SC joint instability

Sternoclavicular joint instability: causes, symptoms, and treatment

Sternoclavicular joint (SCJ) instability is a rare but significant condition that can be triggered by both acute injuries and chronic processes. The SCJ represents the only bony connection between the shoulder girdle and the rib cage and plays a key role in the stability and mobility of the entire shoulder apparatus. Its stability is largely ensured by strong ligaments, the joint capsule, and the articular disc. Instability of the SCJ can lead to excessive mobility or even complete dislocation of the joint, which is not only painful but can also significantly impair the function of the shoulder girdle.

Instability of the SCJ often occurs after trauma, for example, a direct impact to the shoulder or a fall. In such cases, stabilizing structures such as the ligaments or the joint capsule can tear, leading to dislocation of the joint. A distinction is made between an anterior dislocation, in which the clavicle slips forward out of the joint socket, and a posterior dislocation, in which it is displaced backward. The latter is particularly dangerous because important structures such as the trachea, major blood vessels, or esophagus are located in close proximity and can be injured. In addition to traumatic causes, degenerative processes such as osteoarthritis or inflammatory diseases, such as rheumatoid arthritis, can also contribute to instability. In some cases, the instability is congenital or caused by general joint laxity, as occurs in connective tissue diseases.

The symptoms of SCJ instability vary depending on the severity of the condition. Typical symptoms include pain, which often occurs with movements of the shoulder girdle or when pressure is applied to the joint. Patients frequently report a feeling of insecurity or instability in the joint, which is particularly noticeable during stress or certain movements. Dislocations can result in visible deformities, such as protrusion of the clavicle in an anterior dislocation. Swelling, redness, and restricted movement are also common. Posterior dislocation can also be accompanied by shortness of breath, difficulty swallowing, or neurological deficits due to the pressure it places on adjacent structures.

The diagnosis of SCJ instability is usually made through a combination of medical history, clinical examination, and imaging. The physician will assess the stability of the joint, the mobility of the shoulder girdle, and look for signs of pain or deformity. X-rays are helpful in detecting dislocations or bony changes. If a posterior dislocation or complex joint injury is suspected, a computed tomography (CT) scan is often performed, as it provides a detailed view of the bony and surrounding soft tissue structures.

Treatment for SCJ instability depends on the cause and severity of the condition. In acute dislocations, closed reduction can often be performed, which returns the joint to its normal position without surgery. The joint is then immobilized with a sling or brace for several weeks to allow the ligaments to heal. Physiotherapy plays a key role in rehabilitation to strengthen muscles and restore mobility. Chronic instabilities that do not respond to conservative measures or cases with persistent symptoms may require surgical treatment. Various procedures are used, such as ligament reconstruction, joint fixation, or, in severe cases, resection of the medial end of the clavicle. Posterior dislocations that cannot be stabilized often require surgical stabilization to avoid life-threatening complications.

Overall, the prognosis of SCJ instability depends on the cause and the chosen treatment. With early diagnosis and appropriate treatment, most patients can regain their functionality and quality of life. Rapid intervention is particularly crucial in traumatic dislocations to prevent subsequent complications. SCJ instability may be rare, but its impact on shoulder girdle function and the quality of life of those affected makes careful diagnosis and treatment essential.