What is the appropriate workup and management for a patient presenting with left shoulder pain?

Left Shoulder Pain Workup

Start with standard three-view shoulder radiographs (AP in internal and external rotation plus axillary or scapular-Y view) performed upright, as this is the preferred initial imaging that effectively identifies fractures, dislocations, and malalignment while guiding all subsequent management decisions. 1, 2

Essential History Elements

Document these specific details to guide your diagnostic approach:

Mechanism and Timing:

• Record exact injury mechanism including fall height, landing position, and whether work-related 3
• Distinguish acute (<2 weeks) from chronic (>6 months) presentations 3
• Classify as traumatic (specific event) versus atraumatic 3
• Note prior shoulder dislocations, fractures, or rotator cuff repairs 3

Pain Localization (Critical for Diagnosis):

• Anterior shoulder → suspect rotator cuff or biceps pathology 3
• Superior shoulder → indicates acromioclavicular joint disease 3
• Scapular region → consider cervical spine referred pain or rotator cuff 3

Red Flags Requiring Immediate Attention:

• Fever, chills, or constitutional symptoms suggesting septic arthritis 3
• Neurological symptoms (numbness, tingling, weakness, arm radiation) indicating cervical radiculopathy or nerve compression 3
• Left-sided shoulder pain with thoracic pain, cough, dyspnea, or fever → consider pulmonary pathology including lung neoplasm, pleural infection, or subdiaphragmatic disease referring through the phrenic nerve 4, 5

Age-Specific Focus:

• Over 35-40 years: prioritize rotator cuff disease, degenerative changes, arthritis 3
• Under 35 years: focus on instability, labral tears, sports injuries 3

Initial Imaging Protocol

Standard Radiographs (Always First):

• Three-view series: AP internal rotation, AP external rotation, and axillary lateral or scapular-Y view 1, 2
• Must be performed upright to avoid underrepresenting malalignment 1
• The axillary or scapular-Y view is essential—acromioclavicular and glenohumeral dislocations are frequently missed on AP views alone 1

Advanced Imaging Algorithm (Based on Radiograph Results)

If radiographs are noncontributory, proceed based on clinical suspicion:

For patients <35 years with suspected labral tear/instability:

• MR arthrography is the gold standard (appropriateness rating 9/9) 1
• Superior to standard MRI for intra-articular pathology including labral tears and capsular injuries 1

For suspected rotator cuff pathology:

• MRI without contrast OR ultrasound (both rated 9/9 appropriateness) 1
• Choice depends on local expertise 1
• Standard MRI typically sufficient in patients >35 years where rotator cuff disease predominates 2

For fractures requiring better characterization:

• CT scan provides superior fracture pattern delineation and is valuable for preoperative planning of complex fractures 1

For suspected septic arthritis:

• Ultrasound or fluoroscopic-guided arthrocentesis (rated 9/9) with aspiration and fluid analysis 1, 2

Diagnostic Injections (When Diagnosis Remains Unclear)

Consider targeted injections to establish diagnosis and provide symptom relief:

• Subacromial space injection for subacromial bursitis 6
• Acromioclavicular joint injection for AC arthritis 6
• Intra-articular injection for glenohumeral joint injury 6
• Biceps tendon injection for bicipital tendinitis 6

Critical Pitfall to Avoid

Never assume absence of trauma means absence of fracture—elderly patients with osteoporosis can sustain fractures from minimal or unrecognized trauma 3. Always obtain radiographs in older patients even with seemingly atraumatic presentations.

Immediate Surgical Referral Indications

Refer urgently for:

• Neurological deficits 2
• Unstable or significantly displaced fractures 2
• Shoulder joint instability 2
• Suspected massive rotator cuff tears (expedited repair optimizes outcomes) 2
• Types IV, V, VI acromioclavicular joint injuries 7
• Posterior sternoclavicular dislocations (urgent referral required) 7

Non-Musculoskeletal Causes (Do Not Miss)

When physical examination is negative for mechanical shoulder pathology but pain persists, systematically evaluate:

• Cervical spine pathology: obtain cervical spine radiographs and nerve conduction studies 4
• Thoracic outlet syndrome: perform test maneuvers for brachial plexus compression or subclavian vessel occlusion 4
• Pulmonary/pleural disease: especially with left shoulder pain plus respiratory symptoms, fever, or constitutional symptoms 4, 5