Subacromial Impingement Syndrome

Key Features

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

• Causes of impingement syndrome can be related to

  • Muscle strength imbalances

  • Poor scapula control

  • Rotator cuff tears

  • Subacromial bursitis

  • Bone spurs

Clinical Findings

• Pain, instability, weakness, or loss of range of motion

• 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)

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

• Atrophy in the supraspinatus or infraspinatus fossa may be appreciable

• Mild scapula winging or "dyskinesis" may be present

• Patient often has a rolled-forward shoulder posture or head-forward posture

• Tenderness over the anterolateral shoulder at the edge of the greater tuberosity may be present

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

Diagnosis

• Four radiographic views should be ordered

  • Anteroposterior scapula view can rule out glenohumeral joint arthritis

  • Anteroposterior acromioclavicular view evaluates the acromioclavicular joint for inferior spurs.

  • Scapula Y view evaluates the acromial shape

  • Axillary lateral view 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

• Ultrasound evaluation may demonstrate thickening of the rotator cuff tendons and tendinosis

Treatment

• Most patients respond well to conservative treatment, including education, activity modification, and physical therapy exercises

• Procedures include arthroscopic acromioplasty with coracoacromial ligament release, bursectomy, or debridement or repair of rotator cuff tears