Rotator cuff tendinitis

Rotator cuff tendinitis usually refers to inflammation of the supraspinatus tendon under the coracoacromial arch, however any of the tendons that make up the rotator cuff may be involved.

The condition usually follows prolonged or excessive use of the arm in an abducted position. It is more commonly a complaint of older people in whom there may be pre-existing impingement of the rotator cuff and in whom healing occurs more slowly. Vigorous or strenuous activity in younger people may produce a similar but more acute condition which usually resolves spontaneously upon rest.

Notes:

• over 90% of tendinopathies have no inflammation, thus the term tendinosis is more appropriate than tendinitis for most diagnoses (1)
• rotator cuff impingement syndrome
  • rotator cuff muscle tendons pass through a narrow space between the acromion process of the scapula and the head of the humerus
    • anything which causes further narrowing of this space can result in impingement syndrome
      • causes include
        • bony structures such as subacromial spurs (bony projections from the acromion), osteoarthritic spurs on the acromioclavicular joint, and variations in the shape of the acromion
        • thickening or calcification of the coracoacromial ligament
        • loss of function of the rotator cuff muscles, due to injury or loss of strength, may cause the humerus to move superiorly, and cause impingement
        • inflammation and subsequent thickening of the subacromial bursa
      • however within the rotator cuff, supraspinatus is the cuff tendon most liable to injury. It is the most exposed of the tendons - running over the top of the shoulder under the anterior edge of the acromion and the adjacent acromioclavicular joint - and also has a relatively poor arterial blood supply near to it's insertion into the greater tuberosity. Consequently, `supraspinatus' is often used synonymously with `rotator cuff' when describing lesions of this area
        
        
  • clinical features
    • pain, weakness and loss of motion are the most common symptoms reported
      • pain is exacerbated by overhead or above-the-shoulder activities
      • a frequent complaint is night pain, often disturbing sleep, particularly when the patient lies on the affected shoulder
    • onset of symptoms may be acute, following an injury, or insidious, particularly in older patients, where no specific injury occurs
    • there may be a grinding or popping sensation during movement of the shoulder
    • range of movement may be limited by pain
    • a painful arc of movement may be present during forward elevation of the arm from 60° to 120°
    • passive movement at the shoulder will appear painful when a downwards force is applied at the acromion but the pain will ease once the downwards force is removed
      
      
  • click here for a video of examination of the rotator cuff and possible impingement

Reference:

1. Br J Sports Med. 2009 Apr;43(4):259-64
2. Fongemie AE, Buss DD, Rolnick SJ. Management of shoulder impingement syndrome and rotator cuff tears.Am Fam Physician. 1998 Feb 15;57(4):667-74, 680-2.