What is the appropriate evaluation and management for left shoulder pain?

Evaluation and Management of Left Shoulder Pain

Immediate Red Flag Assessment

Begin by ruling out life-threatening causes: assess for cardiac or pulmonary pathology causing referred pain to the left shoulder, fever with joint effusion suggesting septic arthritis, acute neurologic deficits, or acute trauma with suspected fracture or dislocation—all requiring urgent evaluation. 1

• Left-sided shoulder pain specifically warrants consideration of cardiac ischemia or aortic pathology before assuming musculoskeletal etiology 1
• Screen for systemic symptoms including fever, chills, or constitutional symptoms that may indicate septic arthritis 2
• Evaluate for acute neurologic deficits including numbness, tingling, weakness, or radiation down the arm suggesting cervical radiculopathy or nerve compression 2

Initial Imaging Protocol

Obtain plain radiographs immediately as the first imaging study for all patients with shoulder pain, using minimum 3 views: anteroposterior (AP) in internal and external rotation, and either axillary or scapular Y view. 1, 3

• Radiographs must be performed upright because supine positioning underrepresents shoulder malalignment and misses up to 50% of dislocations 3, 2
• The axillary or scapular Y view is mandatory—AP views alone miss up to 50% of glenohumeral and acromioclavicular dislocations 3, 2
• Do not skip initial radiographs even in atraumatic presentations, as osteoporotic fractures can occur with minimal or unrecognized trauma, especially in elderly patients 2

Age-Specific Diagnostic Framework

Patients Under 35-40 Years

Focus your evaluation on glenohumeral instability and labral tears, asking specifically about recurrent subluxation, "dead arm" sensation, mechanical symptoms, or history of dislocation events. 1, 2

• Perform comprehensive instability assessment including apprehension and posterior stress tests 2
• If instability or labral pathology is suspected, MR arthrography is the gold-standard imaging modality, superior to standard MRI 2

Patients Over 35-40 Years

Prioritize rotator cuff disease, degenerative changes, impingement syndrome, and arthritis as the predominant causes. 1, 2

• Rotator cuff tendinopathy/tear presents with pain during overhead activities and weakness, particularly with pushup movements that load the rotator cuff eccentrically 2
• For suspected rotator cuff tears, MRI without contrast or ultrasound are equivalent first-line studies when performed by experienced operators 1, 2
• Pain during abduction between 70-120 degrees suggests supraspinatus impingement under the coracoacromial arch 2

Essential Physical Examination

Assess tone, strength, soft tissue length changes, joint alignment of the shoulder girdle, and range of motion in all planes, with specific provocative maneuvers based on age and presentation. 1

For Rotator Cuff Pathology (Age >35 years):

• Perform empty can test, external rotation strength testing, Hawkins' test (92% sensitive), and Neer's test (88% sensitive) 2
• Focal weakness during abduction with external or internal rotation indicates rotator cuff involvement 2
• Pain with internal rotation and arm behind back specifically implicates subscapularis tendon 2

For Instability (Age <35 years):

• Perform apprehension and relocation tests for anterior instability 2, 4
• Document any sensation of shoulder "giving way" or feeling unstable during activities 2

Critical Distinction:

• Preserved passive range of motion with painful/weak active abduction suggests rotator cuff pathology, while limited and painful passive motion indicates adhesive capsulitis. 2

Advanced Imaging Algorithm

If Fracture Identified:

• Obtain CT without contrast to characterize fracture complexity, displacement, and aid surgical planning 1
• Unstable or significantly displaced fractures require prompt orthopedic referral 2

For Suspected Rotator Cuff Tears (Age >35):

• MRI without contrast or ultrasound (sensitivity 85%, specificity 90%) are equivalent first-line studies 1, 2
• Ultrasound allows dynamic assessment during arm movement and is cost-effective when local expertise available 2

For Suspected Instability or Labral Tears (Age <35):

• MR arthrography is the reference standard in subacute or chronic settings 1, 2
• In acute trauma, MRI without contrast is preferred 1

Initial Conservative Management

Start with NSAIDs (ibuprofen 400-800 mg three to four times daily), complete rest from aggravating activities, and early physical therapy referral focusing on stretching and mobilization. 1, 2

Pharmacologic Management:

• NSAIDs such as ibuprofen 400-800 mg three to four times daily for inflammatory pain 1
• Acetaminophen for pain relief when no contraindications exist 1
• Neuromodulating medications (gabapentin or pregabalin) when neuropathic features present including electric shock sensations, sensory changes, allodynia, or hyperpathia 1
• Intra-articular corticosteroid injections (triamcinolone) for more severe cases 2

Physical Therapy Protocol:

• Complete rest from aggravating activities until asymptomatic 2
• Gentle stretching and mobilization techniques focusing on increasing external rotation and abduction to prevent frozen shoulder 1, 2
• Avoid overhead pulley exercises, which encourage uncontrolled abduction and worsen rotator cuff pathology 2
• Rotator cuff and scapular stabilizer strengthening only after achieving pain-free motion 2
• Consider functional electrical stimulation to improve shoulder lateral rotation 2

Expected Timeline:

• Evidence-based conservative care leads to full recovery in approximately 80% of patients within 3-6 months 2
• Return to activities allowed after completing functional, progressive, individualized program over 1-3 months without symptoms 2

Indications for Orthopedic Referral

Refer urgently for red flag diagnoses (septic arthritis, acute neurologic deficits, fractures requiring fixation), or electively after 3-6 months of failed conservative therapy. 1, 2

• Only approximately 9% of patients with subacromial impingement ultimately require surgical referral after unsuccessful conservative management 2
• Orthopedic referral is premature before a well-managed 3-6-month trial of conservative therapy 2

Critical Pitfalls to Avoid

• Do not dismiss neuropathic symptoms as "normal pain"—they require specific evaluation and treatment with neuromodulating agents rather than just NSAIDs 1
• Do not assume absence of trauma means absence of fracture, especially in elderly patients with osteoporosis 2
• Do not misinterpret shoulder instability pain as impingement, cervical disc disease, or AC joint pathology—this leads to incorrect management 2
• Do not order MR arthrography in acute postoperative settings; standard MRI without contrast is appropriate 1
• For left shoulder pain specifically, always exclude cardiac and pulmonary causes before attributing pain to musculoskeletal pathology 1