Valgus ankle secondary to acquired fibular pseudoarthrosis in children. Long-term results of the Langenskiöld operation.

Nine cases of acquired absence of the fibular shaft were studied to determine the growth contribution of the distal fibula; in 6 cases the absence was caused by osteomyelitis and in 3 cases by trauma. The average valgus and external rotational deformities were 15.2 degrees and 10 degrees, respectively. In 3 of 7 cases surgically treated with Langenskiöld operation or supramalleolar corrective osteotomy, the valgus deformity recurred during the postoperative growth period. The speculated causes of gradual valgus deformity are the loss of physiologic thrust from the proximal to distal fibula, the tethering effect of contracted soft tissue on distal fibula and early physeal closure of the lateral part of the distal tibia due to continuous, uneven axial overloading. The Langenskiöld operation was found effective for the stability of ankle joint in the initial period, but could not prevent the postoperative revascularization of the ankle. However, it is strongly recommended that any types of prophylactic surgery should be carried out before the development of an epiphyseal deformity of distal tibia, and to prevent secondary osteoarthritis of the ankle joint.