Shoulder and Elbow research interests and activities include both basic science and clinical topics. Molecular biologic investigations include the pathophysiology of rotator cuff disease, mechanisms of healing and repair in shoulder instability, and augmentation of healing using growth factors and platelet rich plasma. Biomechanical research studies involve strength of biceps tenodesis and animal models of shoulder instability. Clinical topics include glenohumeral arthritis and shoulder replacement, injections for tennis elbow, and outcomes of rotator cuff repair.
Another line of research involves the pathophysiology of shoulder instability. Although the anatomic pathology of this injury has been described by Blundell Bankart in 1923, no further investigations have been performed to explain why this tear in the glenoid labrum does not heal. We have recently developed a new model for shoulder instability by creating a labral injury and assessing the healing potential using both biomechanical and immunohistochemical techniques. These initial studies have been presented at the American Academy of Orthopaedic Surgeons Meeting this year and further studies are in progress. The ultimate goal of these investigations are to determine which factors are important for labral healing. With this information, we may be able to devise pharmacologic agents to augment labral healing that may obviate the need for surgical reconstruction in patients with shoulder instability.
Rotator cuff disease is one of the most common musculoskeletal problems. However, the molecular pathophysiology of rotator cuff disease is still unclear. With grant support from an NIH COBRE grant and with funds from both the OREF and ASES, we have studied the role of the subacromial bursa in the pathology of rotator cuff disease. We were the first to characterize stromal derived factor-1 (SDF-1) in human subacromial bursa tissue, and quantified SDF-1 mRNA and protein levels in subacromial bursa. With these studies, we also found that commonly used pharmacologic agents (non steroidal anti-inflammatory drugs and corticosteroids) reduced the expression of SDF-1 in subacromial bursal cells. These results provided biologic evidence for the use of NSAIDs and steroids in the treatment of subacromial bursitis and rotator cuff disease.
Due to the deleterious side effects of NSAIDs and steroids on rotator cuff healing, subsequent studies have focused on the identification of new anti-inflammatory agents to treat subacromial inflammation. Using an in vitro model of subacromial inflammation, we have discovered that SDF-1 receptor (CXCR4) inhibitors may have a role in the treatment of subacromial bursitis. Recent studies have used animal models to test the ability of these agents to reduce inflammation without affecting rotator cuff healing. These investigations are still in progress.