Spontaneous union of a congenital pseudarthrosis of the tibia after Syme amputation.

A 4-year-old boy with congenital pseudarthrosis of the tibia had two unsuccessful operative attempts for union. After these procedures the patient had a 6-cm leg length discrepancy and an equinovalgus foot deformity. Because of these deformities he underwent Syme amputation at the ankle and was fitted with a total contact prosthesis. Eight months after the amputation, a solid union was seen across the pseudarthrosis site, although no attempt was made to achieve union with internal fixation or bone grafting. The authors think that vertical alignment of the limb in a total contact prosthesis, along with the compressive forces of weightbearing, allowed the pseudarthrosis site to heal in the patient.