Hormone replacement therapy and mid-term implant survival following knee or hip arthroplasty for osteoarthritis: a population-based cohort study.
OBJECTIVE
Osteolysis and subsequent prosthesis loosening is the most common cause for revision following total knee arthroplasty (TKA) or total hip arthroplasty (THA). Hormone replacement therapy (HRT) could reduce osteolysis through its antiresorptive effects. We studied whether HRT use is associated with reduced revision rates in a community-based cohort of women undergoing TKA or THA for osteoarthritis.


METHODS
Female participants in the General Practice Research Database undergoing a primary TKA or THA from 1986 to 2006 were included. We excluded patients aged <40 years at the date of primary, and those with a history of previous hip fracture or rheumatoid arthritis. Women with at least 6 months of HRT were identified as HRT users. We 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.


RESULTS
We matched 2700 HRT users to 8100 non-users, observed for a median (IQR) of 3.3 (1.5-6.1) years after TKA/THA. 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.


CONCLUSIONS
HRT use is associated with an almost 40% reduction in revision rates after a TKA/THA. These findings require replication in external cohorts and experimental studies.
Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK GREMPAL Research Group, IDIAP Jordi Gol Primary Care Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain URFOA, Institut Municipal d'Investigacions Mèdiques (IMIM), Parc de Salut Mar, Barcelona, Spain RETICEF (Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad), Instituto Carlos III, Madrid, Spain.
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Prieto-Alhambra
Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
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Javaid
Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
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Judge
MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
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Maskell
Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
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Cooper
Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
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Arden
D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D015331:Cohort Studies; D015914:Estrogen Replacement Therapy / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D055118:Medication Adherence; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D016016:Proportional Hazards Models; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies
Epidemiology; Knee Osteoarthritis; Orthopedic Surgery; Osteoarthritis