The purpose of this study is to examine the relationship between isokinetic strengths, subjective knee scores, and functional performance in patients with an ACL-reconstructed knee. Methods: Fifty-five male patients between the ages of 16~53 years were enrolled in this study. At the time of testing, a mean 19.7 months had elapsed since the patients had received ACL reconstruction. Muscle strength of the affected knee was measured using an isokinetic dynamometer at the following velocities; 60, 180, 240°/s. The patients scored their affected knee function using 3 subjective knee scores: Lysholm, IKDC, and the Tegner Scores. Functional performance of the affected knee was measured using the one leg hop test for distance. Results: Isokinetic measurements showed a significant correlation only with the Tegner score. At 60°/s, peak torque (r=.322, p <.05) and peak torque to weight ratio, also written as peak torque % body weight (r=.395, p <.01), were positively correlated with the Tegner score. At 180°/s, peak torque % body weight (r=.336, p <.05), total work (r=.354, p <.05), and total work % body weight (r=.400, p <.01) were positively correlated with the Tegner score. At 240°/s, peak torque % body weight (r=.304, p <.05), total work (r=.318, p <.05), and total work % body weight (r=.331, p <.05) were positively correlated. At 60°/s, all isokinetic measurements for both extensors and flexors were significantly correlated with the functional performance of that knee (p <.01), of which the total work % body weight showed the strongest correlation (r=.600, p <.001). At 180°/s, all isokinetic measurements, except for total work by flexor muscles, were significantly correlated with functional performance (p <.05). At 240°/s, all isokinetic measurements were significantly correlated with functional performance (p <.05). Conclusion: The clinical information derived from measuring total work, as a reflection of knee function, has been undervalued and is as good as that derived from peak torque.
- Anterior cruciate ligament reconstruction
- Functional performance test
- Isokinetic test
- Subjective knee score