Rotator Cuff Tendinopathy

Introduction and prevalence

Rotator Cuff Tendinopathy (RCT) refers to a range of diseases in the domains of inflammation, degeneration, and injury that affect the rotator cuff muscles. These conditions include subacromial impingement syndrome, bursitis, rotator cuff tendonitis, and rotator cuff tears. Shoulder pain is the third-leading MSK complaint at primary care, with the prevalence of RCT ranging from 10% in patients younger than 20 years old, to over 60% in patients aged 80 or older.

Etiology and Pathophysiology

The rotator cuff muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis, that help stabilize the shoulders. Inflammation, injury, or degenerative changes affecting these muscles and the associated tendons can lead to RCT. RCT can be associated with rotator cuff tendonitis and shoulder impingement. The causes of RCT are usually repetitive injury to the cuff and can be divided into extrinsic compression, such as degenerative bursa and acromial spurring, and intrinsic compression, such as from movements experienced by overhead-throwing athletes (baseball pitchers, javelin throwers, etc.). These changes to the cuff eventually undermine the overall stability of the glenohumeral joint, causing the humeral head to migrate superiorly, reducing the size of the subacromial space.

Clinical presentation

Shoulder pain secondary to RCT is usually atraumatic with insidious onset of pain, symptoms exacerbated with overhead activity, and shoulder pain at night.

Physical examination

Cervical radiculopathy should be ruled out. After a full visual and physical examination of the shoulders, including ROM assessments, the clinicians can utilize special tests to assess for RCT.

  • Jobe’s test is when the patient's shoulder is positioned at 90° of forward flexion and abduction in the scapular plane with the thumbs pointing down; pain or weakness with resisted downward pressure is suggestive of supraspinatus compromise.

  • Infraspinatus function can be assessed by resistance again external rotation of the shoulder.

  • Teres minor can be assessed by Hornblower’s test, where the affected arm is abducted at 90° in the scapular plane and the elbow flexed at 90°, and the patient externally rotates the arm against resistance.

  • Subscapularis function can be assessed through the lift-off test, where the patient holds his arm behind him with the elbow at 90° and tries push way from the body against resistance.

  • Other tests include Neer’s impingement test, where the clinician flexes the patient’s straight, internally rotated arm above their head, with pain indicative of a positive result.

  • Hawkin’s test is another test for impingement where the clinician passively internally rotates the patient’s arm that is at 90° flexion both at the shoulder and elbow in front of the body, with pain indicative of a positive result.

Investigations

The recommended imaging includes AP view and a 30° caudal tilt view of the glenohumeral joint. US can be helpful for superficial rotator cuff tears, with sensitivity of 96% and specificity of 93%. MRI is used for evaluation of deeper tears, along with fatty degenerative changes.

Management

First-line treatment options include physical therapy, particularly periscapular stabilizer strengthening programs and ROM exercises, and NSAIDs. These are particularly helpful for incomplete rotator cuff tears and rotator cuff tendonitis. Cortisone injections into the subacromial space has been shown to be beneficial for symptoms management of rotator cuff tendonitis. Activity modifications include stopping repetitive overhead activity and heavy lifting. Surgical interventions, including subacromial decompression, acromioplasty, and Os Acromiale, are reserved for patients that don’t respond to conservative therapy or have full-thickness rotator cuff tears.