Peak Torque and Total Work Relationship in Thigh Muscles After Anterior Cruciate Ligament Injury.

Peak Torque and Total Work Relationship in Thigh Muscles After Anterior Cruciate Ligament Injury 

Kannus P (Univ of Tampere, Tampere, Finland), Journal of Orthopaedic and Sports Physical Therapy 10(3):97-101, 1988.

The purpose of this study was to analyze the relationship between peak torque and the total work output of the quadriceps femoris and hamstring muscles in patients with anteriorly unstable knee joints attributable to total loss of the anterior cruciate ligament (ACL). Thirty-six patients were verified under anesthesia, arthroscopy, or arthrotomy to have chronic anterior instability of one knee. Each subject's isokinetic peak torque was determined at 60 [degrees] and 180 [degrees]/sec using the Cybex [R] isokinetic dynamometer with microcomputer. The peak torque was measured at both test speeds, and the total work was measured at the 180-degree test speed. One minute after the isokinetic testing was complete, the maximum isometric extension and flexion strength was determined with a knee-flexion angle of 60 degrees from full extension. The mean and standard deviations of the quadriceps femoris and hamstring peak torques and work are reported in the given tables. The subjective and functional evaluation of each subject was performed using the Lysholm's knee scoring scale. Correlations between the peak torque and the total work were calculated at each test speed. The same correlation was used to determine the association between the peak torques, the total work, and the Lysholm score in the ACL-insufficient knees.

The results of this study revealed that at every test speed, 0 [degree], 60 [degrees], and 180 [degrees]/sec, the correlation coefficients between peak torque and total work were significant at p [is less than] .001 in both the uninjured and the ACL-insufficient knee. Both muscle groups in the uninjured and the ACL-insufficient knees had slightly higher correlation coefficients with the higher test speeds. The mean relative peak torque deficit of the hamstrings in the ACL-insufficient knee was 18 + 14%, and for the quadriceps femoris, 24 + 15%. Corresponding to the total work, the values were 25 + 20% and 31 + 19%. The Lysholm scores averaged 60 points + 21 points.

The conclusions of this study seem to demonstrate that in healthy as well as ACL-insufficient knees, the total work of the quadriceps femoris and hamstring muscles can be acceptably predicted from simpler measurements, the isometric and isokinetic peak torque analyses. The study also demonstrates that the peak torque and the total work of the quadriceps femoris and hamstring muscles show a significant correlation with the subjective and functional results when using the Lysholm scoring method.