NYC Gazette

A recent study by the Hospital for Special Surgery (HSS) has concluded that active young adults who undergo total knee replacement are unlikely to need revision surgery in their lifetime. The findings were presented at the American Academy of Orthopaedic Surgeons 2025 Annual Meeting.

Dr. William J. Long, an HSS hip and knee surgeon and senior author of the study, noted, “As an increasing number of younger adults in their 40s and 50s consider total knee replacement, many wonder how long knee implants last before requiring a revision procedure.” He further stated, “The findings from our study—the largest and longest follow-up of patients under 55 undergoing total knee replacement—confirm that young patients can be confident their initial knee implants will allow them to pursue a high level of activity and more than likely last the rest of their lives.”

The longitudinal study followed patients aged 55 and younger who had total knee replacements between 1977 and 1992 using Insall-Burstein I and II prostheses. These designs, which provide posterior stability, were developed at HSS. Previous patient follow-ups occurred at intervals of 10, 25, and 30 years post-surgery.

For this final report, Dr. Long's team analyzed outcomes after 40 years for 81 patients aged between 33 to 55 years, covering a total of 107 knees. It was found that overall, 70% of these patients did not require revision procedures throughout their lives. Patients were significantly more likely to have passed away after four decades than to have needed a revision. Notably, among those with the original Insall-Burstein I prostheses, 80% avoided revision surgeries.

“Considering that today's knee replacements have addressed the pitfalls leading to the majority of revisions for mechanical issues in Insall-Burstein I and Insall-Burstein II implants, these are very reassuring findings," said Dr. Long.

In addition to examining six patients personally, lead author Aaron Weinblatt contacted others by phone. There were no indications of loosening or changes in symmetry or alignment of the original components observed during these interactions. Patients also reported improved levels of activity following surgery.

Patient-reported data showed improvements measured using the Tegner Activity Scale (TAS). Before surgery, the average TAS score was only 1.5; however, at the 40-year mark post-surgery, it increased to an average score of 2.7.

“Patients requiring a total knee replacement should not delay having surgery,” Dr. Long advised. “Our study results highlight that those who undergo knee replacement sooner are more likely to maintain a high level of activity that contributes to a healthy, longer-term lifespan.”

Dr. Long mentioned that a previous HSS study published in 2014 showed similar positive outcomes for those needing revisions at the time with an average TAS score of 3.0.