Ulnar Carpal Instability is a condition in which the normal mechanics of the wrist is disrupted due to misalignment of the three bones on the pinky side of the wrist (the ulna, lunate and triquetrum). Falling on an outstretched hand with a twisting motion causes this injury to the many ligaments on the medial side of the wrist.

Ulnar Carpal Instability manifests itself in chronic pain, stiffness, weakness and a possible clicking noise. Collision sports, BMX and skateboarding (full pipes more than street courses) are often implicated.

Mild cases can be treated by rest, immobilization and anti-inflammatory medication, while severe cases may necessitate cortisone injection and arthroscopically assisted reconstructive surgery.