Displaced intracapsular neck of femur fractures: dislocation rate after total hip arthroplasty

Includes bibliographical references ; Background: Dislocation is one of the most common orthopaedic complications after primary total hip arthroplasty (THA). The reported dislocation rate in elective THR is 5 - 8%. This number increases up to 22% for THA done for neck of femur fractures. Larger femoral head sizes increase the head-neck ratio and range of motion before impingement, therefore reducing the dislocation rate. Due to the reported increase in dislocation for trauma, some surgeons prefer to do a hemi-arthroplasty or open reduction and internal fixation (ORIF). Methods: A retrospective review of all THA done for neck of femur fractures during 2006 - 2012 was undertaken at a large referral hospital. Records were reviewed for patient related and surgical risk factors. We excluded all pathological fractures, extra-capsular fractures and failed ORIF. Results: A total of 96 cases were identified as suitable for analysis. Average age at surgery was 73.2 years (range 30 - 81). Delay to surgery was 5.3 days (range 1 - 63). Average follow up period was 18.3 months (range 3 months - 4.3years). Four patients (4.3%) had a confirmed dislocation. The four patients who had confirmed dislocation had the following characteristics, 28 mm femoral head size, age over 60 years, 2 posterior approaches and 3 females, although not statistically significant. Conclusion: The outcomes of THR in patients with neck of femur fractures can be favourable and provide good long-term prosthesis survival. We report on low dislocation rate post total hip replacement for intra-capsular neck of femur fractures.