Acromioclavicular (AC) joint pain is discomfort localized at the top of the shoulder, specifically where the clavicle (collarbone) meets the acromion (part of the shoulder blade). It's often caused by osteoarthritis or injury to the joint.
Understanding the Acromioclavicular Joint
The AC joint is a small joint that plays a crucial role in shoulder movement and stability. It allows for a wide range of arm motion and helps to transfer forces from the arm to the rest of the body.
Causes of Acromioclavicular Joint Pain
Several factors can contribute to AC joint pain:
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Osteoarthritis (AC Joint Arthrosis): This is the most common cause, especially in middle-aged and older adults. It involves the gradual wearing down of cartilage within the joint, leading to pain and stiffness.
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Injury: Direct trauma to the shoulder, such as a fall or a sports injury, can damage the AC joint, resulting in sprains, separations, or fractures.
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Repetitive Use: Overuse or repetitive overhead activities, common in certain jobs or sports (e.g., weightlifting, baseball), can stress the AC joint and lead to inflammation and pain.
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AC Joint Separation: This occurs when the ligaments that hold the AC joint together are torn, causing the clavicle to separate from the acromion. It's typically graded based on the severity of the ligament damage.
Symptoms of Acromioclavicular Joint Pain
Common symptoms include:
- Localized Pain: Pain directly over the AC joint, at the top of the shoulder.
- Pain with Movement: Pain that worsens with arm movements, especially reaching across the body or overhead.
- Tenderness: Tenderness to the touch over the AC joint.
- Swelling: Possible swelling around the AC joint.
- Clicking or Popping: A clicking or popping sensation in the joint during movement.
- Limited Range of Motion: Difficulty moving the arm in certain directions.
- Pain at night: Pain that worsens at night, especially when lying on the affected side.
Diagnosis and Treatment
A physical examination, including specific maneuvers to stress the AC joint, along with X-rays, are typically used to diagnose AC joint pain. Treatment options vary depending on the severity and cause of the pain and may include:
- Rest and Activity Modification: Avoiding activities that aggravate the pain.
- Ice and Heat: Applying ice or heat to the affected area to reduce inflammation and pain.
- Pain Medication: Over-the-counter pain relievers like ibuprofen or naproxen, or stronger prescription medications if needed.
- Physical Therapy: Exercises to strengthen the surrounding muscles and improve range of motion.
- Cortisone Injections: Corticosteroid injections into the AC joint to reduce inflammation and pain.
- Surgery: In severe cases, surgery may be necessary to remove damaged cartilage or repair torn ligaments.
In summary, acromioclavicular joint pain is a common condition with various causes, characterized by localized pain and discomfort at the top of the shoulder, often limiting arm movement. Prompt diagnosis and appropriate treatment are essential for managing the pain and restoring shoulder function.
