Assessing the limits of knee motion

Ten patients were examined clinically by 11 experienced knee surgeons and with three measurement devices (Genucom, Knee Signature System, and KT-1000). Nine of the 10 patients examined had sustained documented intraarticular ligament disruptions including eight ACL disruptions and five posterior cruciate ligament disruptions. The eight patients with ACL injuries had undergone reconstructive surgery. The clinical examination test sequence was performed as described by the International Knee Documentation Committee. Testing results were reported as estimated degrees of angulation or millimeters of displacement. Testing results were divided into two groups based on the index minus nonindex knee difference. Eighteen displacement tests were performed on each knee by each examiner. The index minus nonindex knee difference was greater than 3 mm in 16% of the tests. Only 1 of the 198 displacement tests performed on the subject who did not have a ligament disruption was recorded as an index minus nonindex difference greater than 3 mm. There was appreciable difference between measurements recorded by different examiners, particularly anterior/posterior measurements in patients who had sustained combined anterior and posterior cruciate ligament injuries. There is a need to rigorously evaluate limits of motion tests that are used to develop treatment plans and report the results of ligament surgery.