What are the diagnostic criteria for subacromial impingement syndrome?

From the Guidelines

Diagnosis of subacromial impingement syndrome is primarily based on clinical evaluation and imaging studies. The diagnostic criteria include a combination of physical examination findings, such as pain with abduction, external rotation, and specific tests like the Hawkins’ test 1 and Neer’s test 1. These tests are sensitive but not specific for impingement, with the Hawkins’ test having a sensitivity of 92% and specificity of 25%, and the Neer’s test having a sensitivity of 88% and specificity of 33% 1.

• Imaging studies, including radiographs and magnetic resonance imaging (MRI) 1, may be ordered to confirm the diagnosis and rule out other conditions.
• MRI is the most sensitive modality for detecting rotator cuff tendinopathy and subacromial bursitis 1, and can aid in detecting osseous and soft tissue abnormalities that may predispose to or be the result of shoulder impingement.
• Laboratory tests, such as complete blood count and erythrocyte sedimentation rate, may be ordered to rule out inflammatory or infectious causes of shoulder pain.
• The presence of tendinosis or tendinopathy can be suggested by signal intensity abnormalities on MRI, and partial-thickness tears of the rotator cuff can be seen inferiorly at the articular surface, superiorly at the bursal surface or within the tendon substance 1.

From the Research

Diagnostic Criteria for Subacromial Impingement Syndrome

The diagnostic criteria for subacromial impingement syndrome involve a combination of clinical tests and imaging findings. The following are some of the key diagnostic criteria:

• Clinical tests:
  • Hawkins test: sensitive for identifying subacromial impingement syndrome 2
  • Neer test: specific for identifying subacromial impingement syndrome 2
  • Jobe's test: indicates supraspinatus involvement with high specificity 2
• Imaging findings:
  • Subacromial-subdeltoid bursitis 3, 4
  • Supraspinatus tendinopathy 3, 4
  • Rotator cuff tendon tears 3, 4
  • Subacromial osteophytic spurs 4
  • Acromioclavicular joint capsular hypertrophy and osteophytosis 4
• Stages of impingement syndrome:
  • Stage I: edema and hemorrhage of the supraspinatus tendon 5
  • Stage II: bursal inflammation and fibrosis, as well as tendinopathy 5
  • Stage III: tear of the rotator cuff 5

Imaging Modalities

Different imaging modalities can be used to diagnose subacromial impingement syndrome, including:

• Ultrasonography: useful for screening and diagnosis, but with high interobserver variability 5, 2
• Magnetic Resonance Imaging (MRI): effective in demonstrating soft tissue and bony abnormalities, and considered the method of choice for evaluating the rotator cuff and surrounding structures 5, 4
• MR arthrography: may be indicated in preoperative planning, but not universally accepted 5
• Standard radiographs: useful for demonstrating subchondral sclerosis, subacromial spurs, and form anomalies of the acromion, as well as for differential diagnosis 5