Total knee arthroplasty outcomes in patients with a history of radiation therapy.

Objective: There is limited information regarding how a history of cancer and related treatment with radiation therapy (RT) impacts outcomes after total knee arthroplasty (TKA). Therefore, our study assessed the risk of developing medical and surgical complications following TKA in patients with cancer as well as those with a history of prior RT.

Methods: Within a national federated research network, we conducted a retrospective cohort study, querying for patients who underwent a primary TKA from 2002 to 2022. Amongst these patients, we identified three pairs of cohorts: (1) those with and without a history of RT, (2) those with and without a cancer history, and (3) those with a history of cancer who were treated with and without RT. Following propensity-score matching for comorbidities, surgical and medical complications within the 30-day, 90-day, and 1-year postoperative periods were assessed.

Results: RT was associated with an increased risk of multiple medical complications. When controlling for cancer, patients receiving RT had lower odds of medical complications, and there was no association with these medical complications. Cancer patients had an increased risk of multiple medical complications including venous thromboembolism at all time-intervals. PJI risk was increased at 1-year among cancer patients that received RT compared to those that did not (OR: 1.5, 95% CI: 1.1-2.0).

Conclusions: While RT may not increase the risk of medical complications, a history of cancer was associated with adverse outcomes following TKA. Our findings serve to help educate this patient population and encourage collaboration with patients' oncologists during the pre-operative optimization process.