Radial collateral ligament thumb pain: what to know

The radial collateral ligament supports the side of the thumb's metacarpophalangeal joint, where the thumb meets the hand. A sudden sideways force, a fall, or forceful gripping can stretch or tear it. Pain may be focused on the joint's outer side, with tenderness, swelling, bruising, or difficulty pinching. Pain at the thumb side of the wrist can have a different source, such as De Quervain's Tenosynovitis, so the exact location and movement that triggers symptoms matter.

Stop activities that force the thumb sideways or require a strong pinch. Keep the thumb supported in a comfortable position with a suitable splint if one has been recommended, and use a wrapped cold pack for short periods to limit swelling. Do not force painful movements or repeatedly test the joint. A clinician can check stability and decide whether imaging, a period of immobilisation, or guided exercises is appropriate.

Seek prompt medical assessment after a clear injury if the thumb looks crooked, feels unstable, becomes numb or unusually cold, or cannot bend or straighten. Arrange care soon for marked swelling, bruising, or pain that interferes with gripping. Persistent symptoms without an obvious injury also deserve an examination because ligament, tendon, joint, and bone problems can overlap.

Ask which structure is tender, whether the joint is stable, and whether an X-ray or other scan is needed. You can also ask how long support should be worn, which movements to avoid, and when thumb exercises or physiotherapy should begin.