The Effect of Patient Age and Surgical Appropriateness and Their Influence on Surgeon Recommendations for Primary TKA: A Cross-Sectional Study of 2,037 Patients

Background: Rising total knee arthroplasty (TKA) rates in younger patients raises concern about appropriateness. We asked: are younger individuals who seek consultation for TKA less likely to be appropriate for and, controlling for appropriateness, more likely to be recommended for surgery?

Methods: This cross-sectional study was nested within a prospective cohort study of knee osteoarthritis (OA) patients referred for TKA from 2014 to 2016 to centralized arthroplasty centers in Alberta, Canada. Pre-consultation, questionnaires assessed patients' TKA appropriateness (need, based on knee symptoms and prior treatment; readiness/willingness to undergo TKA; health status; and expectations) and contextual factors (for example, employment). Post-consultation, surgeons confirmed study eligibility and reported their TKA recommendation. Using generalized estimating equations to control for clustering by surgeon, we assessed relationships between patient age (<50, 50 to 59, ≥60 years) and TKA appropriateness and receipt of a surgeon TKA recommendation.

Results: Of 2,037 participants, 3.3% and 22.7% were <50 and 50 to 59 years of age, respectively, 58.7% were female, and 35.5% were employed. Compared with older participants, younger participants reported significantly worse knee symptoms, higher use of OA therapies, higher TKA readiness, and similar willingness, but had higher body mass index and were more likely to smoke and to consider the ability to participate in vigorous activities, for example, sports, as very important TKA outcomes. TKA was offered to 1,500 individuals (73.6% overall; 52.2%, 71.0%, and 75.4% of those <50, 50 to 59, and ≥60 years, respectively). In multivariate analyses, the odds of receiving a TKA recommendation were higher with greater TKA need and willingness, in nonsmokers, and in those who indicated that improved ability to go upstairs and to straighten the leg were very important TKA outcomes. Controlling for TKA appropriateness, patient age was not associated with surgeons' TKA recommendations.

Conclusions: Younger individuals with knee OA referred for TKA had similar or greater TKA need, readiness, and willingness than older individuals. Incorporation of TKA appropriateness criteria into TKA decision-making may facilitate consideration of TKA benefits and risks in a growing population of young, obese individuals with knee OA.

Clinical relevance: Younger people seeking TKA for knee OA had significant OA pain and disability despite recommended OA therapies, suggesting appropriateness for surgical consideration. However, they were significantly more likely to have morbid obesity, to smoke, and to consider return to vigorous activities, like sport, as important TKA outcomes. Whether the short- and longer-term risks of TKA are outweighed by the benefits is unclear and warrants additional research.