Adhesive capsulitis (frozen shoulder) is a clinical condition characterized by progressive fibrosis and thickening of the glenohumeral joint capsule, leading to painful and restricted shoulder mobility. Three clinical stages are defined: 'freezing' stage (pain predominant, 2-9 months), 'frozen' stage (stiffness predominant, 4-12 months), and 'thawing' stage (gradual recovery, 5-24 months). It is more common in women and between ages 40-60. Diabetes mellitus, thyroid disease, and prolonged immobilization are predisposing factors. On MRI, the diagnostic triad consists of thickened inferior glenohumeral ligament (IGHL), rotator interval obliteration, and coracohumeral ligament (CHL) thickening. On conventional MR arthrography, decreased joint capacity (<12 mL) and axillary recess obliteration confirm the diagnosis.
Age Range
40-65
Peak Age
50
Gender
Female predominant
Prevalence
Common
Adhesive capsulitis is characterized by chronic inflammation followed by fibrosis of the glenohumeral joint capsule. Initially, synovial inflammation (synovitis) produces capsular hyperemia and edema — this corresponds to the 'freezing' stage and is seen as capsular contrast enhancement on MRI. As the inflammatory process progresses, fibroblast proliferation and myofibroblast transformation begin — these cells express alpha-smooth muscle actin (alpha-SMA) and produce active contraction, similar to Dupuytren contracture. Collagen Type I and Type III accumulation thickens and stiffens the capsule. The rotator interval (RI), coracohumeral ligament (CHL), and inferior glenohumeral ligament (IGHL) are the most affected structures — their fibrosis explains the characteristic pattern of motion restriction: CHL thickening restricts external rotation, IGHL thickening restricts abduction and external rotation. MRI findings directly reflect these pathophysiological processes: capsular thickening on T2-weighted images reflects fibrosis (low signal = mature collagen), capsular enhancement on post-contrast images reflects active inflammation (increased vascular permeability), and axillary recess obliteration reflects capsular contracture.
The MRI diagnostic triad of adhesive capsulitis: (1) thickened IGHL (>4mm), (2) rotator interval fat obliteration, and (3) CHL thickening (>4mm). The combination of these three findings provides high diagnostic reliability for adhesive capsulitis (95%+ positive predictive value). Each finding alone may have variable sensitivity but when evaluated together, they confirm the clinical diagnosis on MRI.
On axial and coronal T2-weighted images, the inferior glenohumeral ligament (IGHL) appears thickened (>4mm, normal <4mm). Due to fibrotic thickening, it shows low signal intensity on T2. The IGHL forms the floor of the axillary recess, and its thickening leads to narrowing of the axillary recess. This finding is the most reliable MRI finding in adhesive capsulitis with 92% sensitivity and 87% specificity.
Report Sentence
The inferior glenohumeral ligament is notably thickened (>4mm) on axial and coronal images, consistent with adhesive capsulitis.
On sagittal T1-weighted images, the rotator interval — the triangular area between the coracoid process and supraspinatus tendon — is normally filled with fat tissue showing high signal. In adhesive capsulitis, this fat tissue is replaced by fibrotic tissue, converting to low signal intensity ('obliteration'). The rotator interval also contains the subscapularis tendon, long head of biceps tendon, and coracohumeral ligament. Loss of the 'empty triangle' appearance on sagittal sections is a diagnostic clue.
Report Sentence
On sagittal T1 images, the rotator interval demonstrates loss of fat signal with fibrotic obliteration, consistent with adhesive capsulitis.
On sagittal and axial T2-weighted images, the coracohumeral ligament (CHL) appears thickened (>4mm, normal 1-2mm). The CHL originates from the coracoid process and inserts on the superior surface of the supraspinatus and subscapularis tendons, forming the roof of the rotator interval. Its thickening specifically correlates with external rotation restriction. Fibrotic CHL shows low signal on T2. On MR arthrography, CHL thickening can be more clearly evaluated because contrast material silhouettes the thin normal CHL structure.
Report Sentence
The coracohumeral ligament is notably thickened (>4mm), consistent with adhesive capsulitis and representing the structural correlate of external rotation restriction.
On coronal T1 and T2-weighted images, the axillary recess — the most inferior portion of the glenohumeral joint capsule beneath the humeral head — shows fibrotic thickening and decreased capacity. The normal axillary recess has thin walls and expands with arm abduction. In adhesive capsulitis, wall thickness increases (>3mm) and recess volume markedly decreases. This finding is more dramatic on MR arthrography: contrast material does not adequately fill the axillary recess and the recess appears 'stuck'.
Report Sentence
The axillary recess demonstrates capsular thickening and narrowing, consistent with capsular contracture due to adhesive capsulitis.
On post-contrast T1-weighted (especially fat-sat) images, diffuse contrast enhancement is seen in the glenohumeral joint capsule and synovial tissue. This finding is particularly prominent in the 'freezing' stage (active inflammatory phase). Enhancement can be seen in all portions of the capsule but is most pronounced in the axillary recess and rotator interval region. In the 'frozen' stage (fibrotic phase), enhancement decreases but capsular thickening persists. Enhancement pattern and intensity can be used for staging and treatment response assessment.
Report Sentence
Diffuse capsular enhancement is seen in the glenohumeral joint capsule on post-contrast images, consistent with adhesive capsulitis in the active inflammatory stage.
On ultrasound, increased power Doppler signal is seen in the rotator interval region — this finding is prominent in the active inflammatory stage (freezing phase). Additionally, the coracohumeral ligament can be evaluated on standard B-mode US and its thickening measured (>4mm). Axillary recess assessment with US is difficult due to its posterior location and bony overlap. US has limited diagnostic value compared to MRI but is useful for point-of-care evaluation and follow-up.
Report Sentence
Increased Doppler vascularity is noted in the rotator interval region, consistent with adhesive capsulitis in the active inflammatory stage.
Criteria
Adhesive capsulitis developing without an identifiable cause. Systemic risk factors such as diabetes mellitus, thyroid disease, and genetic predisposition may be present.
Distinct Features
Capsular thickening and contracture are isolated, with no accompanying rotator cuff pathology or trauma findings. More resistant course and tendency for bilateral involvement in DM patients. 'Pure' capsular pathology on MRI.
Criteria
Adhesive capsulitis developing after trauma, surgery (especially rotator cuff repair), prolonged immobilization, or accompanying intrinsic shoulder pathology.
Distinct Features
MRI shows capsular thickening along with accompanying pathology findings: rotator cuff tendinopathy/tear, subacromial bursitis, glenohumeral osteoarthritis, or postoperative changes. May develop from post-traumatic hemarthrosis.
Criteria
Adhesive capsulitis developing in the setting of diabetes mellitus. Incidence in DM patients is 2-4 times higher than the general population (10-36% vs 2-5%). Risk is highest in insulin-dependent DM.
Distinct Features
More aggressive fibrotic process: capsular thickening is more prominent, more extensive capsular involvement on MRI. Bilateral involvement rate can reach up to 40%. Response to treatment is slower and incomplete. Contracture is more resistant — higher need for surgical intervention.
Distinguishing Feature
PVNS shows T2* blooming (hemosiderin deposition) and lobulated synovial mass, while adhesive capsulitis shows diffuse and smooth capsular thickening without blooming artifact
Distinguishing Feature
Synovial chondromatosis shows pathognomonic intraarticular calcified loose bodies with ring-and-arc calcification on CT; adhesive capsulitis has no calcification
Distinguishing Feature
Subacromial bursitis shows increased fluid and synovial thickening within the bursa on T2, while adhesive capsulitis shows glenohumeral capsule (IGHL, CHL, axillary recess) thickening with typically normal bursa
Distinguishing Feature
Ganglion cyst shows a bright cystic lesion on T2 with thin wall and stalk, while adhesive capsulitis shows diffuse capsular thickening and fibrosis without cystic component
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
6-monthAdhesive capsulitis is generally a self-limiting condition but the recovery process can take 1-3 years. Treatment is determined by stage: pain management in the freezing stage (NSAIDs, corticosteroid injection), physical therapy and stretching exercises in the frozen stage, arthroscopic capsular release or manipulation in resistant cases. Response to conservative treatment is poorer in diabetic patients and surgical intervention may be required. The contralateral shoulder should be monitored clinically due to risk of bilateral involvement.
Adhesive capsulitis is usually a self-limiting condition resolving within 1-3 years. Physical therapy is first-line treatment. In resistant cases, hydrodilation, intra-articular corticosteroid injection, or arthroscopic capsular release may be performed.