A comparison of pre-operative evaluation of anterior knee laxity by dynamic X-rays and by the arthrometer KT 1000.

The comparison of bilateral dynamic X-rays in passive anterior and posterior drawer with a load of 9 kg, and the arthrometer KT 1000 measurements obtained from 100 patients before anterior cruciate ligament reconstruction, confirms the good diagnostic efficiency of the following methods: (1) radiological measurement of the anterior translation of the medial compartment, as an absolute value and especially as a differential value in relation to the opposite, uninjured knee, the normal value limits being respectively 5 and 2 mm; and (2) arthrometric measurement of the maximal manual translation, also as absolute and differential values, the normal value limits being 10 and 2 mm respectively. These two measurements have a predictive value of 90%. No numerical equivalency exists between the radiological and arthrometric values, but their variations in relation to each other are statistically correlated. The arthrometer, simple to use and totally innocuous, is an excellent test device for consultation, while dynamic X-rays allow separate studies of each compartment to look for lesions of the posteromedial or posterolateral corners.