Reduced knee joint moment in ACL deficient patients at a cost of dynamic stability during landing

• Published in: Journal of biomechanics Vol. 45; no. 8; pp. 1387 - 1392
• Main Authors: Oberländer, Kai Daniel, Brüggemann, Gert-Peter, Höher, Jürgen, Karamanidis, Kiros
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 11.05.2012; Elsevier; Elsevier Limited
• Subjects: Adult; Anterior cruciate ligament; Anterior Cruciate Ligament - physiopathology; Anterior Cruciate Ligament Injuries; Biological and medical sciences; Cartilage; Center of mass; Control equipment; Cost engineering; Diseases of the osteoarticular system; Dynamic stability; Feedforward control; Female; Gait; Humans; Injuries of the limb. Injuries of the spine; Kinematics; Knee; Knee Injuries - physiopathology; Knee Joint - physiopathology; Knee joint loading; Knees; Landing; Locomotion; Male; Margin of stability; Mechanics; Medical sciences; Miscellaneous. Osteoarticular involvement in other diseases; Patients; Physical Medicine and Rehabilitation; Range of Motion, Articular; Task Performance and Analysis; Torque; Traumas. Diseases due to physical agents; Trunks; Feedforward control; Margin of stability; Knee joint loading; Anterior cruciate ligament; Knee; Human; Pathophysiology; Diseases of the osteoarticular system; Trauma; Biomechanics; Tissue rupture; Dynamic stability; Biomedical engineering
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2012.02.029

Abstract The current study aimed to examine the effect of anterior cruciate ligament deficiency (ACLd) on joint kinetics and dynamic stability control after a single leg hop test (SLHT). Twelve unilateral ACLd patients and a control subject group ( n =13) performed a SLHT over a given distance with both legs. The calculation of joint kinetics was done by means of a soft-tissue artifact optimized rigid full-body model. Margin of stability (MoS) was quantified by the difference between the base of support and the extrapolated center of mass. During landing, the ACLd leg showed lower external knee flexion moments but demonstrated higher moments at the ankle and hip compared to controls ( p < 0.05 ) . The main reason for the joint moment redistribution in the ACLd leg was a more anterior position of the ground reaction force (GRF) vector, which affected the moment arms of the GRF acting about the joints ( p < 0.05 ) . For the ACLd leg, trunk angle was more flexed over the entire landing phase compared to controls ( p < 0.05 ) and we found a significant correlation between moment arms at the knee joint and trunk angle ( r 2 = 0.48 ; p < 0.01 ) . The consequence of this altered landing strategy in ACLd legs was a more anterior position of the center of mass reducing the MoS ( p < 0.05 ) . The results illustrate the interaction between trunk angle, joint kinetics and dynamic stability during landing maneuvers and provide evidence of a feedforward adaptive adjustment in ACLd patients (i.e. more flexed trunk angle) aimed at reducing knee joint moments at the cost of dynamic stability control.