Dislocation of total hip replacement in patients with fractures of the femoral neck

BACKGROUND Total hip replacement is increasingly used in active, relatively healthy elderly patients with fractures of the femoral neck. Dislocation of the prosthesis is a severe complication, and there is still controversy regarding the optimal surgical approach and its influence on stability. We analyzed factors influencing the stability of the total hip replacement, paying special attention to the surgical approach. PATIENTS AND METHODS We included 713 consecutive hips in a series of 698 patients (573 females) who had undergone a primary total hip replacement (n = 311) for a non-pathological, displaced femoral neck fracture (Garden III or IV) or a secondary total hip replacement (n = 402) due to a fracture-healing complication after a femoral neck fracture. We used Cox regression to evaluate factors associated with prosthetic dislocation after the operation. Age, sex, indication for surgery, the surgeon's experience, femoral head size, and surgical approach were tested as independent factors in the model. RESULTS The overall dislocation rate was 6%. The anterolateral surgical approach was associated with a lower risk of dislocation than the posterolateral approach with or without posterior repair (2%, 12%, and 14%, respectively (p < 0.001)). The posterolateral approach was the only factor associated with a significantly increased risk of dislocation, with a hazards ratio (HR) of 6 (2-14) for the posterolateral approach with posterior repair and of 6 (2-16) without posterior repair. INTERPRETATION In order to minimize the risk of dislocation, we recommend the use of the anterolateral approach for total hip replacement in patients with femoral neck fractures.