Thumb metacarpal lengthening.

Over a period of 35 years, 92 patients have been treated: 70 adults and 22 children age 8 to 14. The metacarpal lengthening obtained varied from 2 to 4.5 cm with an average of 3.5 cm, or equal to the length of a thumb proximal phalanx. In one third of the adult patients, due to delayed spontaneous ossification, the interfragmental space was bridged by a bone graft taken from the iliac crest. Late follow-up of 21 patients made 10 to 14 years after the treatment showed good function of the thumb with a normal pattern of skin sensibility. The lack of trophic changes in the distal part of the reconstructed thumb is due to the interposition type of bone lengthening, that is, the new bone structure is placed into the bone middle and not superimposed on the bone stump end, as is done in other methods of thumb reconstruction. The metacarpal lengthening procedure has the following drawbacks: (1) the full treatment course lasts several months; (2) the reconstructed thumb has neither joint nor nail. Advantages of the method are: (1) reconstruction of the thumb is done by using the available stump tissue resources; (2) the reconstructed thumb is covered by its own, normally innervated skin.