoing tenderness or repeated giving-way also deserves review because a combined injury may need a different plan.

Which collateral ligament is affected, and is the joint stable? Would a brace or imaging help? Which exercises and activities are appropriate at each stage of recovery?