Cylinder or mobile cast brace after knee ligament surgery. A clinical analysis and morphologic and enzymatic studies of changes in the quadriceps muscle.

Sixteen patients participated in a prospective randomized trial in which a standard cylinder cast was compared with a mobile cast brace. Both were worn for 4 weeks, beginning at 1 week after reconstruction of the anterior cruciate ligament. The athletes that had used a cast brace could return to sports activities in about one-half the time it took for the athletes with a standard cast. The patients with a standard cast showed a significant atrophy of Type I (slow twitch) muscle fibers in the vastus lateralis. The cast brace patients did not show any significant changes in cross-sectional areas of Type I or Type II (fast twitch) muscle fibers. The standard cast patients had a significant reduction of succinate dehydrogenase (SDH) activity in the vastus lateralis whereas the patients with the cast brace did not show any significant changes. No difference in surgical end result was found. A cast brace with a limited range of motion between 20 and 60 degrees of flexion is recommended as the standard postoperative treatment after knee ligament surgery.