Varus malunion as an outcome of pertrochanteric fracture fixation

Background: Despite the high incidence of pertrochanteric fractures in African countries, there are insufficient data on radiographic outcomes of fixation. Previous studies focused on cut-out as an outcome measure. Varus malunion may be a significant outcome measure as it results in biomechanical alterations at the hip. Objective: This study aimed to identify varus malunion as an outcome of pertrochanteric fracture fixation in our population. Study design: This was a cross-sectional, prospective, observational study. Patients and methods: Fifty-nine patients were operated on at three facilities over a 1-year period. Post-operative neck–shaft angle (NSA) and tip–apex distance (TAD) were measured. After 12 weeks, radiographs were assessed for varus malunion and cut-out. Results: The mean post-operative NSA was 3° of varus and the mean TAD was 36 mm. After 12 weeks, there was an average varus collapse of 6°. Predictors of varus collapse were increased TAD (p = 0.002) and decreased post-operative NSA (p < 0.001). The cut-out rate was 4.9%. Conclusion: Pertrochanteric fractures show varus collapse after fixation. Reduction in valgus may allow the fracture to collapse into a near-anatomical position, avoiding malunion. The position of the implant within the femoral head plays an active role in preventing varus malunion.