Over a Decade of Risk Reduction Following Total Knee Arthroplasty? Consecutively Evaluating the Relative Risk of Patient Factors and Postoperative Complications From 2011 to 2025

BACKGROUND The impact of perioperative risk optimization on adverse outcomes following total knee arthroplasty (TKA) has not been evaluated over time. We assessed absolute and relative risk reductions (ARR, RRR) of postoperative complications over the last decade in patients with established risk factors. METHODS Overall, 27,126 primary TKAs from our academic center between 2011–2025 were analyzed. Changes in length of stay (LOS) and home discharge were assessed over time. Absolute risk (AR) of 90-day readmissions, emergency department (ED) visits, and two-year revision risks were assessed for all patients and for patients with the following risk factors: age>70, body mass index (BMI)>40, smoking, and diabetes. We calculated ARR and RRR for each consecutive time interval relative to the initial interval. RESULTS Mean hospital length of stay decreased from 2.45 to 2.12 days (P = 0.06), while non-home discharge declined from 53.8% to 6.5% (P < 0.001). Compared with the earliest interval, 90-day readmission risk decreased overall for all patients (ARR −0.02, RRR 0.36, RR 0.64 vs baseline). The largest improvement was seen in patients with BMI > 40 (ARR −0.20, RRR 0.80, RR 0.20), followed by those with diabetes (ARR −0.03, RRR 0.58, RR 0.42). In contrast, age > 70 and smoking were associated with higher readmission risk over time (ARR +0.01 and +0.05; RR 1.19 and 2.42, respectively). 90-day ED visit risk increased for the cohort overall (ARR +0.03, RRR −2.30, RR 3.30). Increases were most pronounced among patients with BMI > 40 (ARR +0.05, RR 2.96) and diabetes (ARR +0.03, RR 1.81), whereas smokers had a small net reduction in ED risk by the final interval (ARR −0.02, RR 0.67). By 2023, two-year revision risk had declined for all patients (ARR −0.01, RRR 0.27, RR 0.73). The greatest reductions were observed in smokers (ARR −0.24, RRR 0.96, RR 0.04) and patients with BMI > 40 (ARR −0.14, RRR 0.82, RR 0.18), with smaller improvements among those with age > 70 (ARR −0.01, RR 0.83) and diabetes (ARR −0.01, RR 0.85). CONCLUSION Decreased readmission and revision risk in patients with established risk factors suggests improvement in perioperative risk optimization over the last decade. The increase in ED utilization without subsequent increase in readmission, alongside decreased LOS and non-home discharge, suggests the need for improved postoperative patient education and support during early recovery.