Reduced risk of reoperation after treatment of femoral neck fractures with total hip arthroplasty

Background and purpose - Femoral neck fractures (FNFs) are commonly treated with some kind of arthroplasty, but evidence on whether to use hemiarthroplasty (HA) or total hip arthroplasty (THA) is lacking. HA reduces the risk of dislocation, but may lead to acetabular erosion. THA implies longer surgery and increased bleeding. THA may result in better function and health-related quality of life, but evidence is contradictory. We compared HA and THA and in terms of revision, reoperation and death. Patients and methods - Data were extracted from the Swedish Hip Arthroplasty Register for 11,253 patients with acute FNF receiving cemented HA or THA during 2008-2012. 2,902 patients with THA were matched by propensity score matching with as many patients with HA based on age, sex, BMI, and ASA classification. We used competing risks survival regression with reoperation or death and revision or death as endpoints. Results - THA patients had significantly reduced risk of revision (absolute risk reduction 0.51; 95% CI 0.39-0.67) and reoperation (0.58; 0.46-0.74). THA was associated with an almost 50% reduced mortality (risk ratio as competing risk for reoperation 0.51; 0.46-0.57). Interpretation - In our national register study of femoral neck fractures, THA had a lower risk than HA for further surgical procedures related to the hip. The reasons for lower mortality after THA are not known. Despite matching, there might be a selection of more healthy patients for this procedure, and other factors unknown to us, with or without relation to the choice of implant.