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

Abstract

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 (NOF) 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 hemiarthroplasty or open reduction and internal fixation (ORIF) rather than a THA. METHODS: A retrospective review of all THAs done for NOF fractures during 2006 to 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 92 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 to 4.3 years). 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, two posterior approaches and three females, although not statistically significant. CONCLUSION: The outcomes of THA in patients with NOF fractures can be favourable and provide good long-term prosthesis survival. We report on low dislocation rate post total hip replacement for intra-capsular NOF fractures. Level of evidence: Level 4.