Genucom, KT-1000, and Stryker knee laxity measuring device comparisons: Device reproducibility and interdevice comparison in asymptomatic subjects

Generally, three devices (the Genucom Knee Analysis System, the MEDmetric KT-1000 Arthrometer, and the Stryker Knee Laxity Tester), which have been pre sented in the literature, may be used to assess clinically the amount of knee laxity in an objective manner. This study compared the reproducibility of the anterior and posterior knee laxity values for each and made direct comparisons of the results obtained. Thirty asympto matic subjects were given a test-retest protocol on both legs with all three devices. Devices were tested in a counterbalanced order. Repeatability of test values within devices was variable, but all were acceptable, the lowest being r = 0.74. Analysis of variance (AN- OVA), and correlational analysis revealed that device- specific anterior and posterior laxity values were pro duced. We concluded that each commercially available knee laxity testing device can provide reproducible quantitative measurements of knee laxity; however, due to differences in device sensitivities and functional design, numerical results from one device cannot be generalized to another device.