Acromioclavicular Joint Pain
THE CLINICAL SYNDROME
The acromioclavicular joint is vulnerable to injury from both acute trauma and repeated microtrauma. Acute injuries frequently take the form of falls directly onto the shoulder when playing sports or falling from bicycles. Repeated strain from throwing injuries or working with the arm raised across the body may also result in trauma to the joint. After trauma, the joint may become acutely inflamed, and if the condition becomes chronic, arthritis of the acromioclavicular joint may develop.
SIGNS AND SYMPTOMS
The patient suffering from acromioclavicular joint dysfunction will frequently complain of pain when reaching across the chest. Often, the patient will be unable to sleep on the affected shoulder and may complain of a grinding sensation in the joint, especially on first awakening. Physical examination may reveal enlargement or swelling of the joint with tenderness to palpation. Downward traction or passive adduction of the affected shoulder may cause increased pain. If there is disruption of the ligaments of the acromioclavicular joint, these maneuvers may reveal joint instability.
The pain of acromioclavicular joint dysfunction is made worse by reaching across the chest.
nitial treatment of the pain and functional disability associated with acromioclavicular joint pain should include a combination of the nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors and physical therapy. The local application of heat and cold may also be beneficial. For patients who do not respond to these treatment modalities, an intra-articular injection of local anesthetic and steroid may be a reasonable next step.
Intra-articular injection of he acromioclavicular joint is performed by placing the patient in the supine position and preparing with antiseptic solution the skin overlying the superior shoulder and distal clavicle. A sterile syringe containing 1.0 mL of 0.25% preservative-free bupivacaine and 40mg methylprednisolone is attached to a 1 ½ inch 25-gauge needle using strict aseptic technique. With strict aseptic technique, the top of the acromion is identified, and at a point approximately 1 inch medially, the acromioclavicular joint space is identified. The needle is then carefully advance through the skin and subcutaneous tissues through the joint capsule into the joint. If bone is encountered, the needle is withdrawn into the subcutaneous tissue and redirected slightly more medially. After the joint space is entered, the contents of the syringe are gently injected. There should be some resistance to injection because the joint space is small and the joint capsule is dense. If significant resistance is encountered, the needle is probably in a ligament and should be advance slightly into the joint space until the injection proceeds with only limited resistance. If no resistance is encountered on injection, the joint space is probably not intact and magnetic resonance imaging is recommended. The needle is then removed, and a sterile pressure dressing and ice pack are placed at the injection site.
Proper needle placement for acromioclavicular joint injection.