Locking of the metacarpophalangeal joint of the thumb caused by a fracture fragment of the radial condyle of the metacarpal head after dorsal dislocation.

We report a case of a locked thumb metacarpophalangeal joint secondary to metacarpal head fracture. As fractures of the radial condyle are not readily seen in routine X-rays, other imaging modalities, including CT, should be considered if the patient complains of limited extension after hyperextension injury of the thumb.