Intra-articular hip injection and early revision following total hip arthroplasty: a retrospective cohort study
Ravi B, Escott B, Wasserstein D, Croxford R, Hollands S, Paterson JM, Kreder H, Hawker GA. Arthritis Rheumatol. 2015; 67(1):162-8. Epub 2014 Sep 23.
Objective — Therapeutic intra-articular injections are used in the management of hip osteoarthritis (OA). Some studies suggest their use increases risk for infection, and thus revision, after THA, while others do not. The authors sought to clarify the relationship between prior intra-articular injection and the risk of complication in a subsequent total hip arthroplasty (THA).
Methods — In a cohort with hip OA who received a primary elective THA between 2002 and 2009, the authors identified those who received ≥1 intra-articular injection by a radiologist in the five years preceding their THA. Multivariable Cox proportional hazards models were used to determine the relationship between receipt of a pre-surgical injection (none, 1-5 years prior, or < 1year prior) and the occurrence of post-surgical joint infection and revision THA in the following 2 years, while controlling for confounders.
Results — Of 37,881 eligible THA recipients, 2,468 (6.5%) received an intra-articular injection from a radiologist within five years of their THA (<1y: 1,691; 1-5years: 777). Controlling for age, sex, co-morbidity, frailty, income, and provider volume, those who had an injection in the year preceding surgery were at increased risk for infection (adjusted HR 1.37, p=0.03) and revision (adjusted HR 1.53, p=0.03) within 2 years of the THA, relative to patients that did not. The association between prior injection and revision arthroplasty was attenuated and became non-significant (adjusted HR 1.41, p=0.13) after occurrence of post-operative infection was included in the regression model. No effect was found for injection 1-5 years prior to surgery.
Conclusions — Intra-articular injection in the year preceding THA independently predicted increased risk for infection leading to early revision. Further studies are warranted to elucidate explanations for these findings