Reducing the Risk of Implant Failure: Hormone Replacement Therapy and Orthopedic Services

Just one year ago, doctors and researchers alike were puzzled by the fact that women who underwent hip-replacement surgery were almost 30 percent more likely than men to need repeat surgery within the first three years.

Because of ongoing negligence litigation against the manufacturer of one hip-replacement model, the focus tended to be on the replacement itself, rather than on the patients. That was until a study of more than 35,000 patients found that, no matter what model was used, women who received this type of orthopedic service experienced replacement failure more often.

The statistic was all the more troubling because the majority of the more than 400,000 Americans who undergo full or partial hip replacement surgeries each year are women.

Co-author of the 2013 study, Dr. Art Sedrakyan, associate professor of public health at Weill Cornell Medical College in New York City, said that, although the overall risk of the surgery remains low, "What we've observed is, regardless of size, women had higher rate of revision occurrence."

One year later, researchers may have found a treatment that can lower the risk of joint-replacement failure for women overall. In other words, while the 2013 research focused on hip replacement, new research indicates there could be a way to help women avoid a second surgery after any joint replacement. According to a new British study published online in Annals of the Rheumatic Diseases, hormone replacement therapy offers significant promise.

Implants fail for several reasons, but the most common is osteolysis, which results from bone loss caused by inflammation that occurs when small particles from the implant irritate the supporting bone.

In order to prevent this bone loss, researchers tried administering bisphosphonates, the class of drugs typically used to treat osteoporosis; drugs like Actonel,Fosamax andBoniva. However, bisphosphonates are associated with rare but serious side effects, so they decided to look at hormone replacement therapy (HRT) instead due to its ability to relieve symptoms of menopause, including thinning bones.

They looked at the records of women undergoing a first hip or knee replacement between 1986 and 2006. Of the 24,733 women who had joint surgery, they selected 2,700 who had used HRT for at least six months before or after the surgery and matched them with 8,100 nonusers. Then they followed the two groups for at least three years.

At the end of the study, 168 women from the original group had undergone revision surgery. After accounting for control factors such as age, weight, the type of joint replacement, and other drugs the patients were taking, results indicated that women who used HRT for at least six monthsafterthe original joint replacement were 38 percent less likely to need a repeat procedure than those who had not used HRT.

Results improved over time too. For those who continued taking HRT for a year, odds of needing a second surgery decreased an additional 10%.

As lead researcher, Dr. Nigel Arden, director of musculoskeletal epidemiology at the University of Oxford in England, pointed out, "There is evidence that drugs like hormone replacement therapy, used usually to prevent osteoporosis and fractures, might have a beneficial effect on implant survival in patients undergoing knee or hip replacement.”

"These findings must be confirmed in further studies, but they are consistent with previous reports by our group showing an association between use of other drugs that have similar effects on bone and the risk of implant revision [surgery],” he concluded.

Using HRT for any length of timebeforesurgery had no effect on bone loss or implant failure. In fact, Dr. Arden suggests that pre-surgical HRT could cause harm by preventing implants from anchoring properly to the bone. Additionally, he notes that hormone therapy should be stopped six weeks before surgery to reduce blood clot risk.

Even post-operatively, there are still side effects and risks associated with HRT such as blood clots and increased risk of certain cancers. Many women are reluctant to try it for that reason. Study results notwithstanding, the question remains as to whether the benefits related to joint replacement revision surgery outweigh those risks.

Elena Losina, PhD, codirector of the Orthopedics and Arthritis Center for Outcomes Research at Brigham and Women’s Hospital in Boston, calls the Oxford study "very well designed and executed using appropriate, modern analytic methods.”

However, she adds, "As [the study authors] highlighted, in order to consider these results more definitively in clinical practice, they need to be confirmed and reproduced in a multicenter, randomized controlled trial.”

Dr. Arden agrees. He points out that his study adds "a relevant piece of information for women who have received a total knee or hip replacement and are considering hormone replacement therapy for menopause. [But] it is only proof of principle and shouldn’t actually influence prescribing until [a randomized control trial] is performed.”

After all, while the risk to women of a second surgery is higher than for men, it is still small overall. Doctor Arden agrees that this is a consideration, but suggests women look at HRT as part of their healthcare in general, not just orthopedic services alone:

"Indeed, this is only a small added benefit of hormone replacement therapy. However, it is a relevant piece of information for women who have received a total knee or hip replacement and are considering hormone replacement therapy for menopausal symptoms.”

If you are a woman who has just begun seeking orthopedic services for joint pain, or are already considering or have decided to undergo joint replacement surgery, these study results are important.

If you are already considering HRT for other symptoms - especially osteoporosis - discuss with your doctor whether or not post-operative HRT would be right for you, or whether the HRT drugs you are already taking should be discontinued prior to surgery, then restarted as part of your recovery.

As with any surgery, it is important to talk with your doctor about any medications you are taking. Where orthopedic services like joint replacement surgery are concerned, there is promising new evidence that HRT may reduce your risk of needing a revision surgery by 40-50 percent.

As a 229-bed acute care hospital located in the heart of Slidell, LA, Slidell Memorial Hospital provides access to orthopedic services, as well as the latest treatments, technology and expert physicians.