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Katie_Geers_Final_Thesis_07202022.pdf (4.61 MB)

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Oxford Rig Simulation for Analysis of the Effect of Posterior Tibial Slope Changes and Variable Ligament Stiffness on Knee Biomechanics

Geers, Katherine
http://rave.ohiolink.edu/etdc/view?acc_num=osu1658343963286504

Abstract Details

2022, Master of Science, Ohio State University, Mechanical Engineering.
Increased posterior tibial slope (PTS) has been shown to increase the risk of ACL injury. Anterior closing wedge proximal tibial osteotomy (ACWPTO) is a surgical procedure that involves removing a wedge of bone from the anterior part of the tibia to reduce the PTS and reduce the risk of anterior cruciate ligament (ACL) injury. Current ACWPTO technique literature does not agree on an ideal post-operative PTS range. Additionally, there is little quantitative justification for the post-operative ACWPTO slope values selected. Current research also does not examine the impact of variable ligament stiffnesses in combination with variable PTS. The goal of this research was to analyze the effect that variable ligament stiffnesses and variable PTS have on knee biomechanics with the goal of informing clinicians in the planning of ACLR and ACWPTO procedures. An additional goal was to define an optimal PTS range that would protect the knee from injury. This research utilized a previously validated Oxford Rig simulation of a deep squat to analyze the effect that varying PTS and knee ligament stiffness has on ACL force, ACL strain, anterior-posterior (A/P) translation, and medial-lateral (M/L) tibiofemoral (TF) contact location. 125 forward dynamics simulations were run representing 3 different ACL stiffnesses, 3 different PCL stiffnesses, 5 different knee types with variable collateral ligament and posterior capsule stiffnesses, and PTS values ranging from -0.484° - 14.516° representing both anterior tibial slope (negative PTS values) and posterior tibial slope (positive values). 86/125 of the simulations were successful. The stiffness of the collateral ligaments in the knee had little effect on the results. Additionally, the trends between ACL force, ACL strain, A/P translation and PTS were found to be linear. This made it difficult to identify a cut-off point to determine an ideal PTS range. In this study, the magnitudes of ACL force, ACL strain, and A/P translation contrasted previously published clinical values suggesting the ACL stiffnesses used in the study may have been too high. In general, increases in PTS resulted in greater ACL force, ACL strain, greater posterior A/P translation of the femur with respect to the tibia, and posterior translation of the M/L TF contact points. Increased ACL stiffness increased ACL force, decreased ACL strain and A/P translation, and resulted in anterior translation of the TF M/L contact locations. PTS changes generally affected ACL force and A/P translation, and the amount of femoral roll more than ACL stiffness. ACL stiffness had a dominant effect on the location of the M/L contact points in the TF joint. Both ACL stiffness and PTS dominated the results of ACL strain with stiffness having a dominant effect for loosening ACL stiffness relative to the middle stiffness, and PTS having a dominant effect for tightening ACL stiffness. Overall, this study identified general trends between PTS changes, ligament stiffness, and the results considered. This research was successful at quantifying how variable PTS and variable ligament stiffnesses affect knee biomechanics, and also developed a cruciate retaining Oxford Rig simulation that can be further improved and used in future studies. The results of this study can provide some insight for clinicians when considering ACWPTO procedures and ACLR.
Robert Siston (Advisor)
Yun-Seok Kang (Committee Member)
117 p.
Biomechanics; Biomedical Engineering; Mechanical Engineering
ACL Injury; Posterior Tibial Slope; PTS; ACWPTO; Anterior Closing Wedge Proximal Tibial Osteotomy; Biomechanics Simulations; Mathematical Knee Model; ACL; Anterior Cruciate Ligament; Knee

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Citations

  • Geers, K. (2022). Oxford Rig Simulation for Analysis of the Effect of Posterior Tibial Slope Changes and Variable Ligament Stiffness on Knee Biomechanics [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1658343963286504

    APA Style (7th edition)

  • Geers, Katherine. Oxford Rig Simulation for Analysis of the Effect of Posterior Tibial Slope Changes and Variable Ligament Stiffness on Knee Biomechanics. 2022. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1658343963286504.

    MLA Style (8th edition)

  • Geers, Katherine. "Oxford Rig Simulation for Analysis of the Effect of Posterior Tibial Slope Changes and Variable Ligament Stiffness on Knee Biomechanics." Master's thesis, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1658343963286504

    Chicago Manual of Style (17th edition)

osu1658343963286504
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