Ph Neyret, E Servien, S Lustig, N Darwich (Lyon)
Even though valgus knee deformities often have a femoral origin, distal femoral osteotomy (DFO) is an uncommonly performed procedure. There is no true algorithm to direct its use, although there are some important factors that help in decision making. DFO changes the frontal plane alignment in extension only, and any valgus deformity in flexion will persist.
The ideal patient for DFO is thus a younger active patient with valgus deformity in or near extension, with isolated lateral compartment changes or with patellar femoral symptoms. Failure of non-operative treatment and motivation to undergo the long rehabilitation period are prerequisites. A study from Centre Albert Trillat reported on 29 patients undergoing lateral opening wedge osteotomy and autologous bone grafting using a AO blade plate, with average 80 months follow up. Eighty six per cent of patients were satisfied or very satisfied, and angular correction was good with average post-operative alignment 180.4 (±2.6). There was one loss of fixation and one non-union requiring revision fixation, and five revisions to arthroplasty at a mean of 166 months. Most of the patients required removal of the plate due to lateral soft tissue irritation, and these were carried out at a mean of 26 months.
Lateral opening wedge distal femoral osteotomy is easier to perform, and allows more accurate angular correction, than medial closing wedge osteotomy. With careful surgical technique, adjusted to account for the origin of the deformity and aiming to correct to 0-3° varus, good functional results are achievable. Delayed union is not common, but bone grafting and protected weight bearing are required, and removal of metal must be considered routine.