Male sex, younger age, and higher body mass index were three of several factors associated with increased risk for revision of hip replacement surgery due to prosthetic joint infection, researchers found.
A prospective observational study looked at primary hip replacements done between April 1, 2003, and Dec. 31, 2013, in England and Wales to determine how many needed to be revised due to prosthetic joint infection. Associations between risk factors and risk for surgery revision were examined according to postoperative time period, and all patients were followed for at least 12 months, until the end of the observation period, revision due to infection or another reason, or death. The study results were published July 25 by The Lancet Infectious Diseases.
Of the 623,253 procedures studied, 2,705 were revised due to prosthetic joint infection after a median follow-up of four to six years. Fourteen percent of revisions were done within three months of the initial procedures, 8% were done within three to six months, 14% were done within six to 12 months, 23% were done within 12 to 24 months, and 42% were done after more than 24 months. The mean age of patients in the study was 68 years.
Factors associated with increased risk for revision due to infection were male sex (rate ratio [RR], 1.7; 95% CI, 1.6 to 1.8), younger age (RR, 0.7 [95% CI, 0.6 to 0.8] for <60 years vs. ≥80 years), higher body mass index (RR, 1.9 [95% CI, 1.7 to 2.2] for ≥30 kg/m2 vs. <25 kg/m2), diabetes (RR, 1.4; 95% CI, 1.2 to 1.5), dementia (RR, 3.8; 95% CI, 1.2 to 7.8), previous septic arthritis (RR, 6.7; 95% CI, 4.2 to 9.8), fractured neck of femur (RR, 1.8; 95% CI, 1.4 to 2.3), and use of the lateral versus posterior approach for surgery (RR, 1.3; 95% CI, 1.2 to 1.4). Patients in whom ceramic bearings were used instead of metal bearings were at lower risk for revision due to infection (RR at ≥24 months, 0.7; 95% CI, 0.5 to 0.9). Time-specific effects were seen for most risk factors.
The researchers noted that their study was observational and that they had no data available on the cause of the reported infections, among other limitations. They pointed out that current preventive strategies for prosthetic joint infection focus mainly on hygiene, use of protective equipment, systemic antibiotics, and other similar measures and could be enhanced by the use of patient-related factors such as those identified in their study.
“For patients about to have hip replacement, identification of modifiable factors, use of targeted interventions, and beneficial modulation of some of these factors could be effective in reducing the incidence of [prosthetic joint infection],” the authors wrote. “It is important for clinicians to consider the non-modifiable factors, and the factors that exhibit time-specific effects on the risk of [prosthetic joint infection], to counsel patients appropriately preoperatively.”