Training Delayed Isokinetics in the Surgical Reconstruction of the Anterior Cruciate Ligament: a Case Study

INTRODUCTION: Isokinetic testing is a commonly utilized tool for the assessment of muscular performance in the physiotherapy and sports medicine setting. Isokinetics are frequently chosen because of their inherent patient-safety, objectivity, and reproducibility in testing measures (Dvir, 1995). Numerous authors have documented clinical outcome studies utilizing peak torque (PT) parameters, especially the bilateral comparison ratio of the quadriceps and hamstrings muscles peak torque measurements (Wilk et al., 1994). Human movements, especially sports movements, utilize a series of accelerating and decelerating limb movements that are accomplished through concentric, eccentric, and static muscular contractions. While running the limb is constantly accelerating and decelerating to accomplish body propulsion (Stanton et al., 1989). Therefore, the neuromuscular system monitors and controls these continued changes in limb angular velocity. This complex function is accomplished through the interaction of afferent neurological input and the ability to cause change through efferent output, which produces a muscular response. Thus, the neurophysiologic integrity of the muscles is critical in the assessment of the contractile tissue, and traditional isokinetic test data interpretation (i.e., PT) may not adequately assess normal muscular function (Davies, 1992). Thigh muscle atrophy secondary to immobilization or surgery is one of the well-known sequelae after treatment of all kinds of knee ligament injuries. Grade III sprains of the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), treated either conservatively or operatively, result in a 10% to 35% strength deficit of the quadriceps and hamstrings muscles (Kannus et al., 1992). There are, however, no detailed quantitative studies concerning the long-term effects of grade II knee ligament sprains or surgical reconstruction on muscle function, despite the fact that the development of commercial isokinetic testing dynamometers has made it possible to adequately measure thigh muscle function at orthopaedic and sport injury clinics (Kannus, 1990 and Dvir et al., 1989). The purpose of this work is to study the effect of training isokinetics on the PT of the femoral quadriceps and hamstrings muscles three years after surgical reconstruction of ACL.