Two studies were carried out after anterior cruciate ligament (ACL) reconstruction to determine the effect of a knee brace on coordination (test 1) and electromyographic muscle activity in drop jumps (test 2). Test 1 studied 25 patients with ACL reconstruction under three test conditions (one-leg static, two-legged static, two-legged dynamic) compared with a control (n=30). The results showed highly significant improvements in all braced conditions. In test 2 ten patients with ACL reconstruction and ten healthy subjects performed a two-legged drop-jump; this was repeated 15 times and again 15 times with a knee brace worn on the reconstructed limb. Changes in electromyographically determined muscle activity (vastus medialis, vastus lateralis, biceps femoris, gastrocnemius) were observed, but they were significant in only few cases because of high variability. Drop-jumps with knee brace improved jumping height, increased the maximum knee angle in the ground contact phase, and reduced the maximum knee angle in the landing phase. Patients thus develop an increased confidence in the stability of their knees. We conclude that the benefits of the knee brace are due to the mechanical action, an enhanced coordination, and a psychological effect.

Many studies have shown that ACL-surgery leads to a decrease of proprioception abilities. In spite of the resulting high importance of coordinative exercise, there is nothing like a phase specific concept for coordinative training after ACL-operations going along with rehabilitation. Following a model, including all coordinative abilities, and a current after-care concept of ACL-surgery, the presented method is based on different categories of coordinative demands.

In 25 test persons with Anterior-Cruciate-Ligament (ACL)-Operation the sensomotory capabilities of the affected and the unaffected side were examined by KAT 2000 (BREG Inc., Vista, C.A., USA) with and without knee-brace (Hypex knee-brace/Fa. Aircast-Europa GmbH). The results were compared with those of a control group. In all cases of test variations (both leg-static/both leg-dynamic/one leg-static) there were significant differences between testing with and without knee brace. In the one leg-static test there was an improvement of 30% (p < 0.01), in the both leg-static test an improvement of 24% (p < 0.01). The both leg-dynamic showed a similar result (23.8%; p < 0.01). These noticed adaptations may be mediated by improvements of proprioceptive and exteroceptive capabilities and a positive impact on the anticipative control of behavior. The results of the control group differ in only a few cases from the results in the group of patients. This may be judged as indicator for the variety of sensomotory capabilities in the general population.

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