APPLICATION OF FUNCTIONAL DYNAMIC TESTS IN THE LATE POSTOPERATIVE PHASE AFTER ACL-SURGERY FOR THE EVALUATION OF KINEMATIC AND NEUROMUSCULAR PARAMETERS

Abstract

Functional dynamic tests have been developed for the evaluation of neuromuscular deficits In the late postoperative phase (1 year) after knee ligament surgery. Eight patients after ACI.surgery and 10 controls performed two different tests: 1) One-legged drop jumps from a height of 17cm. 2).Descending a stair from a height of 40cm. For the drop jumps contact time, flight time, maximal knee joint angle, range of motion and knee angle speeds were recorded as kinematic parameters. For the stairs maximal knee joint angle, range of motion and knee angle speed for the excentric phase were determined. The kinematic data was used to subdivide the movement into single phases (preinnervation, reflex induced activity, excentric, concentric (for the drop jumps)) for comparison of the determined parameters. For the knee extensor muscles the percentual integrated electrical activity of the knee extensor muscles (V.,medialis, V.lateralis, Rectus femor~sw) as calculated in relation to the normed total activity. The data of the M.biceps femoris, M.tibialis anterior and the medial head of the M.gastrocnemius was also integrated in relation to the determined movement phases. In the drop jump movement the patients showed significantly longer contact times (+60ms, p<.01), shorter flight times (-70ms, p<.Ol) smaller knee joint angles (-1 1 , p< 001) and slower joint speeds (-45"/s, pt05) in the operated leg. The perceptual part of the vastus medialis was significantly reduced in nearly all movement phases (-13,3% in,the excentric phase (p<.05) and -14,4% in the concentric phase (p<.001). Noticable is an increased activity of the v.lateralis in the excentric (+11,5%, p<.05) and the concentric phase (+8,5%, n.s.) of the movement. Descending the stair revealed no significant differences considering the kinematic parameters and the neuromuscular parameters of all measured muscle activities. The shift in the distribution of the perceptual activities of the quadriceps parts in the drop jump test is interpreted as a compensatory change of the movement pattern following a recruitment deficit of the M.vastus medialis. The lack of differences in the less dynamic stair descending movement shows the low selectivity of this test for patients in the late postoperative phase.