Frozen shoulder has been defined by the American Academy of Orthopedic Surgeons as: “A condition of varying severity characterized by the gradual development of global limitation of active and passive shoulder motion where radiographic findings other than osteopenia are absent.” The condition is also characterized by severe shoulder pain.
Frozen shoulder is also referred to as adhesive capsulitis, painful stiff shoulder, and periarthritis. We will use the term “frozen shoulder” throughout this review. This topic will review the diagnosis and management of frozen shoulder. Evaluation of the patient with undifferentiated shoulder pain and other specific causes of shoulder pain or dysfunction are discussed separately. (See “Evaluation of the adult with shoulder complaints” and “Rotator cuff tendinopathy” and “Presentation and diagnosis of rotator cuff tears”.)
EPIDEMIOLOGY
The lifetime prevalence of frozen shoulder is estimated to be 2 to 5 percent of the general population.The condition is most common in the fifth and sixth decades of life, with the peak age in the mid-50s. Onset before the age of 40 is rare. Women are more often affected than men. The non-dominant shoulder is slightly more likely to be affected. In 6 to 17 percent of patients, the other shoulder becomes affected within five years.
Frozen shoulder occurs predominantly unilaterally and is usually self-limited, although evidence about prognosis is limited, and the course can be prolonged, in some cases lasting over two to three years. Some studies suggest that up to 40 percent of patients have persistent but mostly mild symptoms beyond three years, and 15 percent have long-term disability. Patients with type 1 diabetes seem to have a more prolonged course than in the non-diabetic population.
ETIOLOGY AND PATHOPHYSIOLOGY
Frozen shoulder can be primary (or idiopathic) but is often associated with other diseases and conditions. Patients with diabetes mellitus are at greater risk of developing frozen shoulder, with a prevalence of 10 to 20 percent. However, a more recent cross-sectional study showed that the point prevalence of frozen shoulder in patients with long-lasting type 1 diabetes was as high as 59 percent and the lifetime prevalence 76 percent.