Long term restoration of peak torque, endurance and muscle activation post anterior cruciate ligament reconstruction

In recent years, Accelerated Rehabilitation (A.R.) protocols have been used following Anterior Cruciate Ligament (A.C.L.) reconstructions, the longer term effects of these programs are seldom analysed. This study examined musculoskeletal mechanisms that might affect long term functional restoration, the control subjects (n = 19) of mixed age and gender, had no previous knee deficiencies and were recreationally fit. The experimental subjects (n = 17) had undergone intra-articular A.C.L reconstruction, using bone patellar-tendon bone grafts performed by the same surgeon and had also participated in the A.R. protocol, similar to that described by Shelbourne and Nitz (1990). The experimental group attended Edith Cowan University (E.C.U.) research laboratory between 20-36 months post operation, where tl1ey participated in tests on a Cybex 6000 isokinetic dynamometer. Isokinetic knee extensions and flexions at 90, 180 and 300 degrees per second were performed, with torque output recorded from the hamstring and quadricep muscle groups, in the involved leg (l.N.) and in the uninvolved leg (U.N.). To examine quadriceps inhibition, maximal isometric contractions with twitch superimposition were analysed for each leg. Functional endurance was examined during repeated isokinetic contractions at 90 degrees per second for a duration of two minutes. To study muscle activation and co-activation, surface electromyography (S.E.M.G.) of the quadricep and hamstring muscle groups was recorded during all isokinetic contractions. 1be results from this study indicate that A.R. does not fully restore all long term musculoskeletal mechanisms that influence function. Compared to those of the uninvolved leg, the involved quadriceps were significantly deficiency whilst the hamstrings/ quadriceps ratio increased since the hamstrings peak torque did not diminish as much as the quadriceps peak torque. This long \term evaluation of muscle functions after A.C.L reconstructions, indicates a need for further research into surgical and rehabilitation procedures, that would enable complete restoration of all parameters and a return to maximal bilateral equality