Bone realignment with use of temporary external fixation for distal femoral valgus and varus deformities.

BACKGROUND Correction of a distal femoral deformity may prevent or delay the onset of osteoarthritis or mitigate its effects. Accurate correction of deformity without production of a secondary deformity depends on precise localization and quantification of the deformity. We report a technique to correct distal femoral deformities in the coronal plane. METHODS Fourteen femora in thirteen skeletally mature patients with a distal femoral deformity underwent operative reconstruction. The preoperative deviation of the mechanical axis ranged from 90 mm laterally (genu valgus) to 120 mm medially (genu varus). The mechanical lateral distal femoral angle was abnormal in all fourteen knees. The technique consisted of application of an external fixator, performance of a percutaneous distal femoral dome osteotomy, correction of the deformity, and locking of the external fixator. A statically locked retrograde intramedullary nail was inserted following reaming, and the external fixator was removed. The mean duration of follow-up was thirty-three months (range, six to forty-seven months). RESULTS The mean time until healing was thirteen weeks (range, six to thirty-nine weeks). Nine of the thirteen patients reported an improvement in walking, and none needed an assistive device. All nine patients with preoperative knee pain were free of tibiofemoral pain at the most recent follow-up evaluation. The mechanical lateral distal femoral angle was within the normal range in twelve of the fourteen knees. The mechanical axis was within the normal range in ten lower extremities. In three of the four remaining limbs, the residual abnormal deviation of the mechanical axis was due to a residual tibial deformity. CONCLUSIONS Percutaneous dome osteotomy combined with temporary external fixation and insertion of an intramedullary nail can correct distal valgus and varus femoral deformities. We attributed the early mobilization of patients and the rapid bone-healing to the limited soft-tissue dissection, the low-energy corticotomy, and the use of intramedullary fixation in our surgical technique.