Increased Periprosthetic Joint Infection Rate Following Total Knee Arthroplasty in Rheumatoid Arthritis Patients: Insights From a Japanese Nationwide Medical Claims Database Study

Introduction: Advances in pharmacological treatments have reduced joint deformities in rheumatoid arthritis (RA), leading to a decline in total knee arthroplasty (TKA) among RA patients. However, RA remains associated with higher risks of postoperative complications. This study compares postoperative complications during hospitalization in patients with RA and osteoarthritis (OA) undergoing TKA in Japan. Methods: This retrospective cohort study utilized data from the Japanese Diagnosis Procedure Combination database from April 2016 to March 2023. Patients who underwent TKA were identified, and propensity score (PS) matching was performed to balance age, sex, body mass index, simultaneous surgeries, and comorbidities, resulting in 9048 matched pairs. Outcomes included periprosthetic joint infections (PJI), cognitive dysfunction, deep vein thrombosis (DVT), pulmonary embolism (PE), and periprosthetic fractures. Statistical analyses were conducted using multivariate logistic regression with a significance threshold of p < 0.01. Results: RA patients had higher risks of PJI (odds ratio [OR]: 1.473, 95% CI: 1.134–1.912, p = 0.004) and postoperative cognitive dysfunction (OR: 1.721, 95% CI: 1.190–2.488, p = 0.004) compared to OA patients. In contrast, no significant differences were observed in the incidence of DVT, PE, or periprosthetic fractures. Conclusion: RA patients undergoing TKA are at increased risk of PJI and cognitive dysfunction, highlighting the need for tailored perioperative management. These findings provide important insights into optimizing outcomes for RA patients.