The "Bilhaut-Cloquet" technique for treatment of thumb duplication.

The presentation of thumb duplication is variable depending on the level of bifurcation, the relative sizes of the two thumbs and their possible symmetry along a longitudinal axis. Resection of the supernumerary thumb often leads to disappointing results when both thumbs are hypoplastic. The principle of the "Bilhaut-Cloquet" procedure involves central resection of the duplication followed by fusion of the remaining lateral portions, in order to obtain a thumb of satisfactory volume. Thirteen children with unilateral thumb duplication were treated using the "Bilhaut-Cloquet" procedure. Nine cases involved duplication of the distal phalanx (Wassel type II). Five of these duplications were symmetrical and four were asymmetrical with an associated proximal delta phalanx. In these cases, a corrective osteotomy of the delta phalanx was performed at the same time. Four cases involved symmetrical duplications of both proximal and distal phalanges (Wassel type IV). The mean age at time of surgery was 11.5 months. Patients were reviewed with a mean follow-up of four years. The aesthetic aspect of the nail was judged as good in 12 cases. In one case, the aesthetic aspect of the nail was judged as fair due to a prominent longitudinal ridge. Bony fusion was obtained in all cases but one. The alignment was corrected in all cases but four, involving asymmetrical duplications. Joint mobility was limited in all patients. The "Bilhaut-Cloquet" technique leads to a satisfactory volume of the thumb in selected cases. Good correction of preoperative angular deformity is obtained in symmetrical cases. A precise technique of bone and nail approximation yields good functional and aesthetic results. The "Bilhaut-Cloquet" technique is indicated in balanced and symmetrical duplications, when the two thumbs are severely hypoplastic. It can be used either in the distal or proximal phalangeal types of thumb duplication.