Assessment Of Cartilage Contact And Early Degeneration Following Acl Reconstruction

Download or read book Assessment of Cartilage Contact and Early Degeneration Following ACL Reconstruction written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: While ACL-reconstruction following injury restores knee stability and allows patients to return to activity, rates of early osteoarthritis post-surgery are high, with some reports as high as 80% of patients showing degeneration within 20 years. Many believe that early OA is due to residual abnormalities in joint mechanics after ACL-reconstruction. Proving a direct link between altered mechanics and cartilage degeneration, however, requires an imaging modality which can both measure in vivo joint motion with high accuracy and detect early degeneration. This thesis uses a new dynamic imaging sequence to measure in vivo joint motion and advanced quantitative MR sequences to assess cartilage composition to investigate potential links between cartilage loading and degeneration following ACL-reconstruction. We first validated the novel dynamic MR sequence, termed SPGR-VIPR, showing it is able to track tibiofemoral rotations and translations with precisions less than 0.8° and 0.5 mm, respectively. We then confirmed that healthy subjects exhibit bilateral symmetry in tibiofemoral kinematics during active knee flexion, which supports the use of the contralateral knee as a control in ACL-reconstructed knees. We then performed the dynamic imaging protocol on patients who previously had unilateral, primary ACL-reconstruction 1-3 years prior. We found that an inertial loading paradigm elicited significant asymmetries in knee kinematics, with the ACL-reconstructed knees exhibiting greater external tibial (~2°) and patellar (~1.3°) rotation during active flexion. These kinematic abnormalities lead to a shift in contact in both the medial and lateral tibial plateaus. The quantitative MR sequence, termed MC-DESPOT, also identified a significant decrease in proteoglycan-bound water metrics in both the medial and lateral tibial plateau, which may be indicative of early cartilage degeneration. We conclude that early biomarkers of osteoarthritis coincide with the time at which abnormal knee mechanics can be observed in ACL-reconstructed knees.