Shoulder Joint Injection
The shoulder is the site of multiple injuries and inflammatory conditions that lend themselves to diagnostic and therapeutic injection. Joint injection should be considered after other therapeutic interventions such as nonsteroidal anti-inflammatory drugs, physical therapy, and activity-modification have been tried. Indications for glenohumeral joint injection include osteoarthritis, adhesive capsulitis, and rheumatoid arthritis. For the acromioclavicular joint, injection may be used for diagnosis and treatment of osteoarthritis and distal clavicular osteolysis. Subacromial injections are useful for a range of conditions including adhesive capsulitis, sub-deltoid bursitis, impingement syndrome, and rotator cuff tendinosis.

Scapulothoracic injections are reserved for inflammation of the involved bursa. Persistent pain related to inflammatory conditions of the long head of the biceps responds well to injection in the region. The proper technique, choice and quantity of pharmaceuticals, and appropriate follow-up are essential for effective outcomes.

The glenohumeral joint represents the articulation of the humerus with the glenoid fossa, and it is the most mobile joint in the body. The glenohumeral joint is not a true ball and socket joint. The articulation is stabilized by the soft tissue configurations of a number of ligaments and muscles, including the four muscles of the rotator cuff (supraspinatus, infraspinatus, teres minor, and subscapularis) that serve as dynamic stabilizers of the joint. Static stabilizers include the joint capsule, the glenoid labrum, and the glenohumeral ligaments.

Joint injection in this area should be considered only after other appropriate therapeutic interventions have been tried. These include the use of nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, and other disease-modifying agents for rheumatoid arthritis. There are three major indications for a glenohumeral joint injection: osteoarthritis, adhesive capsulitis (frozen shoulder), and rheumatoid arthritis.

Osteoarthritis of the shoulder typically occurs in older persons or following traumatic injury in younger persons. Patients usually present with chronic pain, decreased range of motion, and accompanying weakness. Although radiographs can assist in the diagnosis, findings do not always correlate with clinical symptoms or functioning. Adhesive capsulitis is a condition typically occurring in middle-aged and older adults, and it is usually associated with a traumatic injury or nonuse of the shoulder secondary to pain, discomfort, or prolonged immobilization. The condition is more common in women and persons with diabetes. There is often accompanying tendinosis or bursitis. Rheumatoid arthritis is a systemic inflammatory disease of autoimmune nature that involves inflammation of the synovium of the shoulder joint.

Diagnosis of glenohumeral joint pathology is suspected clinically, and on physical examination, the physician may find painful and decreased range of motion, generalized weakness, and palpable crepitus with shoulder movement. Radiographs may be helpful in confirming the diagnosis. Historical factors also cue the diagnosis, with osteoarthritis being more insidious in onset, and rheumatoid arthritis, while chronic in nature, being punctuated by periodic exacerbations secondary to inflammation. In adhesive capsulitis, progressive worsening of pain occurs with loss of motion and a firm, painful end point in the range of motion during physical examination.

The glenohumeral joint can be injected from an anterior, posterior, or superior approach. The anterior and posterior approaches, which are used more often, are described here. In each case, the joint is most easily accessible with the patient sitting, the patient's arm resting comfortably at the side, and the shoulder externally rotated. Essential landmarks to palpate before performing this injection include the head of the humerus, the coracoid process, and the acromion.

Follow-up care should include the following recommendations. Patients should remain seated or placed in supine position for several minutes after the injection. To ascertain whether the pharmaceuticals have been delivered to the appropriate location, the joint or area may be put through passive range of motion. The patient should remain in the office to be monitored for 30 minutes after the injection, and the patient should avoid strenuous activity involving the injected region for at least 48 hours. Patients should be cautioned that they might experience worsening symptoms during the first 24 to 48 hours, related to a possible steroid flare, which can be treated with ice and NSAIDs. A follow-up examination should be arranged within two-three weeks.