Capitatehamate

Capitate-hamate coalition is a rare congenital anomaly characterized by a fusion or abnormal articulation between the capitate and hamate bones, two of the distal carpal bones in the wrist. It can be a complete osseous fusion or a partial connection that is cartilaginous or fibrous in nature.

The condition arises from abnormal embryologic segmentation of the distal carpal elements during development, leading to a persistent connection between the capitate and hamate. It may occur as an isolated anomaly or as part of broader carpal coalitions.

Most cases are asymptomatic and discovered incidentally on imaging performed for other reasons. When symptoms occur, they typically present as ulnar-sided wrist pain, especially with gripping or axial loading, sometimes with reduced range of motion or mechanical symptoms such as catching or a sense of sticking. Diagnosis is made with imaging: plain radiographs may reveal a continuous connection between the two bones, while computed tomography clarifies the type and extent of fusion and magnetic resonance imaging can assess cartilage and adjacent structures.

Management depends on clinical presentation. Asymptomatic individuals generally require no treatment. Symptomatic cases are first managed nonoperatively with activity modification, immobilization, and analgesia. If pain persists or degenerative changes develop, surgical options include excision or resection of the coalition to restore motion, or, in cases with instability, limited intercarpal fusion. The prognosis is variable: asymptomatic cases have a benign course, while symptomatic cases may respond differently to treatment depending on the extent of coalition and wrist mechanics.