Overview of subacromial pain syndrome

Figure 1. Key practice points for subacromial pain syndrome.

[NB1]

  • Subacromial pain syndrome is most commonly associated with tendinopathy.
  • One-third of people will have ongoing symptoms after 1 yearDiercks, 2014).
  • Diagnosis is clinical and investigations are usually not required.
  • Treatment is symptomatic with oral analgesia, avoidance of aggravating activities, support for the person’s mental health and, in the case of tendinopathy, a gradual reintroduction to exercise (including a progressive-loading program).
  • Local corticosteroid injection can be used if symptoms are persistent (eg beyond 6 weeks).
Note: NB1: This list is a summary guide only; refer to full text.
Subacromial pain syndrome (of which rotator-cuff disease is a component) comprises all nontraumatic, usually unilateral, shoulder-pain disorders localised around the acromion process of the scapula. The pain often worsens during or after lifting the arm. Key practice points for subacromial pain syndrome lists some key practice points for subacromial pain syndrome.

Subacromial pain syndrome includes various pathologies of the shoulder tendons, including:

  • tendinopathy involving the rotator-cuff tendons—most commonly affecting the supraspinatus tendon
  • tendinopathy involving the long head of biceps tendon
  • microtear(s) or partial tear(s) of these tendon(s)
  • bursitis around the shoulder joint (eg subacromial bursitis)
  • impingement syndrome—mechanical impingement of rotator-cuff tendons and associated structures below the acromion, (eg osteoarthritis (OA) with osteophytes).

Complete tendon tears, calcific tendinitis and adhesive capsulitis are associated with pain in the subacromial region, but they are not usually defined as components of subacromial pain syndrome. Adhesive capsulitis is covered in a separate topic.

The rotator cuff comprises the supraspinatus, infraspinatus, subscapularis and teres minor muscles and tendons; these muscles and tendons surround the glenohumeral joint, facilitate movement and provide stability to the joint.

The aetiology of subacromial pain syndrome is multifactorial. Risk factors for its development include:

  • abnormal acromial (bony) morphology (eg acromioclavicular joint OA that narrows the subacromial space)
  • scapular dysfunction (eg malpositioning of the glenoid fossa)
  • increasing age
  • overuse
  • tobacco smoking
  • obesity.

Symptomatic subacromial pain syndrome is common in young people who participate in sports involving overhead activity (eg tendinopathy associated with overuse in swimming).

Symptomatic subacromial pain syndrome is also common in middle-aged and older people, who are more likely to sustain partial or complete rotator-cuff tears however, these tears are usually traumatic and are not typically defined as components of subacromial pain syndrome.

Asymptomatic micro- and partial tears of the rotator-cuff tendons are present in 4% of people under 40 years, and in more than 40% of people over 60 years.

The natural history of untreated subacromial pain syndrome is not well understood. About 25% of new episodes resolve fully within 1 month and nearly 50% resolve within 3 months; however, symptoms can persist or symptoms can recur within a year of initial presentation. A 2019 review1 reported 23 to 51% of asymptomatic rotator-cuff tears could become symptomatic within 18 to 36 monthsLawrence, 2019.

Many partial rotator-cuff tears progress to complete tears over time. Progression of rotator-cuff tears can lead to rotator-cuff arthropathy, a form of glenohumeral OA.

1 Lawrence RL, Moutzouros V, Bey MJ. Asymptomatic Rotator Cuff Tears. JBJS Rev 2019;7(6):e9. [URL]Return