[Thumb duplication: an analysis of 72 thumbs].

Objectives: The aim of this study was to evaluate patients who were operated on for a duplicated thumb.

Methods: Sixty-seven patients (41 females, 26 males; mean age 2.5 years; range 6 months to 20 years) underwent surgery for a total of 72 duplicated thumbs between 1982 and 2003. Five patients had bilateral involvement. The anomaly was on the right in 39 cases, and on the left in 33 cases. Clinical and radiographic evaluations were made according to the Wassel classification. The Bilhaut-Cloquet technique was used in 13 symmetrically duplicated thumbs, while simple excision of the unserviceable part was performed in the remaining. Patient satisfaction was assessed with the use of a visual analog scale after a mean follow-up period of 3.6 years (range 1 to 10 years).

Results: Nail deformity was present in all cases treated by the Bilhaut-Cloquet technique. These thumbs did not exhibit growth retardation, but interphalangeal joint motion was limited in five, while seven had a larger size compared to the normal side. Limited range of motion was detected in eight cases (11.9%), affecting the metacarpophalangeal joint in one, and the interphalangeal joint in the others. Seventeen patients (25.4%) developed an angulation of more than 10 degrees in the alignment of the thumb. Secondary procedures were necessary in 25 cases (37.3%), including collateral ligament reconstruction (n=12; 17.9%), tendon rerouting (n=3; 4.5%), corrective osteotomy (n=5; 7.5%), and arthrodesis of the interphalangeal joint (n=5; 7.5%). Patient satisfaction with the surgical outcome was 85% (n=57).

Conclusion: It is important to evaluate and treat the skin, nail, bone, and the ligaments in a simultaneous manner in order to obtain a good reconstruction and to decrease both the complications and the need for subsequent operations.