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Human hip and knee torque accommodations to anterior cruciate ligament dysfunction
L R Osternig1, R Ferber, J Mercer
1Department of Exercise and Movement Science, University of Oregon, Eugene 97403, USA. louiso@oregon.uoregon.edu
European Journal of Applied Physiology
|November 10, 2000
Summary
Post-ACL surgery patients demonstrate altered biomechanics, utilizing hip extensors more than controls to compensate for anterior cruciate ligament (ACL) deficiency. This hip:knee extensor torque ratio is linked to reduced anterior tibia shear during exercise.
Area of Science:
- Biomechanics
- Orthopedics
- Sports Medicine
Background:
- Anterior cruciate ligament (ACL) deficiency and post-surgical states involve lower extremity functional adaptations.
- Compensation patterns may influence hip and knee joint mechanics, but variances are not fully understood.
Purpose of the Study:
- To assess hip:knee extensor torque ratios relative to anterior tibia shear in pre-surgical ACL deficient, post-surgical ACL, and uninjured subjects.
Main Methods:
- Measured hip and knee joint moments and anterior tibia shear during variable resistance exercise in 45 subjects (ACL deficient pre-surgical, post-surgical, and controls).
- Calculated anterior tibia shear using a model based on cadaver dissections and radiography.
- Tested subjects under varying cadences and resistance levels.
Main Results:
- Post-ACL surgical group exhibited significantly greater hip:knee extensor torque ratios compared to pre-surgical and control groups.
- Significant negative correlations found between hip:knee extensor torque ratios and anterior tibia shear across all groups.
- Anterior tibia shear decreased with increased speed, while the hip:knee extensor torque ratio increased with speed.
Conclusions:
- Post-ACL surgery patients compensate by increasing hip extensor usage in closed-chain exercises.
- The hip:knee extensor torque ratio is significantly related to anterior tibia shear.
- Increased exercise speed reduces anterior tibia shear in ACL deficient and post-surgical individuals.