Shoulder instability
The shoulder is the most mobile joint in the human body, capable of movement in all directions. This remarkable range of motion is explained by its unique anatomical structure: a suspended joint where a sphere (the head of the humerus) articulates with a shallow concave surface (the glenoid cavity of the scapula). This configuration, comparable to a ball resting on a golf tee, favors mobility at the expense of natural stability. Shoulder instability manifests as a sensation of dislocation or partial dislocation during certain movements, thus compromising the normal function of this joint, which is essential to our daily activities.
Causes
Shoulder instability results primarily from two distinct mechanisms. Traumatic instability follows an accident, usually a sudden dislocation that damages the stabilizing structures (joint capsule, glenoid labrum, ligaments). This form usually affects only one side and particularly concerns young athletes practicing activities with a risk of falling or contact. Atraumatic instability, which is rarer, is observed in people with constitutional hyperlaxity. In this case, the joint structures are naturally more flexible, predisposing to episodes of instability without prior trauma. Both shoulders are generally affected, and this instability can manifest itself during simple activities such as combing hair or sleeping.
Symptoms
Symptoms vary depending on the type and severity of instability. In an acute traumatic dislocation, the pain is intense and accompanied by a complete inability to use the arm. This medical emergency requires immediate reduction by a healthcare professional. In chronic forms, the most characteristic symptom is dislocation apprehension: a feeling of instability that occurs in certain positions, particularly when the arm is raised and rotated outward. This apprehension may be accompanied by dull pain, limited movement, and sometimes episodes of subluxation (partial dislocation), which the patient often learns to reduce on their own.
Treatments
Treatment of shoulder instability depends on its origin and severity. In atraumatic forms related to hyperlaxity, the approach is essentially conservative: physiotherapy targeted at strengthening the shoulder stabilizing muscles (particularly the rotator cuff), proprioception exercises to improve neuromuscular control, and learning joint-protective movements. Anti-inflammatory drugs can temporarily relieve pain. If conservative treatment fails or when instability significantly impedes activities, corticosteroid injections may be offered to reduce local inflammation and improve comfort.
Surgery
Surgical intervention is particularly recommended in traumatic instabilities, especially in young patients where the risk of recurrence reaches 90 to 95% before the age of 20. The Bankart operation, the reference technique, consists of repairing and tightening the joint capsule as well as reattaching the glenoid labrum when it is detached. This intervention can be performed arthroscopically (a minimally invasive technique preferred for faster recovery) or openly depending on the complexity of the lesions. In certain specific cases of multidirectional instability, global capsular retensioning may be necessary. Surgical success depends largely on compliance with the postoperative rehabilitation protocol, which includes six weeks of relative immobilization followed by progressive physiotherapy to recover mobility, strength and stability.
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This article is original and was created entirely by our team of referring physicians. Last updated September 17, 2025.
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- Specialist in orthopedic surgery and traumatology. Shoulder surgery
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