What does it mean if the acromioclavicular joint space is widened by 6 mm, and what should I do?

Generally, an acromioclavicular joint space widening of 6mm may be caused by congenital acromioclavicular joint dysplasia, acromioclavicular arthritis, adhesive capsulitis (frozen shoulder), acromioclavicular joint dislocation, clavicle fracture, and other reasons. Management depends on the specific condition.

1. Congenital acromioclavicular joint dysplasia: During embryonic development, genetic or environmental factors may lead to abnormal development of the bones and cartilage of the acromioclavicular joint. This results in widening of the clavicular space at birth. Generally, no special treatment is required, but protection of the shoulder is advised to avoid trauma and overuse.

2. Acromioclavicular arthritis: Prolonged and repetitive overuse of the shoulder, such as excessive training in athletes or heavy shoulder work in laborers, can cause wear and degeneration of the acromioclavicular joint cartilage, leading to inflammation. Patients are advised to avoid excessive shoulder activity in daily life and may relieve symptoms through local heat application, massage, and other methods.

3. Adhesive capsulitis (frozen shoulder): Adhesive capsulitis is a chronic aseptic inflammation of the soft tissues surrounding the shoulder joint, often caused by degeneration of shoulder soft tissues, long-term overuse, poor posture, and other factors. Treatment focuses on relieving pain and restoring joint mobility. Patients may undergo physical therapy, massage, acupuncture, and other treatments under the guidance of a traditional Chinese medicine practitioner.

4. Acromioclavicular joint dislocation: Usually caused by direct trauma to the shoulder, resulting in damage to the ligaments and joint capsule of the acromioclavicular joint, with upward displacement of the distal end of the clavicle, thereby increasing the joint space. It is recommended to suspend the affected limb using a shoulder sling or triangular sling for 3–6 weeks under medical guidance to reduce shoulder movement and promote tissue healing.

5. Clavicle fracture: Displacement of the fractured ends after clavicle fracture may cause widening of the acromioclavicular joint space on imaging studies. This condition is usually treated under medical guidance with figure-of-eight bandaging or open reduction and internal fixation surgery.

If an acromioclavicular joint space widening of 6mm is detected, timely medical consultation is recommended for accurate diagnosis and targeted treatment under a physician's guidance.