HRT may lower risk of repeat knee/hip replacement

Taking hormone replacement therapy (HRT) for at least 6 months after total knee arthroplasty (TKA) or total hip arthroplasty (THA) may reduce risk of repeat surgery. So say the results of a community-based cohort study of women in the UK who had undergone TKA or THA for osteoarthritis.

Published in Annals of the Rheumatic Diseases, the population-based study looked at outcomes in 10,800 women aged ≥40 who had undergone TKA or THA between 1986 and 2006. None of the participants had a history of previous hip fracture or rheumatoid arthritis; 2,700 had taken HRT for ≥6 months whereas 8,100 had not.

At median observation of 3.3 years after TKA/THA, researchers from the University of Oxford reported a hazard ratio (HR) for need for repeat surgery of 0.62 (95% CI 0.41 to 0.94) in those who had taken HRT for ≥6 months versus 0.48 (0.29 to 0.78) in those who had taken it for ≥12 months. Rates of revision were even lower the longer a woman took HRT and the better she adhered to it. Taking HRT before surgery, however, did not influence implant survival.

The findings, which the authors say show a link between HRT use and an almost 40% reduction in revision rates after TKA/THA, require replication in external cohorts and experimental studies. 

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