In a 40-year-old male three days after a motor vehicle collision at 40 mph with airbag deployment, presenting to the emergency department with neck, upper‑back, and right‑knee pain but intact range of motion and sensation, what imaging studies should be ordered?

Imaging Recommendations for Post-MVC Trauma

Order plain radiographs of the right knee (AP and lateral views minimum) immediately; cervical spine imaging is NOT indicated in this patient given the absence of red flag symptoms and intact neurological examination. 1

Right Knee Imaging

Primary Recommendation

• Obtain plain radiographs of the right knee with minimum two views (anteroposterior and lateral) 1
• The lateral view should be obtained with the knee at 25-30 degrees of flexion to evaluate for joint effusion
• Consider adding patellofemoral views if there is focal patellar tenderness

Rationale

The 2020 ACR Appropriateness Criteria for acute knee trauma clearly establishes that radiographs are the first-line imaging modality when Ottawa rule criteria are met 1. Your patient has focal knee pain following significant trauma (40 mph MVC), which warrants initial radiographic evaluation even though ROM is intact. The mechanism (high-speed MVC with airbag deployment) represents significant trauma that justifies imaging regardless of clinical decision rules 1.

If Radiographs Are Negative

• MRI becomes appropriate if there is clinical suspicion for occult fracture or internal derangement (meniscal/ligamentous injury) despite negative radiographs 1
• CT can detect occult fractures with high sensitivity but is less useful for soft tissue injuries 1

Cervical Spine and Upper Back

Primary Recommendation

No cervical spine imaging is indicated at this time 2

Critical Reasoning

The 2024 ACR Appropriateness Criteria for cervical pain explicitly states that in the absence of "red flag" symptoms, radiographs are often not needed in the acute setting and do not influence management or improve clinical outcomes 2. Your patient has:

• Intact range of motion
• Intact sensation
• No neurological deficits mentioned
• Presenting 3 days post-injury (not immediate presentation suggesting instability)

Red Flags That Would Change This Decision

If any of the following were present, imaging would be indicated:

• Neurological deficits (motor weakness, sensory loss, bowel/bladder dysfunction)
• Severe or progressive pain
• Altered mental status
• Concern for vascular injury (vertebral artery dissection can occur even after mild trauma 3, but requires clinical suspicion)
• Inability to assess clinically due to intoxication or other injuries
• Age >65 years (elderly drivers with airbag deployment have elevated risk of hyperextension cervical spine injuries 4)

Important Caveat About Airbag Deployment

While research shows that airbag deployment in restrained drivers can cause hyperextension cervical spine injuries, particularly in elderly patients 4, your 40-year-old patient with intact ROM and sensation does not meet criteria for imaging. However, maintain high clinical suspicion and provide clear return precautions for development of neurological symptoms, as vertebral artery dissection can present in delayed fashion 3.

Clinical Management Points

For the neck/upper back pain:

• Conservative management with NSAIDs and activity modification is appropriate
• Provide explicit return precautions for red flag symptoms
• Consider short-term follow-up (7-10 days) to reassess if symptoms persist or worsen
• MRI cervical spine would become appropriate if red flags develop or pain becomes radicular

Do not order:

• CT cervical spine without contrast (no indication without red flags) 2
• MRI cervical spine as first-line (high rate of incidental findings in asymptomatic patients) 2
• CTA neck (no vascular symptoms present) 2
• Flexion-extension cervical views (no evidence supporting first-line use) 2