Shoulder Pain - Differential Diagnosis
• Subacromial bursitis - Referred pain to lateral upper arm. Impingement signs, painful arc 70°-120° abduction. Overuse; overhead
• Rotator Cuff - Age > 40 yo. Acute=trauma. Chronic=age, acromial spurring, overuse. Tendonopathy, partial or full thickness tears. Pain & weakness, worse w/ overhead reaching, loss of motion. Painful arc, impingement.
• Glenohumeral Arthritis/Adhesive Capsulitis - Aching, stiff; chronic loss of active and passive motion in all planes. OA: crepitus, age > 60 yo. Capsulitis: ↑risk with diabetes, thyroid disease, immobilization, often 40-60 yo.
• Labral Tears & Instability - Young athletes. “Click, pop, catch.” Ant inferior → shot-blocking arm pulled back. Posterior → push-up.
SLAP (Superior Labrum Anterior Posterior) → baseball pitching, throwing, overhead weight lifting.
• AC joint pain - Young: traumatic sprain, fall with separation. Older: AC evolves into OA (can contribute to impingment). Pain, tenderness, possibly swelling over AC joint, positive cross arm test
Shoulder Exam Testing:
• Drop-arm - Rotator cuff tear - Ask patient to abduct arm at 90°. Test is positive if they cannot smoothly adduct shoulder to waist-level.
• Neer - Subacromial impingement, rotator cuff tear or tendonopathy - Fully pronate forearm (thumb pointing backwards) then bring shoulder to full forward flexion. Test is positive if there is any pain.
• Hawkins - Subacromial impingement, rotator cuff tear or tendonopathy - Forward flex shoulder to 90°. Then flex elbow to 90°. Then internally rotate the shoulder. Test is positive if there is pain.
• External rotation - Teres minor & infraspinatus tear or tendonopathy - Flex elbow to 90°. Patient externally rotates the shoulder while examiner provides resistance. Test is positive if there is pain.
• Empty can - Supraspinatus tear or tendonopathy - Forward flex shoulder to 90°. Then internally rotate forearm (thumb points downward). Patient resists examiner’s attempts to push arm downward. Test is positive if there is pain.
Imaging: X-ray if h/o trauma c/f fracture or dislocation, gross deformity, exam c/f RC tear or joint involvement (True AP of glenohumeral joint, axillary lateral, & “Y view” of AC joint). MRI w/o contrast in pts with red flags, R/O acute massive RC tear, previous abnormal radiograph, persistent pain despite 2-3 mos of conservative therapy (e.g. activity avoidance, NSAIDs, PT and home exercises). Partial thickness RC tear: treat like bursitis/tendonopathy/impingement.
#Shoulder #Pain #differential #diagnosis #msk #workup