Synovectomy of the knee. A comparative study between two post-operative regimens

ABSTRACT

The aim of this study was to compare the results of knee synovectomy with the use of two different post-operative regimens; cast immobilization then manipulation, and immediate continuous passive motion. It included 40 patients with rheumatoid knee synovitis. In all of them, open knee synovectomy was done through a midline skin incision. Post-operatively, patients were randomized into two groups; the first group [Cast group] included 20 patients who had a long leg cast applied for two weeks. After that, the cast was removed and the knee manipulated gently under general anaesthesia. In the second group [CPM group], continuous passive motion started immediately post-operatively, using CPM machine for three hours, three times daily, seven days a week. Knee swelling was assessed by measuring the mid-patellar circumference. The quadriceps muscle bulk was determined by measuring the mid-thigh circumference. The patients were followed-up at 3 months, 6 months and one year. At the final follow-up, the range of knee flexion was significantly better in patients of CPM group compared to those of immobilization group [93.6° and 91.5° respectively]. The knee joint swelling was less in CPM group [44.5 cm] than in cast group [45.2 cm], the difference was statistically significant. Quadriceps wasting was no significant between the two groups; 50.2 cm in the cast group, and 53.5 cm in CPM group. Wound gapping occurred in 3 patients in immobilization group and one patient in the CPM group. It was concluded that the use of continuous passive motion in the early post-operative period following open knee synovectomy is a reasonable choice