When discussing total joint replacement (TJR) with patients, I and most other surgeons who perform TJRs are invariably asked, “How long will my new hip last?’” or “Will I need to replace this new knee with another one if I live to be 90?” Although these important questions have essentially been studied since the implants and procedures were first developed, precise answers are still hard to come by. That’s largely because many factors can affect the longevity of an implant, including the implant material and design and the patient’s size/weight, activity level, and comorbidities. Also, many patients die before their joints wear out, and their data is often not captured accurately by researchers and registries. It is therefore difficult to give patients anything better than rough-estimate answers.
That is why I was interested to read two recently published systematic reviews in The Lancet. The reviews—one focused on knee replacement and the other on hip replacement—evaluated studies from six different non-US countries with robust joint registries in an effort to answer these “how long” questions. Based on the authors’ pooled analysis of registry data, the reviews found that:
- Nearly 60% of >215,000 hip replacements lasted 25 years, 70% lasted 20 years, and almost 90% lasted 15 years.
- The nearly 300,000 total knee replacements evaluated lasted even longer: 82% lasted 25 years, 90% lasted 20 years, and 93% lasted 15 years.
While these data are helpful, they do still not provide specific answers for the many individuals who may not be “standard” patients, and they do not take into account advances in implant designs and materials that have occurred over 25 years. However, as registry data becomes more ubiquitous and robust, especially in the United States with the growth of the American Joint Replacement Registry, I believe these questions will be answered with increased specificity for individual patients.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media