Shoulder Impingement, Rotator Cuff Tendonitis and Subacromial Bursitis

Spectrum of the same condition

Aetiology

  • Impingement occurs most commonly in patients under 25 years, typically in active/athletic individuals or in manual professions
  • Impingement can occur in the older population secondary to degenerative changes or acromioclavicular bony changes

Pathophysiology

Shoulder impingement

  • Refers to the inflammation and irritation of the rotator cuff tendons as they pass through the subacromial space, resulting in pain, weakness, and reduced range of motion within the shoulder
Intrinsic mechanisms
  • Muscular weakness - weakness in rotator cuff muscles can lead to the humerus shifting proximally towards the body
  • Overuse of the shoulder - repetitive microtrauma can result in soft tissue inflammation of the rotator cuff tendons and the subacromial bursa
  • Degenerative tendinopathy - degenerative changes of the acromion can lead to tearing of the rotator cuff, which allows for proximal migration of the humeral head
Extrinsic mechanisms
  • Anatomical factors - congenital or acquired anatomical variations in the shape and gradient of the acromion
  • Scapular musculature - a reduction in function of the scapular muscles may result in a reduction in the size of the subacromial space
  • Glenohumeral instability - can lead to superior subluxation of the humerus, causing an increased contact between the acromion and subacromial tissues

Rotator cuff tendonitis

  • Repeated impingement results in inflammation or damage of the rotator cuff tendons

Subacromial bursitis

  • In more severe cases of rotator cuff tendonitis, there may be calcification of the tendon, and associated subacromial bursitis → subacromial bursa also becomes inflamed
  • This can then exaggerate the problem, as the now inflamed tendons rub against the acromium, and clavicoaromial joint and ligament

Neer's Classification

  1. Inflammation, oedema and haemorrhage (<25 years)
  1. Fibrosis and tendonitis bursa/cuff (25-40 years)
  1. Partial/full thickness tears and degeneration of rotator cuff (>40 years)

Clinical presentation

Symptoms

  • Progressive pain in the anterior superior shoulder
  • Pain characteristically radiates to the deltoid and upper arm
  • Difficulty sleeping on affected side, reaching overhead and lifting
  • Pain exacerbated by abduction and relieved by rest

Signs

  • Tenderness below the lateral edge of the acromion
  • Tests: Hawkins-Kennedy, Jobe's, painful arc

Investigations

  • X-ray - AP shoulder and Garth views (apical oblique) or outlet view
    • Generally normal
    • May show a bone spur
    • Rules out AC joint arthritis
  • USS or MRI depending on shoulder mobility

Management

Conservative

  • Rest, activity modification
  • Analgesia, NSAIDs
  • Physiotherapy
  • Corticosteriod injections in subacromial space up to 2x
    • Particularly if there is associated subacromial bursitis
  • Resolves in most cases

Surgery

  • Subacromial decompression should only be considered after a minimum of 6 months non-operative management
  • Other surgical options (cause dependent):
    • Subacromial/subdeltoid bursectomy
    • Release of CA ligaments
    • Release of calcific deposits
    • Exision infraclavicular spur