Teaching Case

Painful wrist after a fall. We highlight this rare case of carpal coalition with an associated carpal bone fracture.

The patient complained of a painful wrist after falling onto his hand 4 days ago. Plain radiographs showed an old scaphoid fracture and trapezo-capitate coalition as an incidental finding. He had several injuries to his hand playing cricket in the past that might have accounted for his scaphoid fracture.

Coalition between carpal bones are more common than coalition in carpal-metacarpal bones or forearm bones. The most common fusion is that between the lunate and triquetrum , with capitate-hamate fusion being the second most common. Carpal fusions are usually seen in conjunction with other skeletal anomalies, such as brachydactyly, camptodactyly, ulnar club hand, duplication of phalanx and pseudoepiphysis of metacarpal. Fusion between the two rows are extremely rare and there has been a case report of complete entire carpal coalition and carpometacarpal coalition occurring bilaterally . The incidence of carpal coalition in the white population is about 0.2 percent and in the black population is about ten times as common. The maximum incidence of about 9.5 pecent being reported from West Africa. Though this condition is considered to be asymptomatic; incomplete fusion has been reported to demonstrate osteoarthritic changes and pseudoarthrosis which can lead to wrist pain.