Lenguerrand E, et al. - Researchers determined the overall and time-specific associations of the patient, surgical, and health-care factors with the risk of revision due to prosthetic joint infection (PJI) after primary total hip replacement. At the patient level, men, younger patients, and those with high body-mass index or high American Society of Anaesthesiologists (ASA) grades were identified to be an higher risk of revision for PJI. The risk of revision for PJI was increased in presence of comorbidities such as chronic pulmonary disease, diabetes, dementia, liver disease, congestive heart failure, and connective tissue or rheumatic diseases. At the surgical level, patients undergoing THR for fractured neck of femur or avascular necrosis were identified to be at higher risk of revision for PJI. The health-care system-level factors were less important with no marked sustained associations. The incidence of PJI could be effectively reduced via identification of modifiable factors, use of targeted interventions, and beneficial modulation of some of these factors.

Methods

• Analysis of 623,253 primary hip procedures performed between April 1, 2003, and Dec 31, 2013, in England and Wales was performed in this prospective observational cohort study.
• Documentation was performed of the number of procedures revised because of PJI.
• Using Poisson multilevel models, the associations between risk factors and risk of revision for PJI were investigated across the overall follow-up period.
• Using piece-wise exponential multilevel models with period-specific effects, researchers reinvestigated the associations by post-operative time periods (0–3 months, 3–6 months, 6–12 months, 12–24 months, >24 months).
• The National Joint Registry linked to the Hospital Episode Statistics data was used for obtaining data.

Results

• Researchers subsequently revised 2705 primary procedures for an indication of PJI between 2003 and 2014, after a median (IQR) follow up of 4·6 years (2·6–7·0).
• Factors associated with an increased revision due to PJI included male sex (1462 [1·2‰] of 1 237 170 male-years vs 1243 [0·7‰] of 1 849 691 female-years; rate ratio [RR] 1·7 [95% CI 1·6–1·8]), younger age (739 [1·1‰] of 688 000 person-years <60 years vs 242 [0·6‰] of 387 049 person-years ≥80 years; 0·7 [0·6–0·8]), elevated body-mass index (BMI; 941 [1·8‰] 517 278 person-years with a BMI ≥30 kg/m² vs 272 [0·9‰] of 297 686 person-years with a BMI <25 kg/m²; 1·9 [1·7–2·2]), diabetes (245 [1·4‰] 178 381 person-years with diabetes vs 2120 [1·0‰] of 2 209 507 person-years without diabetes; 1·4 [1·2–1·5]), dementia (5 [10·1‰] of 497 person-years with dementia at 3 months vs 311 [2·6‰] of 120 850 person-years without dementia; 3·8 [1·2–7·8]), previous septic arthritis (22 [7·2‰] of 3055 person-years with previous infection vs 2683 [0·9‰] of 3 083 806 person-years without previous infection; 6·7 [4·2–9·8]), fractured neck of femur (66 [1·5‰] of 43 378 person-years operated for a fractured neck of femur vs2639 [0·9‰] of 3 043 483 person-years without a fractured neck of femur; 1·8 [1·4–2·3]); and use of the lateral surgical approach (1334 [1·0‰] of 1 399 287 person-years for lateral vs 1242 [0·8 ‰] of 1 565 913 person-years for posterior; 1·3 [1·2–1·4]).
• A decreased risk of revision for PJI was noted in association with the use of ceramic rather than metal bearings (94 [0·4‰] of 239 512 person-years with ceramic-on-ceramic bearings vs 602 [0·5‰] of 1 114 239 peron-years with metal-on-polyethylene bearings at ≥24 months; RR 0·6 [0·4–0·7]; and 82 [0·4‰] of 190 884 person-years with ceramic-on-polyethyene bearings vsmetal-on-polyethylene bearings at ≥24 months; 0·7 [0·5–0·9]).
• Time-specific effects of most of these factors were observed.
• The grade of the operating surgeon, the absence of a consultant surgeon during surgey, and the volume of procedures performed by hospital or surgeon marginally or did not influence the risk of revision for PJI.