How Old is Too Old? Outcomes of Primary Total Knee Arthroplasty in Patients 70 Years or Older.

Introduction: Despite the increasing demand for total knee arthroplasty (TKA) in elderly patients, outcomes in this demographic remain uncertain due to their higher comorbidity burden and perioperative risks. This study aimed to assess and compare patient-reported outcomes (PROMs), readmission rates, and complications after primary TKA in elderly patients (aged 70 years or older at the time of surgery) versus a matched cohort of younger patients aged <70 years. Materials and Methods: This was a retrospective review conducted on patients who underwent primary unilateral TKA between 2016 and 2021 at a high-volume tertiary center. Two age cohorts, patients aged ≥70 years and patients <70 years, were matched for gender and body mass index. Outcomes measured included PROMs using Oxford knee score (OKS), readmission rates, and complications at a minimum 1-year follow-up, and statistical analyses were performed. Results: Of the 1028 elderly patients included, a readmission rate of 4.5% and a mortality rate of 2.4% were noted within the 1st year, compared to 1.07% and 0.6% in the younger cohort. Both elderly and younger patients showed significant improvement in OKS (mean improvements: 22.24 points in the elderly group and 19.81 points in the younger group). Patients with higher Charlson comorbidity index scores demonstrated a significantly increased risk of both readmission and mortality in both age groups (P < 0.001). Conclusion: TKA provides significant functional improvement in patients aged 70 years or older, though they face higher risks of readmission and mortality. Pre-operative optimization of comorbidities and a tailored rehabilitation plan are essential to maximize benefits and minimize risks.