Adhesive Capsulitis (Frozen Shoulder) Workup

Updated: May 17, 2017
  • Author: Jefferson R Roberts, MD; Chief Editor: S Ashfaq Hasan, MD  more...
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Workup

Approach Considerations

Frozen shoulder syndrome (FSS) is a clinical diagnosis. Laboratory and imaging studies can be used to rule out other conditions and to confirm the likelihood of the correct diagnosis. Accurate diagnosis is essential because the treatment for FSS differs from the treatment for other shoulder entities. 

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Laboratory Studies

Laboratory studies rarely are required for the evaluation of adhesive capsulitis. However, if a predisposing medical condition that may be contributing to adhesive capsulitis is suggested, the following tests may be ordered:

  • Complete blood cell count (CBC)
  • Erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • Blood glucose
  • Hemoglobin A1c 
  • Thyroid-stimulating hormone (TSH)
  • Free thyroxine index (FTI)

Although an orthopedic surgeon may order these tests, results should be forwarded to the patient's primary care physician for further evaluation.

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Imaging Studies

Imaging studies are not indicated in the diagnosis of FSS. No imaging modality has been definitively shown to provide greater diagnostic value, due to the heterogeneity of techniques used, and the presence of potential confounding factors limits definitive conclusions from imaging study findings. .However, more recent studies are moving toward defining the criteria for imaging studies to aid in the staging of FSS. Common findings in FSS are thickening of the coracohumeral and inferior glenohumeral ligaments. Zappia reports that rotator interval fat pad obliteration has 100% specificity for adhesive capsulitis. [37]

Radiography

Routine radiographs do not have a role in the diagnosis of FSS. However, plain films of the shoulder should be obtained in all cases to rule out any other pathologic process. These radiographs should include the following [38] :

  • Anteroposterior (AP) view of the glenohumeral joint in neutral rotation
  • Supraspinatus outlet view
  • Axillary lateral view (if possible)

Ultrasonography

Ultrasound (regular and Doppler) for the diagnosis of FSS remains controversial. Overall, these studies have shown utility for measurement of acohumeral ligament thickness and presence of a hypoechoid region with increased vascularity in the rotator interval, with fibrovascular inflammatory tissue. 

Arthrography

Arthrography, which involves intra-articular injection of diluted iodinated contrast medium, can aid in both the diagnosis and treatment of FSS. The following findings are suggestive of FSS [37] :

  • Reduced capsular distention, with irregular internal profile and internal septa (medial leakage of contrast)
  • Lack of distention of subscapular bursa
  • Atypical contrast leakage in the biceps sheath

Milena et al report that the findings on computed tomography (CT) arthrography are comparable to those on magnetic resonance imaging (MRI). Diagnostic signs are decreased width of the axillary recess and thickening of the lateral wall. [39]

Magnetic resonance imaging

MRI is not initially indicated in cases of FSS. Due to the global pain associated with FSS, MRI is an expensive and nonspecific test. However, if the patient does not improve after a period of time (6 wk to 3 mo), then MRI is appropriate to rule out a possible rotator cuff tear or intra-articular pathology. [40, 41] In addition, recent studies suggest that MRI findings can provide positive support for a diagnosis of FSS. Chi et al concluded that non-contrast MRI (ie, without direct MRI arthrography), in conjunction with clinical criteria, can support accurate diagnosis of FSS . [42] The following features on MRI strongly suggest FSS [37, 43] :

  • Inferior glenohumeral ligament hyperintensity
  • Capsular and coracohumeral ligament thickening
  • Synovial hypertrophy
  • Tissue scarring at the rotator interval 
  • Edema of the axillary recess
  • Obliteration of the fat triangle under the coracoid process
  • Extracapsular edema
  • High signal intensity bordering the outer capsular surface of the shoulder joint (fat-suppressed T2-weighted study)

Zappia et al hypothesize that the high pericapsular signal intensity corresponds to hypervascular synovitis during the frozen phase of FSS. [37] Park et al have correlated MRI findings with the clinical stage of FSS; see Table 3, below. [43]

Table 3 MRI findings according to clinical stage of FSS (Open Table in a new window)

Stage Joint capsular thickness (mm) in humeral portion of the axillary access Joint capsule edema  in humeral portion of axillary recess Obliteration of subcoracoid fat triangle
1 4.67 97% 74%
2 3.73 83% 56%
3 3.67 64% 21%

 

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Histologic Findings

Common arthroscopic findings in patients with adhesive capsulitis are the following:

  • Proliferative synovitis
  • Capsular and intra-articular subscapularis tendon thickening
  • Fibrosis
  • Chronic inflammatory cells

Significant synovitis is noted mostly in the anterior capsule, but is not limited to that area. In addition, most patients demonstrate significant subacromial fibrosis. One study found that approximately 40% of patients had significant subacromial fibrosis, regardless of preoperative etiology.

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