Yang Xiao1,2, Ming Ling3, Zhenming Liang1, Jian Ding4, Shi Zhan4, Hai Hu5, Bin Chen6. 1. Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No. 1838 North Guangzhou Avenue, Guangzhou, 510515, Guangdong, China. 2. Department of Orthopedics, Academy of Orthopedics Guangdong Province, Guangzhou, China. 3. Department of Orthopaedics, Fudan University Affiliated Huadong Hospital, Shanghai, China. 4. Department of Orthopedic Surgery and Orthopedic Biomechanical Laboratory, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. 5. Department of Orthopedic Surgery and Orthopedic Biomechanical Laboratory, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. xmhuhai@hotmail.com. 6. Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, No. 1838 North Guangzhou Avenue, Guangzhou, 510515, Guangdong, China. chb@smu.edu.cn.
Abstract
PURPOSE: Little is known about the in vivo forces and stresses on grafts used in anterior cruciate ligament (ACL) reconstruction. The aims of this study were to evaluate and compare the forces and stresses on grafts used in anatomical single-bundle ACL reconstruction at different locations of the femoral footprint (anterior vs middle vs posterior; high vs middle vs low) during a lunge motion. METHODS: Establish subject-specific finite element models with different graft's tunnel loci to represent the primary ACL reconstructions. A displacement controlled finite element method was used to simulate lunge motions (full extension to ~ 100° of flexion) with six-degree-of-freedom knee kinematics data obtained from the validated dual fluoroscopic imaging techniques. The reaction force of the femur and maximal principal stresses of the grafts were subsequently calculated during knee flexion. RESULTS: Increased and decreased graft forces were observed when the grafts were located higher and lower on the femoral footprint, respectively; anterior and posterior graft placement did not significantly affect the graft force. Lower and posterior graft placement resulted in less stress on the graft at higher degrees of flexion; there were no significant differences in stress when the grafts were placed from 0° to 30° of flexion on the femoral footprint. CONCLUSION: The proposed method is able to simulate knee joint motion based on in vivo kinematics. The results demonstrate that posterior to the centre of the femoral footprint is the strategic location for graft placement, and this placement results in anatomical graft behaviour with a low stress state.
PURPOSE: Little is known about the in vivo forces and stresses on grafts used in anterior cruciate ligament (ACL) reconstruction. The aims of this study were to evaluate and compare the forces and stresses on grafts used in anatomical single-bundle ACL reconstruction at different locations of the femoral footprint (anterior vs middle vs posterior; high vs middle vs low) during a lunge motion. METHODS: Establish subject-specific finite element models with different graft's tunnel loci to represent the primary ACL reconstructions. A displacement controlled finite element method was used to simulate lunge motions (full extension to ~ 100° of flexion) with six-degree-of-freedom knee kinematics data obtained from the validated dual fluoroscopic imaging techniques. The reaction force of the femur and maximal principal stresses of the grafts were subsequently calculated during knee flexion. RESULTS: Increased and decreased graft forces were observed when the grafts were located higher and lower on the femoral footprint, respectively; anterior and posterior graft placement did not significantly affect the graft force. Lower and posterior graft placement resulted in less stress on the graft at higher degrees of flexion; there were no significant differences in stress when the grafts were placed from 0° to 30° of flexion on the femoral footprint. CONCLUSION: The proposed method is able to simulate knee joint motion based on in vivo kinematics. The results demonstrate that posterior to the centre of the femoral footprint is the strategic location for graft placement, and this placement results in anatomical graft behaviour with a low stress state.
Entities:
Keywords:
Anterior cruciate ligament; Femoral tunnel; Finite element analysis; Fluoroscopy; Force; In vivo; Stress
Authors: Bailiang Chen; Tryphon Lambrou; Amaka C Offiah; Pedro A Gondim Teixeira; Martin Fry; Andrew Todd-Pokropek Journal: Int J Comput Assist Radiol Surg Date: 2012-12-02 Impact factor: 2.924