Disease activity, knee function, and walking ability in patients with rheumatoid arthritis 10 years after primary total knee arthroplasty.

PURPOSE To evaluate disease activity, knee function, and walking ability of patients with rheumatoid arthritis (RA) over 10 years after total knee arthroplasty (TKA). METHODS Four men and 26 women (mean age, 59.9 years) underwent 42 TKAs for RA with a mean duration of 151.3 months and were followed up for a mean of 142.3 months. Preoperatively, disease activity was assessed by C-reactive protein (CRP) level only, and the range of knee motion was recorded. At the final follow-up, tender joint count, swollen joint count, visual analogue scale of RA symptoms, and the Modified Health Assessment Questionnaire (MHAQ) score were assessed. Disease activity was evaluated using CRP, matrix metalloproteinase-3, and Disease Activity Score. Range of motion and Knee Society knee and function scores were also assessed. RESULTS The use of methotrexate increased from 4 patients preoperatively to 20 patients at the final follow-up (p<0.001), and the mean dose increased from 3.9 to 6.3 mg/week (p<0.001). Among the 30 patients, the mean CRP level decreased from 2.63 mg/dl preoperatively to 0.61 mg/dl at the final follow-up (p<0.001). Disease activity was controlled. At the final follow-up, disease activity was in remission in 10 patients, low in 11, and moderate in 9. The mean Knee Society knee score was excellent (91.0), but the mean function score was poor (57.0) and diverse. Severe walking disability (function score, <40) was noted in 8 patients (11 TKAs). Knee and function scores did not correlate. CONCLUSION Walking ability in patients with RA after TKA was generally poor. Poor function was associated with a history of spinal or lower extremity fracture surgery and the MHAQ score.