Researchers warn against stem cell treatments for shoulder, elbow injuries

The utilization of stem cell therapies for augmentation of tissue healing has far outpaced the supporting scientific and clinical data, according to two reviews in the Journal of Shoulder and Elbow Surgery.

Researchers examined the current status of biologic approaches for common shoulder and elbow problems. The authors discuss areas where the current evidence base is weak or controversial and recommend where further studies are required.

There is significant interest in biologic treatment options to improve healing and reduce symptoms more rapidly in elbow and shoulder injuries, such as osteoarthritis, tendinopathy, ligament injuries, and other inflammatory conditions. However, there is uncertainty among physicians and patients about what works and what does not since many of these treatments are still unproven. While the authors caution that the outlook is positive, the clinical data for their use are currently limited.

Additionally, many patient-specific factors affect the composition and biologic activity of products, including age, sex, medical comorbidities, concomitant medications, and genetic and epigenetic factors. These variables as well as unpredictability of the ''biologic product'' are then added to the variability of the underlying pathology being treated, the authors said.

The authors review several biologic agents, including platelet-rich plasma, bone marrow aspirate concentrate, and mesenchymal stromal cells derived from adipose tissues, to provide medical specialists and their patients with up-to-date clinical data and stimulate further research in this important and growing area of musculoskeletal medicine. They conclude that these treatments have great potential based on laboratory studies demonstrating a positive effect of these materials on the basic biology of tissue healing, however, the clinical data for their use in both shoulder and elbow pathologies are very limited. The authors point out a that serious limitation is the significant variability and heterogeneity among these biologic formulations.

In a review of biologics for managing shoulder pathology, James Carr, MD, and Scott Rodeo, MD, both of the Sports Medicine Institute Hospital for Special Surgery in New York, evaluate the basic science and clinical evidence for the most commonly used biologic agents for treating common shoulder pathologies such as rotator cuff tears, shoulder osteoarthritis, and tendinopathy. Rotator cuff tears occur in more than 20 percent of the general adult population, with a progressively higher incidence as age increases, while shoulder osteoarthritis has been estimated to affect up to 33 percent of individuals over 60, the authors said.

Although the outlook may be positive, the authors call for further laboratory and clinical research to define optimal formulations, dosing schedules, and approaches for various tissues and injuries. As the safety and efficacy of these approaches are further defined, changes in the regulatory environment at the U.S. Food and Drug Administation level may also aid progress.

Tennis elbow, lateral epicondylitis, affects one to three percent of adults each year. At the elbow, this is the most common indication for biologic therapy and it is often compared to steroid injections. A detailed review by Jason Dragoo, MD, of the Department of Orthopedic Surgery at the University of Colorado in Denver and Molly Meadows, MD, of Stanford University in Redwood City, California identified studies on the use of biologics to treat elbow pathology. They found significant research on the use of platelet-rich plasma for lateral epicondylitis, but few studies on golfer's elbow or medial epicondylitis, ulnar collateral ligament injuries, and biceps tendinopathy. They also found studies using mesenchymal stromal cell-containing therapy in the treatment of lateral epicondylitis, but studies using mesenchymal stromal cells in other areas of elbow pathology were generally lacking.

The authors conclude that despite fairly widespread use of biologic agents such as platelet-rich plasma in lateral epicondylitis, further research is needed to determine the optimal formulation and administration of PRP injections. Additional rigorous studies are necessary to provide definitive data. Current research on the use of cell therapy in other elbow injuries is limited and further research on biologic therapy for golfer's elbow, ulnar collateral ligament injuries, and biceps tendinitis is needed.