Adhesive Capsulitis

Adhesive capsulitis is a self-limited clinical syndrome characterized by painful, gradual loss of active and passive glenohumeral motion. Patients are typically women between 40 and 60 years of age who have had symptoms for at least a month, but sometimes for years. Interestingly, the nondominant hand is more frequently involved. While considered a self-limited condition, complete resolution of symptoms can sometimes take years.

The term frozen shoulder is often used interchangeably with adhesive capsulitis; however, many conditions can cause a stiff and painful shoulder. The term adhesive capsulitis should be reserved for the distinct pathological entity of inflammation of the joint capsule and synovium, leading to thickening, contraction, and formation of adhesions.

The process can be primary (idiopathic) or secondary. Causes of secondary adhesive capsulitis include trauma (10% of cases), surgery, degenerative disease, rotator cuff tear, inflammatory disease, metabolic disease (e.g., diabetes, thyroid dysfunction), and autoimmune disease.

Four clinical and arthroscopic stages of adhesive capsulitis have been described.

• Stage 1: This stage represents acute synovitis without adhesions or capsular contracture. Patients present with less than 3 months of pain (typically at the deltoid insertion) that is achy at rest and sharp with movement. Night pain is a common complaint. Limitation of movement, if present, is reversed by intra-articular injection of anesthetic. The symptoms are nonspecific and can be similar to those of calcific tendinitis, early osteoarthritis, and rotator cuff injury.
• Stage 2: This stage represents acute synovitis and progressive capsular contracture due to subsynovial scar formation. This stage is also known as the freezing stage. Patients still have pain, which may have increased in severity and is worse at night. Motion is restricted and is partially restored with intra-articular injection of anesthetic.
• Stage 3: This stage represents "burned out" synovitis and a hypercellular, collagenous capsule. Also referred to as the frozen stage, this stage is characterized clinically by 9 to 15 months of significant stiffness with or without pain at the end range of motion. The restricted motion does not improve with intra-articular injection of anesthetic.
• Stage 4: This stage is characterized by fully mature adhesions. Also known as the chronic or thawing stage, patients present with minimal pain, sometimes with a gradual improvement in motion. The latter is controversial, as patients tend to under-estimate the range of motion when compared to objective assessments.

Radiographs are performed at the the initial stage to exclude other causes of a stiff shoulder (arthritis, calcific tendinosis). MRI can be performed to exclude rotator cuff tear.

MRI findings cannot reliably differentiate the different stages with two exceptions. In stage 2 disease, there is increased signal intensity of the joint capsule and synovium, reflecting the acute synovitis. The capsular and synovial thickening, as measured in the axillary pouch (pink arrow), is greatest in stage 2 disease (mean thickness of 7.5 mm, compared to ~4 mm for stages 1 and 4 and 5.5 mm in stage 3).

Other MRI findings are not specific to the stage of disease. Soft tissue signal intensity has been described in the rotator interval (white arrows) with or without encasement of the superior glenohumeral and coracohumeral ligaments and extension to the biceps tendon anchor. The soft tissue usually has increased signal intensity on PD-FS images and enhances on post-contrast sequences. This is best seen on sagittal images. Axial images are also useful, but partial volume averaging of the subscapularis muscle may mimic a rotator interval lesion.

Thickening of the coracohumeral ligament can also be seen, although earlier studies have not found a significant difference in thickness between symptomatic patients and control subjects.

On arthrography, the tight joint manifests as decreased capacity to joint injection, although no significant difference has been found in articular fluid volumes between patients with adhesive capsulitis and asymptomatic controls.

Treatment consists of physical therapy, intra-articular corticosteroid injection, closed manipulations, hydrodilatation, and anterior capsulotomy.

References

• Connell D, Padmanabhan R, Buchbinder R. Adhesive capsulitis: role of MR imaging in differential diagnosis. Eur Radiol. 2002 Aug;12(8):2100-6.
• Emig EW, Schweitzer ME, Karasick D, Lubowitz J. Adhesive capsulitis of the shoulder: MR diagnosis. AJR Am J Roentgenol. 1995 Jun;164(6):1457-9.
• Neviaser AS, Hannafin JA. Adhesive capsulitis: a review of current treatment. Am J Sports Med. 2010 Nov;38(11):2346-56. Epub 2010 Jan 28.
• Sofka CM, Ciavarra GA, Hannafin JA, Cordasco FA, Potter HG. Magnetic resonance imaging of adhesive capsulitis: correlation with clinical staging. HSS J. 2008 Sep;4(2):164-9.