Leg muscle strength of both the operated and unoperated sides was measured before and after total knee arthroplasty (TKA) by the SLR test and gait ability was evaluated by the timed up & go test (up & go test). The results were compared between 16 patients with rheumatoid arthritis (RA) and 12 patients with knee osteoarthritis (OA). Patients were all female and their average age was 67.2 ± 9.0 years in RA patients and 70.8 ± 4.6 years in OA patients. Muscle strength was measured before operation, in full weight bearing (16.9 ± 2.6 days after operation), and at discharge (26.0 ± 2.9 days after operation) by a newly developed manual dynamometer. The degree of pain was also evaluated by Visual Analogue Scale (VAS). In RA patients, leg muscle strength of SLR test in full weight bearing reached almost the same value as that before operation, and was increased significantly at discharge. In OA patients, leg muscle strength of SLR test was decreased significantly in full weight bearing, and reached the same value as that before operation at discharge. Leg muscle strength of SLR test of OA patients correlated negatively with VAS. Compared with before operation, muscle strength of unoperated side in SLR test was increased both in full weight bearing and at discharge in RA patients, but was not significantly increased in full weight bearing and increased at discharge in OA patients. In up & go test, RA patients showed no difference in gait velocity between before operation and at discharge, but OA patients showed lower gait velocity at discharge than before operation. Depending on basic diseases, patients indicate different physical conditions before operation, and exhibit different recovery process even though the same operation and physical therapy are conducted. It is therefore necessary to prepare goal-setting and to proceed programs, which are suited for each disease.
