Distal Femoral Valgus Deformity Following Plate Fixation of Pediatric Femoral Shaft Fractures

Abstract

This study investigated the frequency and potential risk factors associated with the development of distal femoral valgus deformity following plate fixation of diaphyseal femoral fractures in children. Records of eighty-five skeletally immature patients who underwent plate fixation of a diaphyseal femoral fracture at a tertiary-care pediatric center from January 2003 to December 2010 were reviewed. Demographic data and clinical information were analyzed. Radiographic measurement of the distance from the distal plate edge to the distal femoral physis and of the anatomic lateral distal femoral angle was performed. Development of distal femoral valgus deformity was defined as a change in the anatomic lateral distal femoral angle of ≥5° in the valgus direction. Logistic regression analysis and contingency tables were used to relate the development of distal femoral valgus deformity with retention of hardware, patient age, fracture site, plate-to-physis distance, and the location of a bend in the plate at fixation. Midshaft fractures (45%) were more common than proximal or distal diaphyseal fractures. Intraoperatively, the plate was bent proximally or distally, or both, in 80% of the patients. Distal femoral valgus deformity of ≥5° was seen in ten patients, eight of whom had distal diaphyseal fractures. Three of the ten patients developed symptoms as a result of the distal femoral valgus deformity that required at least one unplanned additional surgical procedure. On the basis of the statistical analysis, patients with a plate-to-physis distance of ≤20 mm (relative risk= 12.77, p = 0.005) and a distal fracture (relative risk = 11.0, p < 0.001) were at a significantly higher risk of developing distal femoral valgus deformity. Although not clearly an independent factor, a distal bend was also found to be associated with distal femoral valgus deformity (p = 0.004) but was not predictive of the pathology. Distal femoral valgus deformity occurred in 30% of patients with distal diaphyseal fractures and in 12% overall. We advocate long-term monitoring of patients with femoral plate fixation, particularly those in whom the plate is placed ≤20 mm from the distal femoral physis.