Hormone Replacement Therapy Cuts Revision Risk 40%

What does hormone replacement therapy (HRT) have to do with repeat surgery for a knee or hip replacement? Apparently a lot, according to the results of a large population-based study published online in the Annals of the Rheumatic Diseases. The study found that HRT, taken regularly for six months after a knee or hip replacement, seemed to cut the risk of repeat surgery by around 40%.

The research team assessed the likelihood of repeat joint replacement surgery among women who required a first knee or hip replacement between 1986 and 2006. The details of their surgery had been entered into the primary care General Practice Research Database (GPRD), which holds millions of medical records for patients across the UK. The national data revealed that about 75% of the procedures had to be repeated because of osteolysis. Osteolysis occurs when particles from the implant seep into the surrounding tissue, prompting an inflammatory response which then destroys the bone around the implant.

More than 21, 000 women eligible for the study had not used HRT, while more than 3, 500 had done so for at least six months. The data provided matched samples of 2, 700 HRT users and 8, 100 women who had not used HRT. The researchers tracked the risk of repeat surgery in both sets of women for a minimum of three years.

Those who had taken HRT regularly for six months or more after their surgery were 38% less likely to require repeat surgery than were those who had not done so. Those who regularly took HRT for 12 months or more after their procedure were more than 50% less likely to need further surgery during the three year monitoring period.

Taking HRT before surgery made no difference to the risk of implant failure, the findings showed.

The authors of the study claim that this is the first study to show that HRT can help prevent repeat surgery in women who have undergone hip/knee replacements.