Subacromial Impingement Syndrome

Key Features

Essentials of Diagnosis

• Shoulder pain with overhead motion

• Night pain with sleeping on shoulder

• Numbness and pain radiation below the elbow are usually due to cervical spine disease

General Considerations

• A collection of diagnoses that cause mechanical inflammation in the subacromial space

• Causes can be related to

  • Muscle strength imbalances

  • Poor scapula control

  • Rotator cuff tears

  • Subacromial bursitis

  • Bone spurs

• Because shoulder injuries may present differently depending on the demands placed on the shoulder joint, establishing the patient's hand dominance, occupation, and recreational activities is important

Clinical Findings

• Classically presents with one or more of the following:

  • Pain with overhead activities

  • Nocturnal pain with sleeping on the shoulder

  • Pain on internal rotation (eg, putting on a jacket or bra)

• On inspection, there may be appreciable atrophy in the supraspinatus or infraspinatus fossa

• Mild scapula winging or "dyskinesis" may be present

• A rolled-forward shoulder posture or head-forward posture is commonly seen

• On palpation, the patient can have tenderness over the anterolateral shoulder at the edge of the greater tuberosity

• The patient may lack full active range of motion (Table 41–1) but should have preserved passive range of motion

• Symptoms can be elicited with the Neer and Hawkins signs (Table 41–1)

Diagnosis

• The following four radiographic views should be ordered to evaluate subacromial impingement syndrome:

  • Anteroposterior (AP) scapula: can rule out glenohumeral joint arthritis

  • acromioclavicular joint: evaluates the acromioclavicular joint for inferior spurs

  • Lateral scapula (scapular Y): evaluates the acromial shape

  • Axillary lateral: visualizes the glenohumeral joint as well and for the presence of os acromiale

• MRI of the shoulder may demonstrate full- or partial-thickness tears or tendinosis

• Ultrasonography

  • May demonstrate thickening of the rotator cuff tendons and tendinosis

  • Tears may also be visualized, although MRI is preferred to identify partial tears and small full-thickness tears

Treatment

Conservative

• Education, activity modification, and physical therapy exercises

  • Rotator cuff muscle strengthening can alleviate weakness or pain, unless the tendons are seriously compromised, in which case exercises may cause more symptoms

  • Physical therapy is directed at rotator cuff muscle strengthening, scapula stabilization, and postural exercises

• There is no strong evidence supporting the effectiveness of ice and NSAIDs as a prolonged therapy

• In a Cochrane review, corticosteroid injections produced slightly better relief of symptoms in the short term when compared with placebo

Surgical

• Procedures include

  • Arthroscopic acromioplasty with coracoacromial ligament release

  • Bursectomy

  • Debridement or repair of rotator cuff tears

• However, the value of acromioplasty alone for rotator cuff problems is not supported by evidence

Outcome

Prognosis