TOTAL KNEE ARTHROPLASTY IN NONAGENARIANS: A COMBINED RETROSPECTIVE REVIEW FROM TWO HEALTHCARE SYSTEMS

Introduction Total knee arthroplasty (TKA) is an effective and durable operation for the management of end-stage osteoarthritis. The American Joint Replacement Registry reports the mean age for TKA is 67.4 years ± 9.4, with nonagenarians representing <1% of TKA. However, some have questioned the safety of arthroplasty in the elderly populations, suggesting an increased risk profile compared to younger counterparts. The objective of this study is to determine the rate of primary TKA in nonagenarians, is it prudent to operate on this cohort, and what is the one-year morbidity and mortality. Our hypothesis is that while nonagenarians may have more comorbidities, TKA is a safe and effective procedure. Methods We performed a retrospective review of all TKAs performed between 2010–2024 across two healthcare networks. Internal databases were queried for CPT code 27447. Pre-operative, peri-operative, and post-operative data was collected. A total of 14,994 primary TKAs were identified with 31 TKA procedures (0.21%) in patients 90 year of age or older. The average age was 91.6 years (IQR 90-94y) with 24 females (77.4%) and 7 males (22.6%); the average BMI was 25.5 ± 4.9 (range 18.1-37.5). The American Society of Anesthesiologists (ASA) score was 2 for 10 patients (32.2%), 3 for 20 patients (64.5%), 4 for one patient (3.2%). Pre-operative comorbidities included 2 patients (6.5%) with congestive heart failure and 9 patients (29%) with hypertension. Results The review of the registry data was through March of 2024, with an average follow-up length was 3.5 years (range 0.8-13.8 years). No patients were found to have expired within the first year of follow-up. Three patients (9.7%) were readmitted within 30 days: one for a traumatic rupture of the quadriceps tendon requiring reoperation, one for vasovagal syncope, and one for superficial cellulitis which resolved with antibiotics. No patients experienced any thromboembolic events, and there were no revisions or implant related complications. Discussion The number of nonagenarians is expected to increase due to improvements in healthcare with an increase in primary TKAs and our observations reveal that TKA is a safe procedure in this cohort who appear to be physiologically younger than their chronologic age. While our observed rate of surgery was low (0.21%) relative to the entire population within the combined database, with improvements in pre-operative optimization and peri-operative care, TKA in nonagenarians has a low peri-operative morbidity and mortality rates. There were also no revisions or implant related re-operations suggesting that the implant should outlive the patient. The limitation of this study is that it is retrospective database review with the possibility of missing or incomplete data, limited follow up and no functional outcomes. However, our observations did reveal that TKA is a safe and effective procedure in healthy nonagenarians.