Frozen shoulder, also known as “adhesive capsulitis” or “periarthritis of the shoulder,” is a common condition characterized by pain and loss of range of motion in the shoulder. Frozen shoulder is a collection of symptoms with the hallmark feature being loss of both active and passive shoulder motion. The exact etiology remains unclear, and controversy exists about whether the underlying process is an inflammatory, fibrosing, or neurodystrophic condition. Regardless of the pathoanatomy, the final common pathway is a contracted glenohumeral joint capsule that restricts all planes of glenohumeral motion (Fig. 42-1).

The diagnosis of frozen shoulder is essentially one of exclusion and should not be made until other intrinsic causes of shoulder pain and stiffness have been ruled out. In most cases, the natural history of frozen shoulder is one of eventual resolution. In contrast, many intrinsic shoulder conditions that also present with pain and stiffness, such as impingement syndrome, rotator cuff tears, and glenohumeral arthritis may not improve without appropriate management.

Frozen shoulder is often classified into primary and secondary forms. Primary frozen shoulder is idiopathic, while secondary frozen shoulder is associated with another medical condition. These conditions include cervical disk disease, central nervous system disorders, ischemic cardiac disease, pulmonary disease, diabetes mellitus, and thyroid dysfunction (Table 42-1). Diabetes mellitus has the highest association with frozen shoulder, and the incidence is two to four times higher in diabetic patients than in the normal population. Frozen shoulder occurs slightly more often in women than men and is rare in patients under the age of 40.^1,2 Recurrence after resolution is rare.

Patients with frozen shoulder traditionally progress through three overlapping clinical phases during a period of 18 to 24 months. The initial or “inflammatory” phase (a few weeks to 9 months) is characterized by the insidious onset of pain and stiffness around the shoulder. During the second or “adhesive” phase (4-12 months), the pain gradually subsides but the stiffness persists. The final or “resolution” phase (5-24 months) is characterized by a spontaneous but gradual improvement in range of motion.

A careful clinical history and physical examination is crucial in making the diagnosis of frozen shoulder, because the disorder represents a symptom complex, rather than a specific diagnostic entity.³ Patients typically present during the initial clinical phase (inflammatory) and report the insidious onset of pain and shoulder stiffness. The pain can be of varying intensity, and rest and/or night pain are also commonly reported. Stiffness is reflected in the gradual loss of function. Patients report difficulty performing overhead activities, as well as activities behind their back or out to the side. Since these symptoms closely resemble those found in rotator cuff pathology, it is important to combine this information with a good physical examination and imaging studies before a diagnosis of frozen shoulder is made.

The physical examination is critical in ruling out other shoulder pathology and confirming the diagnosis of frozen shoulder. As with all suspected shoulder disorders, a careful examination of the cervical spine should be performed to rule out cervical pathology that may cause referred pain in the shoulder. On inspection, the patient’s arm is often held in an adducted and internally rotated position. Mild disuse atrophy of the deltoid and rotator cuff may also be observed. Palpation of the shoulder may reveal diffuse nonspecific tenderness over the entire shoulder girdle, particularly in the early inflammatory phase; however, patients may have more focal or more severe tenderness to palpation along the glenohumeral joint line.