Conservative versus operative Treatment after ACL-Rupture:: Influence on the muscle strength capability of the lower extremity

Purpose: In this study two groups of ACL-rupture patients having had a conservative or an operative treatment and a similar rehabilitation were compared regarding their muscle strength capabilities, and the clinical outcome. Methods: Thirty-three patients (mean age 31 years) were selected according to the Lysholm-scores. Twelve patients were conservatively treated (Group I) and were examined between six and 16 months post trauma. Group II consisted of 21 operatively treated patients which were examined between 6 and 16 months post surgery. All patients underwent a clinical exam following the OAK evaluation form and were tested on a Cybex 6000 isokinetic machine. The subjects had to perform concentric contractions of the extensor and flexor muscles of the knee, hip and ankle at 60 and 120 degrees/s. In addition the knee musculature was isometrically tested at knee angles of 0 and 45 degrees. Results: The clinical examination revealed significant (P < 0.05) differences between groups. The operatively treated patients scored better at the tests for ligamentous stability, whereas the testing of the muscular capabilities revealed significant differences (P < 0.05) favouring the conservatively treated patients in the isokinetic measures, (maximal concentric torque M-max,M-con) of the knee extensors, knee flexors, and ankle plantarflexors. Conclusion: Whereas the clinical examination only revealed the ligamentous stability to be better results in the operatively treated patients, the conservatively treated patients showed better results in the isokinetik strength measures of the knee extensors, knee flexors, and ankle plantarflexors. The better muscular profiles found for the conservatively treated patients suggest that a better regeneration of the corresponding muscular capabilities after an ACL rupture is possible, provided a specific and controlled rehabilitation program is performed. This seems to be more difficult in operatively treated patients even six to 16 months after the surgical intervention.