[Surgical treatment of duplication of the thumb. Apropos of 106 cases].

The surgical treatment of thumb duplication remains difficult, the sequelae usually observed are aesthetic (ungual dystrophy, hypoplastic pulp, clinodactyly) or functional (joint stiffness or instability). In order to clarify our therapeutic approach, we classify duplications into two types: proximal duplications (Wassel stage IV, V and VI) and distal duplications (Wassel stage I, II and III). Our experience is based on 106 cases operated over the last 15 years (1977). Our indications and operative techniques have progressed since 1988, in particular, we no longer perform Bilhaut-Cloquet operation, and prefer to perform the first operation before the age of one year. Resection of the hypoplastic supernumerary thumb. Preservation of the pulp skin to reconstitute the paronychium and pulp of the remaining thumb. Resection of supplementary joint facets. Meticulous repair of the capsulo-ligamentus apparatus by means of a capsulo-periosteal flap taken from the "sacrificed" thumb. Tendinous reequilibration and reinsertion of thenar muscles. We do not perform systematic subcapital osteotomy. When necessary, this procedure is performed during a complementary operation at the age of 2 to 3 years. Since the introduction of these technical modifications, our functional and aesthetic results have improved. Temporary overcorrection of the pulp is necessary. Parents must be advised that this deliberately hypertrophic appearance becomes normal with growth.