Differential Diagnosis for Positive Empty Can Test

Primary Diagnostic Considerations

Subacromial impingement syndrome produces pain with overhead activities and positive impingement signs, with Neer's test being 88% sensitive and Hawkins' test being 92% sensitive, often associated with scapular dyskinesis and rotator cuff weakness in patients with shoulder pain 1

Rotator cuff tendinopathy presents with localized tenderness and load-related pain during activity, with pain possibly present during the empty can test but typically with less severe weakness, and ultrasound or MRI shows tendon thickening and degeneration without discontinuity in patients with rotator cuff symptoms 2
The American Academy of Family Physicians recommends that patients with rotator cuff tendinopathy should undergo ultrasound or MRI to confirm the diagnosis, which shows tendon thickening and degeneration without discontinuity 2
Subscapularis tendon tears can coexist and produce weakness patterns, and the American College of Radiology recommends MRI for diagnosis of subscapularis tendon tears, which can produce weakness patterns in patients with shoulder weakness 4

The American College of Radiology recommends ultrasound as the initial imaging modality for full-thickness tears, with 91% sensitivity and 88% specificity, and MRI without contrast when diagnosis remains unclear or surgical planning is needed, with 95% sensitivity and specificity 3, 4
Plain radiographs should be used initially to exclude bony pathology, though they cannot visualize tendon tears, and the American Academy of Family Physicians recommends plain radiographs as the initial imaging modality to exclude bony pathology in patients with shoulder pain 2, 3

Younger athletes more commonly have secondary impingement from rotator cuff weakness rather than structural tears, and the American College of Sports Medicine recommends conservative management for younger athletes with secondary impingement 1
Partial-thickness tears require 3-6 months of conservative management before considering surgery, and the American Academy of Orthopaedic Surgeons recommends conservative management for partial-thickness tears, which require 3-6 months of conservative management before considering surgery 3