Hormone Replacement Therapy Reduces Risk of Revision Surgery After Ortho Implant

A new study in the Annals of Rheumatic Disease suggests that hormone replacement therapy (HRT) taken regularly for six months can cause a significant reduction in the risk of repeat surgery after a hip or knee replacement.

According to the study authors, osteolysis and subsequent prosthesis loosening is the most common cause for revision following total knee arthroplasty (TKA) or total hip arthroplasty (THA). Osteolysis occurs when particles from the implant leak into the surrounding tissue, causing inflammation and subsequently destroying the bone around the implant. HRT could, the study posited, reduce osteolysis through its antiresorptive effects. The researchers studied whether HRT use is associated with reduced revision rates in a community-based cohort of women undergoing TKA or THA for osteoarthritis.

The study included female participants in the General Practice Research Database undergoing a primary TKA or THA from 1986 to 2006. This database contains anonymous records of patients from across the United Kingdom. Patients aged less than 40 years and those with a history of previous hip fracture or rheumatoid arthritis were excluded.

Women who had taken HRT regularly for six months or more after surgery were 38 percent less likely to require repeat surgery than those who had not done so. The authors also looked at patients who regularly took HRT for 12 months or more after their surgery, and these patients were more than 50 percent less likely to need revision surgery during the three year monitoring period of the study.

The findings also showed that taking HRT before surgery had no effect on the risk of implant failure.

Low levels of the female hormone estrogen have been implicated in bone thinning and loss, while HRT is thought to help conserve bone thickness. According to the authors, “Hormone replacement therapy and mid-term implant survival following knee or hip arthroplasty for osteoarthritis: a population-based cohort study” is the first study to show that HRT can help prevent repeat surgery in women who have undergone hip/knee replacement.