National guidelines encourage the use of total hip arthroplasty (THA) to treat intracapsular neck of femur fractures. There have been no population based studies appraising the surgical outcomes for this indication across an entire population. This study aims to calculate the complication rates for THA when performed for a fractured neck of femur and compare them to THA performed for primary osteoarthritis in the same population.

The Scottish Arthroplasty Project identified all THAs performed in Scotland for neck of femur fracture and osteoarthritis between 1st of January 2009 and 31st December 2014. Dislocation, periprosthetic infection and revision rates at 1 year were calculated.

The rate of dislocation, periprosthetic infection and revision at 1 year were all significantly increased among the fracture neck of femur cohort. In total 44046 THAs were performed, 38316 for OA and 2715 for a neck of femur fracture. 2.1% of patients (n=57) who underwent a THA for a neck of femur fracture suffered a dislocation in the 1st year postoperatively, compared to 0.9% (n=337) when the THA was performed for osteoarthritis. Relative Risk of dislocation: 2.4 (95% C.I. 1.8077–3.1252, p value <0.0001). Relative Risk of infection: 1.5 (95% C.I. 1.0496–2.0200, p value 0.0245) Relative Risk of revision: 1.5 (95% C.I. 1.0308–2.1268, p value 0.0336).

This is the first time a dislocation rate for THA performed for a neck of femur fracture has been calculated for an entire population. As the number of THAs for neck of femur fracture increases this dislocation rate will have clinical implications.