Factors for the presence of anteromedial rotatory instability of the knee

• Published in: Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association Vol. 9; no. 4; pp. 380 - 385
• Main Authors: Kurimura, Makoto, Matsumoto, Hideo, Fujikawa, Kyosuke, Toyama, Yoshiaki
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 01.07.2004; Springer Nature B.V
• Subjects: Adolescent; Adult; Anterior cruciate ligament (ACL); Anterior Cruciate Ligament - physiopathology; Anterior Cruciate Ligament Injuries; Equipment Design; Female; Humans; Instability; Joint Instability - etiology; Joint Instability - physiopathology; Knee; Knee Joint - physiopathology; Ligaments; Male; Medial collateral ligament (MCL); Middle Aged; Physical Examination - instrumentation; Range of Motion, Articular; Tibial rotation; Knee; Tibial rotation; Instability; Anterior cruciate ligament (ACL); Medial collateral ligament (MCL)
• ISSN: 0949-2658; 1436-2023
• DOI: 10.1007/s00776-004-0797-0

Anteromedial rotatory instability (AMRI) of the knee joint was investigated with an instrument newly designed to simulate the manual AMRI test and to quantify its magnitude. Thirty healthy subjects, 20 patients with anterior cruciate ligament (ACL) injury, and 10 with both ACL and medial collateral ligament (MCL) injuries were examined. Using the instrument, 100 N of anterior force was applied to the proximal part of the tibia with the foot in neutral rotation, 30° of internal rotation, and 30° of external rotation, and the magnitude of anterior displacement was recorded. The measurement was carried out at 20° and 90° of flexion. A significant increase in anterior laxity was observed in all three rotation positions in the injured patients. However, the magnitude of laxity in external rotation was less than that in neutral rotation in the ACL injured patients, whereas it was the greatest in external rotation in ACL + MCL injured patients. Thus, we conclude that an injury involving both the ACL and MCL causes AMRI.