What is the appropriate initial management for acute left shoulder pain without red‑flag features?

Initial Management of Acute Left Shoulder Pain Without Red Flags

Begin with plain radiography of the shoulder as your first-line imaging study, regardless of the suspected etiology of acute shoulder pain 1.

Clinical Assessment Framework

Before ordering imaging, perform a focused evaluation looking for:

• Mechanism of injury (trauma, fall, overhead activity)
• Red flags requiring urgent referral: severe trauma with obvious deformity, neurovascular compromise, suspected infection, or concern for cardiac etiology (left shoulder pain can be referred cardiac pain)
• Specific physical findings that guide next steps: joint instability on examination, inability to actively move the shoulder, or point tenderness over specific structures

Initial Imaging Algorithm

Step 1: Plain Radiographs (Always First)

Order a standard 3-view shoulder series 1:

• Anterior-posterior views in internal and external rotation
• Axillary or scapula-Y view (critical—do not skip this view as it identifies dislocations that AP views miss)

Rationale: Radiographs identify fractures, dislocations, and malalignment—the two primary concerns requiring immediate management decisions 1.

Step 2: If Radiographs Are Normal or Nonspecific

Your next imaging choice depends on clinical suspicion 1:

For suspected occult fracture:

• CT shoulder without IV contrast (best for subtle nondisplaced fractures)
• OR MRI shoulder without IV contrast (detects bone marrow edema and soft tissue injury simultaneously)

For suspected rotator cuff tear:

• MRI shoulder without IV contrast (90-91% sensitivity for full-thickness tears) 1
• OR ultrasound shoulder (equivalent performance to MRI for full-thickness tears, 90-91% sensitivity) 1
• Choose MRI over ultrasound if: large body habitus, restricted range of motion from acute pain, or suspicion of additional intra-articular pathology like labral tears 1

For suspected dislocation/instability on examination:

• MRI shoulder without IV contrast (posttraumatic effusion provides natural contrast for soft tissue visualization) 1

For suspected labral tear:

• MRI shoulder without IV contrast in acute trauma (joint effusion acts as natural contrast) 1

Conservative Management Approach

While awaiting or alongside imaging, initiate 2:

For any duration of shoulder pain:

• Low-level laser therapy
• Multimodal care: heat/cold application, joint mobilization, range of motion exercises
• Cervicothoracic spine manipulation/mobilization if there is associated neck pain or restricted cervicothoracic movement
• Oral NSAIDs or acetaminophen for pain control 3

Do NOT offer 2:

• Ultrasound therapy (not imaging—therapeutic ultrasound)
• Taping
• Interferential current therapy
• Soft tissue massage alone

Critical Pitfalls to Avoid

1. Never skip the axillary or scapula-Y view on initial radiographs—glenohumeral and acromioclavicular dislocations are frequently missed on AP views alone 1

2. Do not order MRI as first-line imaging—radiographs must come first to rule out fracture and dislocation 1

3. Recognize that left shoulder pain can be cardiac in origin—ensure you've excluded acute coronary syndrome before attributing pain solely to musculoskeletal causes

4. Reassess at each visit for worsening symptoms, new neurological findings, or failure to improve, which may warrant specialist referral 2

When to Refer

Urgent orthopedic referral:

• Unstable or significantly displaced fractures on radiographs
• Acute dislocation requiring reduction
• Suspected massive rotator cuff tear (requires expedited surgical timeline for optimal outcomes) 1

Elective referral:

• Persistent symptoms despite 6-8 weeks of conservative management
• Complete rotator cuff tears in active patients
• Recurrent instability

The 2025 ACR Appropriateness Criteria provide the most current, high-quality evidence for this imaging algorithm 1, while the 2021 OPTIMa clinical practice guideline supports the conservative management recommendations 2.