UK research has shown that hormone replacement therapy (HRT) use is associated with an almost 40% reduction in revision rates after a total knee arthroplasty or total hip arthroplasty.
Osteolysis and subsequent prosthesis loosening is the most common cause for revision following total knee arthroplasty or total hip arthroplasty. HRT could reduce osteolysis through its antiresorptive effects.
The researchers used a large, community population-based retrospective cohort of women aged at least 40 years at the time of primary surgery for total knee arthroplasty or total hip arthroplasty. Those women with a medical diagnosis code for rheumatoid arthritis were excluded. Also excluded were women with a history of hip fracture prior to primary hip arthroplasty as the researchers could not accurately ascertain whether participants were undergoing total hip arthroplasty for osteoarthritis or for the hip fracture or its late complications.
Female participants in the General Practice Research Database undergoing a primary total knee arthroplasty or total hip arthroplasty from 1986 to 2006 were included. Women with at least 6 months of HRT were identified as HRT users.
The researchers further explored the associations among HRT use of ≥12 months, adherence (medication possession ratio) and cumulative use and revision risk. Cox models were fitted to model implant survival in years. Propensity score matching was used to control for confounding.
The study matched 2700 HRT users to 8100 non-users, observed for a median (IQR) of 3.3 (1.5-6.1) years after total knee arthroplasty or total hip arthroplasty.
HR for HRT ≥6 months was 0.62 (95% CI 0.41 to 0.94), whereas HR for ≥12 months was 0.48 (0.29 to 0.78).
Higher adherence and therapy duration were associated with further reductions in revision rates.
Preoperative HRT appeared unrelated to implant survival.
The researchers noted in their conclusion that the findings require replication in external cohorts and experimental studies.
D. Prieto-Alhambra, M. K. Javaid, A. Judge, J. Maskell, C. Cooper, N. K. Arden, M. Mullee, J. Rafferty, A. Carr, A. Price, K. Javaid, D. Beard, D. Altman, N. Clarke. Hormone replacement therapy and mid-term implant survival following knee or hip arthroplasty for osteoarthritis: a population-based cohort study. Annals of the Rheumatic Diseases, 2014; DOI: 10.1136/annrheumdis-2013-20404
Content updated 15 July 2014