Hypoplastic thumbs Type II of the Blauth classification can be treated successfully by:
A. Releasing the contracted first web space, reconstruction of the ulnar collateral ligament, transposition flap to release the first web space, a full thickness skin graft and opponensplastyReleasing the contracted first web space, reconstruction of the ulnar collateral ligament, transposition flap to release the first web space, a full thickness skin graft and opponensplasty. In hypoplasia of the thumb, Blauth Type 2, the thumb is smaller and less stable than normal. The hypoplasia has three elements: 1) adduction contracture of the first web space is apparent because of 2) the lack of thenar muscles, and the hand compensates by exhibiting 3) laxity of the ulnar collateral ligament that allows abduction of the MCP joint. The skeleton, although small, has normal articulations. Treatment of this condition requires: a) release of the first web space using a dorsal flap from the thumb - preferably, as described by Strauch, and closing the thumb defect with a full thickness skin graft; b) reconstruction of the ulnar collateral ligament, as described by Lister using the division of the flexor digitorum superficialis (FDS) that is utilized for c) an opponensplasty, as described by Royle. There are other methods for soft tissue release, ligament reconstruction and opponensplasty, but this is the simplest and probably the least invasive while reducing morbidity of donor sites.
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