Adhesive capsulitis of the shoulder

Adhesive capsulitis of the shoulder, also known as frozen shoulder, is a condition characterized by thickening and contraction of the shoulder joint capsule and surrounding synovium. Adhesive capsulitis can rarely affect other sites such as the ankle ⁸.

Epidemiology

The incidence in the general population is thought to be 3-5%. Adhesive capsulitis typically affects women in their 5^th to 6^th decades, although patients with co-morbidities such as diabetes mellitus may develop the condition at earlier ages. The incidence in patients with diabetes is reported to be 2 to 4 times higher than in the general population.

Clinical presentation

The characteristic symptom is shoulder pain and associated with it a painfully limited range of motion. The pain also occurs at night, which negatively affects sleep quality ²².

Adhesive capsulitis presentation can be broken into three distinct stages:

• freezing: painful stage 

  • patients may not present during this stage because they think that eventually, the pain will resolve if self-treated

  • as the symptoms progress, pain worsens and both active and passive range of motion (ROM) becomes more restricted

  • this can eventually result in the patient seeking medical consultation

  • typically lasts between 3 and 9 months and is characterized by acute synovitis of the glenohumeral joint

• frozen: transitional stage

  • most patients will progress to the second stage

  • during this stage, shoulder pain does not necessarily worsen

  • because of pain at the end of the range of motion, arm movement may be limited, causing muscular disuse

  • can last between 4 to 12 months

  • the common capsular pattern of limitation has historically been described as diminishing motions with external shoulder rotation being the most limited, followed closely by shoulder flexion, and internal rotation

  • a point is eventually reached in the frozen stage where pain does not occur at the end of the range of motion

• thawing stage

  • begins when the range of motion starts to improve

  • lasts anywhere from 12 to 42 months and is defined by a gradual return of shoulder mobility

Pathology

Adhesive capsulitis is divided into two main types: 

• primary or idiopathic

  • absence of preceding trauma

• secondary 

  • major or minor repetitive trauma

  • shoulder or thoracic surgery

  • endocrine, e.g. diabetes, hyperthyroidism ¹²

  • rheumatological conditions

Radiographic features

Fluoroscopy

Described features of fluoroscopic arthrography include:

• limited injectable fluid capacity of the glenohumeral joint 

• small dependent axillary fold

• small subscapularis bursa

• irregularity of the anterior capsular insertion at the anatomic neck of the humerus

• lymphatic filling may be present

Ultrasound

• limitation of movement of the supraspinatus is considered a sensitive feature ⁷

• limited external rotation, identified when positioning for subscapularis tendon assessment

• thickened coracohumeral ligament (CHL) can be suggestive ⁹

• thickening of the inferior glenohumeral capsule ¹⁶

• hypoechoic soft tissue around the long head of biceps at rotator interval ^13,20

• increased vascularity of the long head of the biceps at rotator interval ^13,20

MRI/MR arthrography

The signs of adhesive capsulitis are variable with some but rarely all of the following expected to be present:

• T2 hyperintensity of the inferior glenohumeral ligament on T2 fat-saturated sequences ^17,19

• coracohumeral ligament thickening >4-7 mm ^4,19

• subcoracoid triangle sign ⁴

• joint capsule thickening ²

  • anterior capsule thickness >3.5 mm and abnormal hyperintensity ¹⁴

  • axillary pouch thickening >3-4 mm has been specicic for adhesive capsulitis in some studies ^1,2,5 but not in others ^3,4,17-19

• abnormal soft tissue thickening within the rotator interval with signal alteration ¹⁸

• abnormal soft tissue encasing the biceps anchor ¹⁸

• variable capsular and synovial enhancement within the axillary recess and rotator interval ¹⁸

• distention of the subscapular recess is very suggestive ²¹

Chronic frozen shoulder may show low T2 signal and pericapsular scarring ¹⁵. 

Treatment and prognosis

Adhesive capsulitis is typically a self-limiting disease that improves over 1-2 years. Treatment options include:

• physiotherapy

• corticosteroid injections

• glenohumeral hydrodilatation

• closed manipulation under anesthesia

• arthroscopic capsular release with lysis of adhesions