Background

Shoulder impingement syndrome is the most common disorder of the shoulder.

• Associated with subacromial bursitis, partial rotator cuff tears, rotator cuff tendinosis, and calcified tendonitis
• Incidence of shoulder pathology ranges from 7 to 25 per 1000 visits to primary care physicians
• Prevalence ranges from 7% to 27% in those less than 70 years of age and 13% to 26% in those older than 70 years of age
• Repetitive or excessive contact or abrasion of the rotator cuff muscles and/or tendons due to compression between the humeral head and acromion, coracoacromial ligament and acromioclavicular joint

Risk Factors

• Deconditioning
• Neurological injuries
• Sports involving throwing or overhead activities
• Trauma
• Poor ergonomics

Clinical Features

• Shoulder pain causes pain along the scapula and trapezius muscle but not the neck and is worsened with forward flexion of the shoulder and the pain is often referred to the lateral shoulder and mid arm. Patients note difficultly removing their shirt or coat
• Cervical pathology can radiate into the shoulder and shoulder pathology can radiate into the neck
• Cervical pathology may lead to secondary shoulder disease such as frozen shoulder
• Atrophy of the shoulder musculature can be associated with either C5 or C6 radiculopathy or chronic rotator cuff injury
• Active shoulder range of motion limitations may be related to deltoid or rotator cuff weakness resulting from a cervical radiculopathy or disuse atrophy caused by pain.
• Progresses from edema and hemorrhage to cuff fibrosis and thickening or a partial cuff tear and finally develop into full thickness tears, tendon ruptures and bony changes

Diagnosis

Differential diagnosis

• Cervical disc herniation with radiculopathy
• Cervical myelopathy
• Cervical spondylosis
• Frozen shoulder
• Glenohumeral instability or osteoarthritis
• Lung tumors
• Nerve palsies
• Shoulder impingement syndrome

Workup

• X-rays of the shoulder should include anterior-posterior, lateral and axillary views
• MRI is the study of choice for assessing for rotator cuff tears
• MRI may detect rotator cuff tears in 34% of asymptomatic individuals and this frequency increases with age
• CT is useful in diagnosing subtle dislocations, labral tears, full thickness rotator cuff tears, bony lesions, subtle dislocation
• Musculoskeletal ultrasonography
• Electrodiagnostic studies are usefully in differentiating shoulder pathology from radiculopathy and myopathy as well as determining the severity and chronicity of the neurological process

Treatment

• Rest
• Ice
• Nonsteroidal anti-inflammatory medications such as naprosyn or ibuprofen for < 2 weeks
• Acetaminophen
• Progressive strengthening exercises of the rotator cuff muscles
• Heat, cold, ultrasound, and transcutaneous electrical nerve stimulation have been used for symptomatic relief of pain and muscle spasms.
• Anesthetic injection into the subacromial region can help with diagnosis and treatment
• Intra-articular or subacromial corticosteroid and anesthetic injections have been shown to provide short-term relief
• Intra-articular sodium hyaluronates into the glenohumeral joint or bursa have been well tolerated
• Regenerative injections can be useful for tissue repair and long-term improvement
• Intra-articular injections should be done under imaging guidance
• Open acromioplasty and rotator cuff repair in 21 patients with electrodiagnostically documented cervical radiculopathy demonstrated decreased shoulder pain in 87% of patients and decreased neck pain in 66% of patients.

Prognosis

• Progression of a partial rotator cuff tear to a full tear with loss of shoulder function
• Mobility may be maintained even with evidence of a full rotator cuff tear

References

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.