Shoulder Instability

Shoulder instability can be defined as excessive translation of the humeral head on the glenoid fossa.

The gleno-humeral joint is the most commonly dislocated joint with an incidence of 8.2 to 23.9 per 100,000 per year. 96% of shoulder dislocations can be attributed to a traumatic episode with anterior dislocations accounting for 97% of these. 50% occur in patients between the age of 15 and 29 years with a second peak in females over the age of 80 years. The risk of recurrent dislocation is inversely proportional with the patient's age, with males under 20 years having approximately 72% chance of recurrent instability. However, the incidence of post-dislocation rotator cuff tears increases with age, with one study identifying an incidence of 100% in patients over 70 years, though not all of these are symptomatic.

Traumatic posterior dislocation are rare (3% of traumatic dislocations) but should be considered in patients with shoulder pain post-epileptic seizures or electrocution (require AP glenohumeral joint and axillary view xrays to diagnose/exclude).

Instability may also be atraumatic or due to muscle patterning, conditions in which patients usually have minimal or no history of trauma, are able to self-relocate, and are most commonly posterior dislocations.

Key Messages

Community based treatments including analgesia, landmark guided injection and physiotherapy are the mainstay of treatment for most shoulder conditions


Adults with shoulder instability

Out of scope

Patients without shoulder instability


  • Patients with instability often complain of a feeling that their shoulder might move out of place.

Red Flags

  • Combination of Trauma, Pain and Weakness should raise suspicion of Acute Cuff Tear
  • Mass or swelling should raise suspicion of tumour
  • Erythema, Fever should raise suspicion of infection
  • Unexplained wasting, significant sensory or motor deficit
  • Acute onset of pain and severe tenderness over the cuff


Acute unreduced dislocations should be sent to the local ED department for reduction.

Atraumatic dislocations (usually patients under the age of 13 years) should be referred to the Specialist Shoulder Physio clinic at Torbay Hospital for a detailed assessment and treatment. If significant progress has not been achieved within six months, the Specialist Shoulder Physios will refer these patients onto the shoulder clinic for further assessment.


Referral Instructions

Refer to Orthopaedics e-Referrals Service Selection

  • Speciality: Orthopaedics
  • Clinic type: Shoulder
  • Service: DRSS-South Devon & Torbay-Orthopaedics-Shoulder & Elbow- Devon CCG - 15N

Referral Forms

Shoulder condition - PCT Referral form

DRSS referral form

Supporting Information

Pathway Group

This guideline has been signed off by South Devon and Torbay CCG

Publication date: December 2017


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