Introduction: Surgical site infection following total hip replacement results in poorer outcomes, longer hospital stays, and increased costs. The aim of this study was to describe infective complications in a large series of total hip arthroplasty.

Methods: Between January 1998 and March 2005, consecutive total hip arthroplasties were prospectively. The presence of deep infection was confirmed by culture from joint aspiration or a secondary procedure such as joint washout or component removal and replacement. Risk factors for development of surgical site infective complications were analysed.

Results: 2029 consecutive total hip arthroplasties was carried out in 1539 patients. There were 22 deep infections (1.1%) and 118 superficial infections (5.8%). Staphylococcus aureus (MSSA) was isolated in 10/22 (45%) of deep infections and MRSA in 4 (18%). In patients undergoing unilateral replacement there were 11/1539 deep infections (0.7%) compared 5/172 (2.9%) in the bilateral simultaneous group. In patients who were current or exsmokers the deep infection rate was 11/880 (1.3%) compared to 7/864 (0.8%) in non-smokers. 3/120 (2.5%) diabetic patients developed deep infection. In patients who received a blood transfusion 9/502 (1.7%) developed deep infection compared to 13/1527 (1%) who did not. In patients with a BMI> 35kgm⁻² the overall rate of infective complications (superficial and deep) was 18.8%. In patients with a report of a perioperative complication the deep infection rate was 6/169 (3.6%) compared to 16/1860 (0.9%) without complication.

Discussion: This study has the advantage of investigating infective complications in a typical case series of patient presenting for total hip replacement. The rate of deep infection was consistent with previous reports. Deep infection is associated with bilateral simultaneous replacement, smoking, diabetes, blood transfusion and perioperative complications. Obese patients are at higher risk of all surgical site infective complications.