Quantitative assessment of functional limitations in normal and anterior cruciate ligament-deficient knees

The purpose of this study was to evaluate the effectiveness of five hopping, jumping, and cutting-type (shuttle run) tests in determining lower extremity functional limitations in anterior cruciate ligament- (ACL) deficient knees. Ninety-three normal subjects were tested. No statistical significance was found between right and left lower limb scores (limb symmetry index) as related to sports activity level, gender, or dominant side. This allowed an overall symmetry index score to be established for the population as a whole. An 85% symmetry index score was found in more than 90% of the normal population for the one-legged hop for distance test and the one-legged timed hop test. Thirty-five patients with ACL-deficient knees were tested. The patients also had KT-1000 and Cybex testing and completed questionnaires rating symptoms, sports activity levels, and sports functional limitations. The cutting-type tests and the vertical jump test did not detect functional limitations in a reliable manner. In the one-legged hop tests, 50% of the patients performed normally, however, all reported giving-way episodes with sports, indicating a lack of sensitivity of these tests in defining functional limitations. Patients with abnormal one-legged hop test scores were considered at serious risk for giving way and limitations during sports activities. Statistically significant relationships were found among abnormal scores on the one-legged hop-type tests and (1) self-assessed difficulty with pivoting, cutting, and twisting, (2) quadriceps weakness (Cybex), and (3) patellofemoral compression pain.