Relationship between chondral lesion and peak torque following anterior cruciate ligament reconstruction of the knee: case study

Context: The association between anterior cruciate ligament (ACL) injury and the development of secondary osteoarthritis has been the subject of several studies. Ligament injury predisposes joint cartilage lesions, thus influencing motor control and peak torque. Objective: To evaluate the influence of the degree of chondral lesion on peak torque of the anterior and posterior musculature of the thigh following ACL injury and reconstruction. Method: Six male subjects with total unilateral ACL injury were evaluated 24 hours before surgery and at two times after surgery (4.66 plus or minus 1.03 and 15.83 plus or minus 2.63 months, respectively). Isokinetic evaluations of knee flexion and extension were made in concentric mode, at velocities of 60 degree /s and 180 degree /s, and the variables of hamstring peak torque (HPT) and quadriceps peak torque (QPT) and hamstring/quadriceps ratio (H/Q) were analyzed. The modified Mankin histological scale was used to evaluate the macroscopic degree of chondral injury. The ANOVA statistical test (p less than or equal to 0.05) was used to compare the results between the three times studied, with the Newman-Keuls post-hoc test. Spearman's correlation test was then applied to evaluate the influence of the degree of chondral injury on the peak torque of the thigh musculature. Results: There were statistically significant differences in the H/Q ratio at the velocity of 60 degree /s (p= 0.01). The degree of chondral injury degree ranged from 1 to 5, although there was no correlation with the isokinetic findings. Conclusion: There was an imbalance in agonist/antagonist relationship, with regard to torque, between muscle groups of the knee following ACL reconstruction. However, the degree of secondary chondral lesion did not influence the progressive gains in this muscle groups over the study period.