Intratester and intertester reliability of the KT-1000 arthrometer in the assessment of posterior laxity of the knee

We measured tibial translation in the knees of 22 subjects with posterior cruciate ligament tears or reconstructions by using the KT-1000 arthrometer. To assess the reliability of the device, two testers made measurements. One tester was a novice and the second tester had substantial clinical experience with the KT-1000 arthrometer. The quadriceps neutral angle was found for the uninvolved knee. Anterior and posterior translation and total anterior-posterior excursion were then measured. The quadriceps neutral angle was then reproduced in the involved knee and the same measurements were taken. Each subject was tested twice by each tester. The intraclass correlation coefficient values for the novice, experienced, and intertester reliability were 0.67, 0.79, and 0.62, respectively, for corrected posterior translation; 0.59, 0.68, and 0.64, respectively, for corrected anterior translation; 0.70, 0.74, and 0.29, respectively, for quadriceps neutral angle; and 0.84, 0.83, and 0.62, respectively, for total anterior-posterior excursion. Ninety-five percent confidence intervals for the novice, experienced, and intertester reliability were ±2.95, ±2.53, and ±3.27 mm, respectively, for corrected posterior translation; ±3.99, ±3.89, and ±3.74 mm, respectively, for corrected anterior translation; and ± 10.70°, ± 11.73°, and ±16.25°, respectively, for quadriceps neutral angle. The KT-1000 arthrometer was found to be a moderately reliable tool for the measurement of tibial translation in patients with posterior cruciate ligament tears and reconstructions.