Quantifying Temporal Changes in Knee Joint Laxity and Dynamic Knee Stability for Healthy and Acute ACL Injured Individuals
Date
2015-02-02
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Abstract
ACL rupture causes altered joint dynamics and leads to greater risk of joint degeneration and development of knee OA. The current study investigated relations amongst passive knee laxity and dynamic knee stability in healthy and ACLD individuals over time to understand adaptations following ACL rupture during a sub-acute stage post-injury. An in vivo MR based measure of passive knee laxity was obtained using a novel knee loading apparatus to image the knee joint under various loading conditions. Dynamic knee stability was evaluated during two dynamic tasks using the finite helical axis (FHA) approach to quantify kinematics, combined with wavelet analysis of muscle activity.
The healthy group demonstrated side-to-side differences in FHA measures not present in the ACLD group. This revealed asymmetrical movement in the healthy group and enabled appropriate interpretation of side-to-side differences due to ACL rupture. Passive knee laxity was larger in the ACLD injured limb compared to the healthy dominant limb at six weeks post-injury, and did not significantly change in the injured limb between six and twelve weeks post-injury. FHA measures in the ACLD injured limb were not significantly different from healthy at six weeks post-injury. However, the ACLD group demonstrated changes in both limbs in FHA measures and muscle power between six and twelve weeks post-injury suggesting bilateral adaptations to ACL rupture. These changes resulted in increased limb symmetry during the swing task, and decreased limb symmetry during the squat task. At twelve weeks post-injury, ACLD individuals revealed significant correlations between passive knee laxity and FHA measures not present in the contralateral limb or the healthy group. ACLD individuals with increased passive knee laxity demonstrated more constrained movement during the swing, and less constrained movement during the squat. Relationships amongst passive knee laxity and dynamic knee stability in the ACLD group provided an understanding of the influence of structural joint laxity on dynamic movement patterns. Early adaptations in the ACLD knee joint are speculated to contribute to the initiation of degenerative changes in the knee joint, which may be modifiable with targeted rehabilitation protocols aimed at minimizing or slowing the progression of OA.
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Engineering--Biomedical
Citation
Bishop, E. L. (2015). Quantifying Temporal Changes in Knee Joint Laxity and Dynamic Knee Stability for Healthy and Acute ACL Injured Individuals (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27500