What diagnosis is likely for a crunching sound in the shoulder?

Likely Diagnosis for Crunching Sound in Shoulder

A crunching sound in the shoulder most likely indicates subacromial impingement syndrome with associated rotator cuff pathology, subacromial bursitis, or degenerative changes of the acromioclavicular joint. 1, 2, 3

Clinical Context

The "crunching" sound (crepitus) in the shoulder typically represents:

• Subacromial impingement where the rotator cuff tendons and subacromial bursa are compressed between the humeral head and acromion during shoulder movement 2, 3
• Rotator cuff tendinopathy or partial tears with associated inflammation and fibrotic changes that create audible grinding 2, 4
• Acromioclavicular joint arthritis with degenerative changes causing bone-on-bone contact 4, 3
• Calcified coracoacromial ligament contributing to mechanical impingement 4

Diagnostic Approach

Initial Imaging

Plain radiographs should be obtained first to evaluate for:

• Acromial spurs and abnormal acromial morphology 1
• Acromioclavicular joint hypertrophy or arthritis 1, 4
• Calcifications in the rotator cuff or coracoacromial ligament 4
• Standard views include anteroposterior views in internal and external rotation plus an axillary or scapula-Y view 1

Advanced Imaging (if radiographs are noncontributory)

MRI without contrast is the gold standard for soft tissue evaluation with a 9/9 appropriateness rating from the American College of Radiology 5, 1, 6:

• Provides excellent visualization of rotator cuff pathology including tendinosis, partial-thickness tears, and full-thickness tears 5, 6
• Demonstrates subacromial bursal inflammation and thickening 5
• Shows muscle atrophy and fatty infiltration that guide treatment decisions 6

Ultrasound is equally appropriate (9/9 rating) when performed by experienced operators 5, 1, 6:

• Has 90-91% sensitivity and 93-95% specificity for full-thickness rotator cuff tears 1
• Can be performed dynamically to assess impingement during shoulder movement 5
• Limited by operator dependence and reduced accuracy for partial-thickness tears 1

Common Pitfalls

• Do not assume crepitus is benign - it often indicates underlying structural pathology requiring treatment 2, 3
• Radiographs may appear normal despite significant soft tissue pathology, necessitating advanced imaging if symptoms persist 5, 2
• Ten percent of rotator cuff tears are asymptomatic and present only with morphologic changes, so crepitus may be the primary presenting symptom 5

Treatment Implications

The specific diagnosis determines management:

• Conservative treatment (physical therapy, NSAIDs, activity modification) is typically first-line for impingement syndrome and tendinopathy 2, 4
• Steroid injection into the subacromial space may benefit patients with bursitis or impingement 4
• Surgical intervention may be required for refractory cases or when imaging reveals full-thickness rotator cuff tears, particularly in active individuals 2, 7, 3

MRI findings of tendon retraction, muscle atrophy, and fatty infiltration are critical for determining whether conservative versus operative repair is appropriate and predicting postoperative prognosis 5, 6.