Developing Subject Specific Methods For Knee Joint Injury Detection Using Finite Element Analysis

Download or read book Developing Subject Specific Methods for Knee Joint Injury Detection Using Finite Element Analysis written by Alexander Dickerson Orsi and published by . This book was released on 2015 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anterior cruciate ligament (ACL) tear occurs upwards of 400,000 times annually in the U.S. Reconstructive surgery and rehabilitation combine to create an annual $1 Billion expense. Associated cartilage damage leads to degenerative osteoarthritis. Injury mechanism theories include risk factors such as specific motion combinations, unbalanced musculature, intercondylar notch impingement, and gender. Despite ongoing research into injury prevention, injury rates have not improved. Better understanding the injury mechanisms is important to improve medical procedures, and reduce rehabilitation costs. Subject specific injury analysis can determine motion combinations leading to soft tissue injury for individual patients. The importance of individualized injury detection stems from the unique tissue geometries seen in each patient. Subject specific modeling provides a way to account for these irregularities. This thesis describes techniques developed to investigate subject specific knee joint injury using finite element (FE) analysis. 3D FE knee joint models were developed to determine the combinations of motion leading to ligament and soft tissue injury. ACL tear and articular cartilage injury were monitored over a spectrum of knee joint motions. The relationship between femoral axial rotation and frontal plane valgus/varus rotation was determined for both injuries. External femoral rotation increased susceptibility for ligament failure compared to internal rotation. Frontal plane knee angles at ACL injury were lower in varus than in valgus. Surgical variations during ACLR are thought to affect success rates by increasing intercondylar notch impingement. Understanding how surgical variations affect impingement will provide insight into the high re-injury rates. A study was performed to determine how variations in graft size and insertion site location affect impingement. Several simulations were conducted using three ACL graft sizes and polar arrays of tibial and femoral insertion sites. Larger graft sizes, antero-lateral tibial insertion site shift and anterior-proximal femoral insertion site shift increased impingement.