A 28-year-old male presents to the emergency department 6 hours after a crush injury to his left leg sustained in a motorcycle accident. He complains of severe pain in the anterior compartment of the leg that is disproportionate to the clinical findings. On examination, the leg is swollen and tense. Pain is elicited on passive dorsiflexion of the foot. Sensation over the dorsum of the foot is intact. Pedal pulses are palpable bilaterally. What is the most appropriate next step in management?

Explanation

## Acute Compartment Syndrome — Immediate Fasciotomy **Key Point:** When clinical features of acute compartment syndrome are unequivocal, **immediate fasciotomy** is the treatment of choice. Compartment pressure measurement is reserved for equivocal or obtunded patients where clinical assessment is unreliable. ### Why This Patient Needs Immediate Fasciotomy This 28-year-old presents with the **classic clinical triad** of acute compartment syndrome following a crush injury: 1. **Pain out of proportion** to the apparent injury — the earliest and most sensitive sign 2. **Pain on passive stretch** — passive dorsiflexion of the foot stretches the anterior compartment muscles, reproducing/worsening pain; this is the most specific clinical sign 3. **Tense, swollen compartment** — indicating elevated intracompartmental pressure **High-Yield:** The presence of intact pulses and sensation does NOT rule out compartment syndrome. Neurovascular compromise (paresthesia, pulselessness, paralysis) are **late findings** indicating irreversible ischemia. Waiting for these signs before acting is a critical error. ### Why Option B Is Incorrect in This Context Compartment pressure measurement (option B) is indicated when: - The patient is **unconscious or uncooperative** (unreliable clinical exam) - The clinical picture is **equivocal** - The patient is **hypotensive** (where the Delta P criterion — fasciotomy when compartment pressure is within 30 mmHg of diastolic BP — is more relevant) When the clinical diagnosis is **clear and unambiguous**, as in this vignette, proceeding to pressure measurement introduces a **dangerous delay**. Per Rockwood & Green's *Fractures in Adults* and the AAOS guidelines, a classic clinical presentation mandates immediate surgical decompression without waiting for confirmatory pressure readings. ### Why Other Options Are Wrong - **Option C (Elevation + ice + serial exam):** Elevation may actually worsen perfusion by reducing arterial inflow. This is contraindicated in established compartment syndrome. - **Option D (MRI):** Imaging is never required to diagnose compartment syndrome and causes unacceptable delay. Compartment syndrome is a **clinical diagnosis**. ### Management Principle ``` Classic clinical signs of compartment syndrome ↓ IMMEDIATE FASCIOTOMY (Do not delay for pressure measurement or imaging) ``` **Clinical Pearl (Harrison's / Rockwood & Green):** The window for fasciotomy is **within 6 hours** of onset to prevent irreversible muscle necrosis and Volkmann's ischemic contracture. This patient is already at the 6-hour mark — further delay is unacceptable. **Warning:** The "30 mmHg threshold" for fasciotomy applies when pressure measurement is being used as the decision tool (e.g., obtunded patient). It does NOT supersede a clear clinical diagnosis requiring immediate surgery.