The Effect of Geographic Bone Bruises on Biological Markers and MRI Findings of Osteoarthritis After Anterior Cruciate Ligament Injury (funded by Nfl Charities)
Clinical evidence and epidemiological investigations show that anterior cruciate ligament (ACL) injury increases the risk for progressive joint degeneration, ultimately resulting in post-traumatic osteoarthritis (OA). Although clinicians and scientists are aware that ACL injury leads to degenerative joint disease, very little is known about its onset following the initial trauma and the mechanisms responsible for the loss of normal articular cartilage. Often by the time post-traumatic OA is diagnosed, excruciating pain and irreversible damage to joint surfaces has taken place leaving patients with few options to maintain quality of life. Subchondral bone injuries (“bone bruises”) accompany 80% of ACL ruptures and are thought to be the hallmark of subsequent osteoarthritis. These injuries may result in acute changes to overlying articular cartilage and subsequent degradation of both bone and cartilage. The role that subchondral bone contusions play in the development of post-traumatic osteoarthritis remains elusive and needs to be addressed so that preventive measures can be implemented. The proposed investigation will use a prospective study design with a relatively homogenous group of subjects who have sustained an acute ACL rupture and are scheduled to undergo reconstructive surgery. We plan to measure the serum concentration of selected biomarkers suggestive of inflammation and cartilage matrix turnover. Further, we will also examine magnetic resonance (MR) images using a validated pulse sequence and quantitative T2 mapping to prospectively assess changes in cartilage morphology as well as alterations in extracellular matrix components. These measurements will be made both in patients with an ACL rupture and a geographic bone bruise as well as in teammate and acquaintance control subjects with normal knees. Measurements will be gathered upon enrollment and at 12 months post-reconstruction. These data will be used to test our hypotheses that biomarkers of articular cartilage degradation are elevated in those with subchondral bone lesions and that bone bruises result in cartilage injury and loss of matrix integrity, as detected by MRI.