distraction rate, the less the healing index and consolidation time. Conclusion. Age has the most effect on healing index and consolidation time. Metacarpal lengthening using callus distraction is recommended. Adolescence is the most appropriate time to perform distraction lengthening of a congenitally short metacarpal. This will avoid additional lengthening of normal metacarpals prior to epiphyseal closure.

A large kindred which was first described in 1995 was investigated again. We present the clinical, radiological, genetic and surgical findings of the hand deformities found in homozygote individuals which we called "hypoplastic synpolydactyly". There were 125 affected (heterozygote or homozygote) people out of 245 subjects in the five last generations. We identified seven marriages of two affected people. Twelve offsprings, of these marriages had a homozygote genetic pattern and "hypoplastic synpolydactyly". From both the clinical and surgical perspectives, their hand deformity was distinctive from that of their parents. We surgically treated both hands of three individuals with this deformity. The hand deformity of these homozygotes was so complicated and distinctive that it can be evaluated as a new subgroup of synpolydactyly.

The existence and variety of unusual bones may indicate the severity of penetrance and expressivity of SPD.