The Five-Year Outcomes of Total Knee Arthroplasty in Patients Who Have Cancer.

BACKGROUND Cancer prevalence has largely risen as better survivorship has allowed more patients to live into older adulthood. Total knee arthroplasty (TKA) is a widely performed and increasingly common procedure for end-stage arthritis, and while 90-day outcomes in cancer patients have been described, little is known about outcomes beyond five years. Given the known effects of cancer on bone structure and immunity, this study evaluated implant survival and functional outcomes at five years post-TKA in patients who had cancer compared with a matched cancer-free cohort.

METHODS A retrospective cohort analysis was conducted with a large national database. All adult patients undergoing TKA between July 2002 and July 2020 were identified and grouped by cancer history at the time of surgery. Cohorts were propensity score-matched 1:1 to mitigate differences in baseline demographics and comorbidities. The database identified 134,358 total patients undergoing TKA, of whom 8,937 had a current or previous diagnosis of cancer. After matching, each cohort consisted of 8,709 patients. The primary outcomes at five years included periprosthetic fracture, infection, aseptic loosening, instability, osteolysis, polyethylene wear, myositis ossificans, postoperative pain due to implant, fibrosis due to implant, heterotopic ossification, stiffness, and other instability. Odds ratios (OR) with 95% confidence intervals (CI) were calculated.

RESULTS At five years, patients who had cancer had significantly higher odds of infection due to prosthesis (2.60 versus 2.10%; OR 1.22, 95% CI: 1.00 to 1.48), aseptic loosening (1.10 versus 0.80%; OR 1.36, 95% CI: 1.00 to 1.83), and stiffness (5.00 versus 3.30%; OR 1.56, 95% CI: 1.34 to 1.81). There were no significant differences observed for other complications.

CONCLUSION A history of cancer was associated with increased five-year risk of periprosthetic infection, aseptic loosening, and stiffness after TKA. These findings highlight the need for tailored perioperative optimization, infection prophylaxis, and structured long-term surveillance in this high-risk population.