ACL-reconstructed and ACL-deficient individuals show differentiated trunk, hip, and knee kinematics during vertical hops more than 20 years post-injury.
OBJECTIVE
Little is known regarding movement strategies in the long term following injury of the anterior cruciate ligament (ACL), and even less about comparisons of reconstructed and deficient knees in relation to healthy controls. The present purpose was to compare trunk, hip, and knee kinematics during a one-leg vertical hop (VH) ~20 years post-ACL injury between persons treated with surgery and physiotherapy (ACLR), solely physiotherapy (ACLPT), and controls (CTRL). Between-leg kinematic differences within groups were also investigated.


METHODS
Sixty-six persons who suffered unilateral ACL injury on average 23 ± 2 years ago (32 ACLR, 34 ACLPT) and 33 controls performed the VH. Peak trunk, hip, and knee angles during Take-off and Landing phases recorded with a 3D motion capture system were analysed with multivariate statistics.


RESULTS
Significant group effects during both Take-off and Landing were found, with ACLPTdiffering from CTRL in Take-off with a combination of less knee flexion and knee internal rotation, and from both ACLRand CTRL in Landing with less hip and knee flexion, knee internal rotation, and greater hip adduction. ACLRalso presented different kinematics to ACLPTand CTRL in Take-off with a combination of greater trunk flexion, hip flexion, hip internal rotation, and less knee abduction, and in Landing with greater trunk flexion and hip internal rotation. Further, different kinematics and hop height were found between legs within groups in both Take-off and Landing for both ACL groups, but not for CTRL.


CONCLUSIONS
Different kinematics for the injured leg for both ACL groups compared to CTRL and between treatment groups, as well as between legs within treatment groups, indicate long-term consequences of injury. Compensatory mechanisms for knee protection seem to prevail over time irrespective of initial treatment, possibly increasing the risk of re-injury and triggering the development of osteoarthritis. Detailed investigation of movement strategies during the VH provides important information and a more comprehensive evaluation of knee function than merely hop height. More attention should also be given to the trunk and hip in clinics when evaluating movement strategies after ACL injury.


METHODS
Prospective cohort study, Level II.
Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, 901 87, Umeå, Sweden. jonas.markstrom@umu.se.
Jonas L
JL
Markström
Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, 901 87, Umeå, Sweden.
Eva
E
Tengman
Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, 901 87, Umeå, Sweden.
Charlotte K
CK
Häger
D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000534:rehabilitation / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009068:Movement; D026741:Physical Therapy Modalities; D011446:Prospective Studies; D016059:Range of Motion, Articular
Anterior cruciate ligament; Long-term; Movement strategy; One-leg vertical hop; Treatment