Congenital metacarpal synostosis treated by longitudinal osteotomy and placement of a silicone wedge.

Three cases of congenital metacarpal synostosis are reported. Two had congenital synostosis between the fourth and fifth metacarpal, and one between the third and fourth metacarpal. Both hands were involved in the former cases, while only one unilateral hand was involved in the latter case. An abnormal abduction position of the finger was noted in early infancy, and this gradually progressed as the patients grew. Operations were performed between the ages of three to eleven years. Fused metacarpal bases were longitudinally osteotomized with a chisel, and a silicone wedge was inserted between the metacarpal bases. After the operation, the hand was immobilized with a plaster cast for four weeks. The follow-up periods range from two to sixteen years. The postoperative function and appearance of the hand were remarkably improved.