Radiocarpal osteoarthritis associated with bilateral bipartite carpal scaphoid bones: a case report.

Bipartite carpal scaphoid is a rare congenital anomaly. The authors report on a 56-year-old man who presented with bilateral wrist pain without a history of trauma. X-ray films demonstrated bilateral symmetric bipartition of the scaphoid into a large distal ossicle and a smaller proximal ossicle. There was degenerative change in the articulation between the distal ossicle and the radial styloid. The joint space between the proximal ossicle and the scaphoid fossa was preserved. The absence of periscaphoid degenerative change has been suggested as a criterion for the diagnosis of congenital bipartite scaphoid. This patient fulfilled all other criteria for the diagnosis and the authors suggest that degenerative change developed due to abnormally high contact force between the distal ossicle and the radial styloid. An identical pattern of degenerative change has been observed in long-standing nonunion of the scaphoid, likely due to a similar mechanism. Radiocarpal osteoarthritis can develop in patients with congenital bipartition of the scaphoid and is similar to that observed in long-standing nonunion of the scaphoid.