The Rolimeter: a new arthrometer compared with the KT-1000

A new simple and portable arthrometer, the Rolimeter, was used to assess th e anterior laxity of knees in 20 normal subjects and 18 subjects with chron ic anterior cruciate ligament (ACL) deficiency. The subjects were tested by one examiner using maximum manual force. In order to assess the reliabilit y of the device the same subjects were tested with the KT-1000. In ACL-defi cient knees the absolute translation and the side-to-side difference did no t differ significantly between the devices. In normal knees the Rolimeter m easured slightly smaller translations than the KT, but with a high degree o f correlation between devices. If a 3-mm or greater side-to-side difference is considered indicative of ACL deficiency, both arthrometers were success ful in diagnosing 16 of 18 cruciate ruptures (sensitivity 89%) and 19 of 20 normal knees (specificity 95%). We conclude that the Rolimeter, when compa red with the KT-1000, provides a valid measure of anterior knee laxity.