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