Injection Technique for Frozen Shoulder Syndrome

Indications and Clinical Considerations

The term frozen shoulder describes a constellation of clinical symptoms, including the unilateral progressive limitation of passive and active range of motion of the shoulder and pain on range of motion ( Fig. 50.1 ). Usually, the patient first notes difficulty in reaching behind to fasten clothing such as a bra. Patients exhibit a positive Apley scratch test; that is, they are unable to scratch their lower back with the affected extremity. The limitation of shoulder range of motion then progresses to limit the patient’s ability to elevate the shoulder. The pain is constant, with worsening on use of the shoulder group. The pain is localized to the anterolateral aspect of shoulder and may radiate into the lateral neck and upper anterior chest. Some patients report a grating or popping sensation with use of the joint, and crepitus may be present on physical examination. Frozen shoulder is distinguishable from other painful conditions of the shoulder, such as tendinitis and bursitis, in that the limitation of range of motion associated with frozen shoulder affects both passive and active range of motion, whereas tendinitis and bursitis affect only active range of motion.

Frozen shoulder is thought to be caused by a progressive adhesive capsulitis secondary to chronic inflammation of the structures of the shoulder ( Fig. 50.2 ). Although coexistent tendinopathy or bursitis may be present, the inflammatory changes associated with frozen shoulder selectively affect the ligaments and joint capsule. Individuals with diabetes are more commonly affected by frozen shoulder than the general population, as are patients with collagen vascular diseases, such as polymyalgia rheumatica. The collagen vascular diseases generally manifest as a polyarthropathy rather than as a monoarthropathy limited to the shoulder joint.

Frozen shoulder also may be seen after myocardial infarction, fractures of the humeral head, and paralytic stroke. In this setting, untreated frozen shoulder may progress to a reflex sympathetic dystrophy with associated vasomotor, sudomotor, and trophic changes.

Plain radiographs are indicated for all patients with shoulder pain. On the basis of the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging and ultrasound imaging of the shoulder are indicated if a rotator cuff tear is suspected. Patients suffering from frozen shoulder will exhibit characteristic neovascularization on arthroscopy ( Fig. 50.3 ).

Clinically Relevant Anatomy

The rounded head of the humerus articulates with the pear-shaped glenoid fossa of the scapula. The articular surface is covered with hyaline cartilage that is susceptible to arthritis. The rim of the glenoid fossa is composed of a fibrocartilaginous layer called the glenoid labrum, which is susceptible to trauma should the humerus be subluxed or dislocated. The joint is surrounded by a relatively lax capsule that allows the wide range of motion of the shoulder joint at the expense of decreased joint stability. It is this capsule that, along with the shoulder ligaments, is most severely affected in frozen shoulder syndrome. The joint capsule is lined with a synovial membrane that attaches to the articular cartilage. This membrane gives rise to synovial tendon sheaths and bursae that are subject to inflammation. The shoulder joint is innervated by the axillary and suprascapular nerves.

The major ligaments of the shoulder joint are the glenohumeral ligaments in front of the capsule, the transverse humeral ligament between the humeral tuberosities, and the coracohumeral ligament, which stretches from the coracoid process to the greater tuberosity of the humerus (see Fig. 50.2 and Fig. 50.4 ). Along with the accessory ligaments of the shoulder, these major ligaments provide strength to the shoulder joint. The strength of the shoulder joint is also dependent on short muscles that surround the joint: the subscapularis, the supraspinatus, the infraspinatus, and the teres minor. These muscles and their attaching tendons are susceptible to trauma and to wear and tear from overuse and misuse.