Rheumatoid Arthritis Patients Achieve Better Satisfaction but Lower Functional Activities as Compared to Osteoarthritis Patients After Total Knee Arthroplasty.

BACKGROUND: Recently, poor patient satisfaction after total knee arthroplasty (TKA) has gained attention mainly in osteoarthritis (OA) patients; however, satisfaction after TKA remains to be understood in rheumatoid arthritis (RA) patients. This study aimed to examine satisfaction and function after RA TKA using patient-reported outcome measures and to compare the results with those of OA-TKA.
METHODS: This study enrolled 534 TKAs of 501 patients consisting of 75 TKAs of 70 RA patients and 459 TKAs of 431 OA patients. Data of patient-reported outcome measures such as new Knee Society Score 2011, Pain Catastrophizing Scale, and Pain DETECT Score were collected at 2 years. Multiple regression analysis was performed with Knee Society Score satisfaction score set as a dependent variable in order to clarify factors affecting patient satisfaction. Principle component analysis was performed, and satisfaction and function components were compared between RA and OA.
RESULTS: All activity scores were significantly lower in RA TKA than in OA TKA, whereas the range of motion and patient satisfaction scores were significantly better in RA TKA than in OA TKA. Scores for symptom, expectation, basic activity, and discretional activity positively affected patient satisfaction (P < .001), while Pain Catastrophizing Scale negatively did (P = .021). Importantly, diagnosis of RA itself pushed up the patient satisfaction score by 1.5 points. Principle component analysis revealed that RA TKA achieved significantly higher satisfaction component (P = .001), but lower function component (P < .0001) compared to OA TKA.
CONCLUSION: Patient satisfaction was better but functional activity was lower in RA than in OA. As poor functional activity was evident preoperatively in RA patients, to improve functional outcome should be future challenge for RA TKA.