What is shoulder instability?

Shoulder instability corresponds to episodes of dislocations or subluxations, often after initial trauma or in hyperlaxity context. This pathology can become chronic with apprehension, pain and significant functional discomfort.

The shoulder is the most mobile joint in the human body, making it particularly vulnerable to instabilities. Management depends on instability type, patient age and functional expectations.

Types of instability

Anterior instability

The most frequent, corresponds to forward dislocation of the humeral head. Often related to trauma with Bankart lesion.

Posterior instability

Rarer, corresponds to backward dislocation. Often related to electrical trauma or epileptic seizures.

Multidirectional instability

Instability in several directions, often related to constitutional hyperlaxity or repeated microtrauma.

Mechanisms and causes

Traumatic instability

Initial dislocation after trauma with Bankart lesion (glenoid labrum detachment). Recurrences are frequent in young and athletic subjects.

Associated lesions: Glenoid bone loss, Hill-Sachs notch on humeral head.

Atraumatic instability

Instability related to constitutional or acquired hyperlaxity, often bilateral. Repeated microtrauma may worsen instability.

Favoring factors: Constitutional hyperlaxity, throwing sports, repetitive work above the head.

Symptoms and manifestations

Pain and apprehension

Chronic shoulder pain, apprehension sensation during elevation and external rotation movements. Patient avoids certain movements for fear of dislocation.

Characteristics: Often diffuse pain, aggravated by sports or professional activities.

Dislocation sensations

Sensations of dislocation or subluxation during elevation and rotation movements. Patient may sometimes reduce subluxation himself.

Functional impact: Limitation of sports and professional activities, loss of confidence in the shoulder.

Diagnosis and evaluation

Clinical examination

• Instability tests: Apprehension test, relocation test, sulcus test
• Laxity assessment: Anterior and posterior translation tests
• Neurological examination: Search for associated nerve lesions
• Functional assessment: Impact on daily and sports activities

Imaging examinations

X-rays

Basic examination to assess humeral head position and look for bone lesions

MRI

Reference examination to assess soft tissue lesions and glenoid labrum

Arthro-CT

Specialized examination to precisely assess labrum lesions and plan surgical treatment

Therapeutic options

Conservative treatment

Conservative treatment is preferred as first intention, particularly for atraumatic instabilities and elderly patients.

• Rehabilitation: Strengthening of shoulder stabilizing muscles
• Education: Avoid risky positions, protection techniques
• Injections: Corticosteroid injection in case of significant pain
• Activity modification: Sport or work adaptation

Surgical treatment

Surgery is indicated for recurrent traumatic instabilities and atraumatic instabilities resistant to conservative treatment.

Surgical indications:

• Recurrence of dislocations in young/athletic subjects
• Persistent apprehension despite well-conducted rehabilitation
• Significant glenoid bone loss or engaging Hill-Sachs lesion

Arthroscopic Bankart

Arthroscopic repair of glenoid labrum for capsulo-labral lesions without significant bone loss.

Coracoid buttress (Latarjet)

Transfer of coracoid to glenoid for significant bone losses or recurrences after Bankart.

Capsulorrhaphy

Narrowing of articular capsule for multidirectional instabilities.

Post-operative rehabilitation

Rehabilitation after shoulder instability surgery is crucial to optimize functional recovery and prevent recurrences.

Phase 1: Immobilization (2-3 weeks)

Sling according to procedure performed, early passive mobilizations to maintain mobility

Phase 2: Active mobilization (3-6 weeks)

Progressive active mobilizations, beginning of stabilizing muscle strengthening

Phase 3: Strengthening (6 weeks - 6 months)

Progressive strengthening, return to sports activities according to protocol

Return times: Return to contact/throwing sports: 3-6 months according to protocol and evolution.

Possible complications