Correlation Analysis of KT 2000 arthrometer, Cybex Isokinetic Test and Lysholm Knee Score in ACL deficient knees

ABSTRACT

PURPOSE: The authors performed correlation analysis among the values of KT 2000 arthrometer, Cybex isokinetic test, and Lysholm knee score to reveal the clinical significance and their role in functional evaluation of ACL insufficiency. MATERIALS AND METHODS: Fifty-one patients with isolated ACL insufficiency were evaluated with KT 2000 arthrometer (15, 20, 30 lb, max.manual), Cybex isokinetic test (60 & 180 degrees/sec), and Lysholm knee score. Correlation analysis was performed between the values of the tests. RESULTS: The Lysholm knee scores had significant linear correlation with the values of KT 2000 of maximal manual difference (r=0.587, P<0.05). The Lysholm knee score had significant linear correlation with all the values of Cybex test of hamstring & quadriceps muscle weakness (r=0.585, 0.635, 0.656, 0.720, p<0.05). The degree of muscle weakness and maximum manual difference in KT 2000 did not show any linear correlation. The time lap between injury and evaluation did not show any correlation with any of the above parameters. CONCLUSION: Lysholm knee score appears to be mostly influenced by the degree of muscle weakness than anterior displacement. The values of KT 2000 of maximal manual difference revealed to be best correlated with Lysholm knee score. The time interval after injury cannot be clinically correlated with muscle weakness or Lysholm knee score.