Scaphoid nonunion and flexor pollicis longus tendon rupture.

Four patients presented with a rupture of the flexor pollicis longus tendon that was associated with a longstanding scaphoid nonunion. A radiocarpal arthrosis was present in 3 of the 4 patients and a dorsiflexed intercalated segment instability deformity was also seen in 3 of the 4 patients. Three patients underwent surgery consisting of an osteosynthesis with an iliac bone graft for the scaphoid nonunion and a palmaris longus tendon graft for the ruptured flexor pollicis longus tendon. An osseous union of the scaphoid and a functional active range of motion of the thumb interphalangeal joint (33 degrees on average) was attained in all 3 of the patients treated surgically. Preoperative radiologic examinations and intraoperative findings suggest that the volarly protruding distal scaphoid segment is the cause of the rupture.