Comparison of Injection Therapies for Acromioclavicular Joint Pain: A Randomized Clinical Trial

Shoulder pain is in the top five reasons related to musculoskeletal disorders that care is sought within the Military Health System. While acromioclavicular joint (ACJ) disorders, a subset of all shoulder pain disorders, are a high-volume condition seen in primary clinics, very little is known about the epidemiology in the military. At the United States Military Academy in West Point, 162 new cases were identified over a four-year period, which equaled an incidence rate of 9.2 per 1000 person-years. 

Onset of pain in athletes is most commonly related to activities which strain the ACJ, to include push-ups, military press, overhead press, as well as any forceful contact to the shoulder which provides a shear on the ACJ (falling on outstretched hand, direct blow to the elbow, landing forcefully on the side of the shoulder). These are all very common activities and often part of the daily routine for service members, as part of their physical and readiness training. Consequently, pain and inability to absorb normal stress in this joint after injury creates tremendous disability and greatly limits service members from being able to complete many of their daily duties. Ultimately, this affects military readiness substantially. Recovery is often slow and depends on the severity of the injury, but usually taking a minimum of six weeks and in many cases with recalcitrant symptoms lasting out to a year or more. Interventions that can speed up recovery and maximize pain-free function on return to duty are in high demand for service members, as they have the potential to directly impact the state of medical readiness for our service members.

Platelet-Rich Plasma (PRP) is a new treatment that shows promise for treating musculoskeletal disorders. The driving therapeutic mechanism is to leverage the restorative biological mechanisms in red blood cells using the patient’s own red blood cells to accelerate and promote healing. PRP is currently utilized in the clinic, but its cost can be prohibitive. Corticosteroid injections may be as clinically effective as PRP for managing acromioclavicular pain, but at a fraction of the price. This study aims to assess whether corticosteroid injections are non-inferior to PRP.