Rotator Cuff Tear: Diagnosis and Management
Diagnosis
The combination of a positive empty can test (supraspinatus weakness) and positive lift-off test (subscapularis weakness) indicates a multi-tendon rotator cuff tear involving at least the supraspinatus and subscapularis tendons. 1
Clinical Test Interpretation
The empty can test demonstrates 77.8% sensitivity for rotator cuff tears, but critically, pain provocation during this test has 96% specificity and 96% positive predictive value for differentiating true rotator cuff pathology from other conditions like cervical spondylotic amyotrophy. 2
The lift-off test specifically evaluates subscapularis integrity, and when positive alongside supraspinatus weakness, suggests a more extensive tear pattern. 3
When three clinical findings are present—supraspinatus weakness, weakness in external rotation, and impingement signs—the patient has a 98% probability of having a rotator cuff tear. 1
Imaging Algorithm
Plain radiographs must be obtained first: anteroposterior views in internal and external rotation plus axillary or scapular Y view to exclude fractures, dislocations, and osseous pathology. 4, 5
Following normal or noncontributory radiographs, MRI shoulder without IV contrast is the optimal next imaging study, as it is "generally considered the best modality for adequately assessing most soft tissue injuries, including labroligamentous, cartilage, and rotator cuff pathology." 4, 5
Why MRI Without Contrast?
MRI without contrast demonstrates 94% sensitivity and 93% specificity for full-thickness rotator cuff tears, with performance comparable to MR arthrography. 5
Standard intravenous gadolinium contrast provides no additional diagnostic benefit for rotator cuff evaluation and unnecessarily exposes patients to contrast-related risks. 5
MR arthrography should be reserved only for cases where non-contrast MRI is equivocal for partial-thickness tears, not as the initial study. 4, 5
Ultrasound has variable interobserver agreement for partial-thickness tears and is highly operator-dependent, making MRI more reliable. 5
Critical MRI Findings That Guide Treatment
MRI assessment of tendon retraction, muscle atrophy, and fatty infiltration is essential for determining whether conservative versus operative repair is appropriate, and for providing postoperative prognosis. 4
Treatment Approach
Most rotator cuff injuries should initially be treated conservatively with NSAIDs, corticosteroid injections, and functional rehabilitation therapy, with surgical management reserved for refractory cases that have exhausted conservative measures. 4, 6
Conservative Management Protocol
Complete rest from aggravating activities until asymptomatic, followed by rehabilitation emphasizing rotator cuff and scapular stabilizer strengthening, re-establishing proper shoulder mechanics, and restoring range of motion. 4
A progressive throwing or functional program over 1 to 3 months may be initiated once pain-free motion and strength have been achieved. 4
Injury prevention programs are essential for long-term care and prevention of recurrent injuries. 6
When to Consider Surgery
Surgical repair should be considered when conservative treatment fails after an adequate trial (typically 3-6 months), or in cases of acute traumatic full-thickness tears in younger active patients where early repair may prevent muscle atrophy and fatty infiltration. 4, 6
Delayed rotator cuff repair up to 4 months has not shown adverse outcomes, allowing adequate time for conservative management trials. 5
Critical Pitfalls to Avoid
Do not proceed directly to orthopedic referral without advanced imaging, as MRI is essential to confirm the diagnosis, characterize tear extent and quality of remaining tendon, and guide appropriate treatment planning. 5
Avoid ordering CT in the acute setting, as non-contrast CT cannot assess rotator cuff pathology and should not be used for soft-tissue evaluation. 4, 5
Do not assume all shoulder weakness is rotator cuff pathology—pain provocation during testing is critical for differentiating rotator cuff tears from cervical spondylotic amyotrophy, which can present with identical weakness patterns. 2
Failure to obtain axillary or scapular Y views can result in missed glenohumeral dislocations that appear normal on AP views alone. 5