Management of thumb duplication.

Radial polydactyly, a common congenital problem, most often occurs as thumb duplication. It appears in pentadactylous, polydactylous, and hypoplastic hands and is simulated by complex syndactyly. Classically, there are three categories for radial polydactyly: severe hypoplasia, partial duplication, and total duplication (easily confused with pseudoduplication). The common second category is subcategorized by Wassel's seven types. Management techniques vary with these classifications. Until a decade ago, the standard recommendation was simple excision of one of the duplicates. Problems of deformity, instability, and weakness became apparent, and reconstructive options were developed. Review of a series of 54 duplicate thumbs, all surgically treated, reflects the changing pattern of reconstruction. With current techniques, good results are usual, although secondary reconstructive procedures may be required. Simple excision is seldom indicated. Combination procedures, involving core tissues of bone, joint, and tendon or peripheral tissues--neurovascular, subcutaneous, and skin--or sometimes all of these, are preferred for reconstruction. The major current problem is to achieve the maximal good result with a minimal number of surgical operations.