Shoulder impingement syndrome is the most common disorder of the shoulder. It is often associated with subacromial bursitis, shoulder rotator cuff tear, shoulder tendinitis or tendinosis, and calcified tendonitis. The incidence of shoulder pathology makes up 2.5% of visits to primary care physician, and the prevalence within the U.S. is greater than 25%. Risk factors include deconditioning, neurological injuries, sports involving throwing or overhead activities and trauma.
The shoulder is an amazing structure allowing you to move in many directions. When the intricate muscle balance is disrupted due to repetitive or excessive contact or abrasion of the rotator cuff muscles and tendons the tissues get overloaded causing wear-in-tear. After a while when enough tissue has broken down, you develop shoulder pain eventually resulting in weakness and stiffness. Pathology progresses from edema and hemorrhage to cuff fibrosis and thickening or a partial cuff tear that develops to full thickness tears, tendon ruptures and bony changes.
The symptoms can vary in intensity and frequency. They include:
• Pain along the scapula and is worsened with forward flexion of the shoulder. The pain is often referred to the lateral shoulder and mid arm.
• Difficulty removing your shirt or coat and reaching overhead.
• Atrophy of the shoulder muscles
• Active shoulder range of motion limitations may be related to deltoid or rotator cuff weakness resulting from pain-related disuse atrophy
Other causes of shoulder pain include:
• Cervical disc herniations
• Cervical myelopathy of the spinal cord• Cervical spondylosis (arthritis)
• Frozen shoulder
• Glenohumeral instability or osteoarthritis
• Lung tumors
• Nerve damage
Often only simple treatments such as a modification of activity, anti-inflammatory medications, rotator cuff strengthening and physical therapy are all that are needed. If minimal progress is noted, then an anesthetic injection into the region of interest in the shoulder can help with diagnosis and treatment. Intra-articular or subacromial corticosteroid and anesthetic injections using ultrasound guidance have been shown to provide short-term relief. Alternately, intra-articular sodium hyaluronate into the glenohumeral joint or bursa using ultrasound guidance have been well tolerated as well without the side effects of steroids. In patients that have not had significant improvement then more advanced procedures are done which include a platelet-rich plasma (PRP) injection to regenerate the damaged tissue.
Hawkins RJ, Bilco T, Bonutti P. Cervical spine and shoulder pain. Clin Orthop Relat Res. 1990 Sep;(258):142-6.
Panagos A. Rehabilitation Medicine Quick Reference-Spine (ed. Buschbacher R.M.) New York: Demos Publishing; 2010. p. 200-201.