A 28-year-old male presents to the emergency department 6 hours after a crush injury to his right leg sustained in a motor vehicle accident. On examination, he has severe pain out of proportion to the clinical findings, pain on passive stretching of the foot, and tense swelling of the anterior tibial compartment. Sensation is intact and dorsalis pedis pulse is palpable. What is the most appropriate next step in management?

Explanation

## Diagnosis and Rationale **Key Point:** Acute compartment syndrome with classic clinical signs in a conscious, cooperative patient is a surgical emergency requiring **immediate fasciotomy** — compartment pressure measurement is NOT required before proceeding and should not delay definitive treatment. ## Clinical Features of Compartment Syndrome The classic presentation includes the **5 P's**: | Feature | Timing | Clinical Significance | | --- | --- | --- | | **Pain** (out of proportion) | Early & most sensitive | Present before other signs | | **Pressure** (tense compartment) | Early | Objective finding | | **Paresthesia** | Intermediate | Nerve ischemia | | **Pallor** | Late | Vascular compromise | | **Pulselessness** | Very late | Irreversible damage | **High-Yield:** Pain with passive stretch of muscles in the affected compartment is the single most sensitive clinical sign. This patient has **three cardinal signs**: pain out of proportion, pain on passive stretch, and tense compartment swelling — this constitutes a clinical diagnosis of compartment syndrome. ## Management Algorithm In a **conscious, cooperative patient** with clear clinical signs of compartment syndrome, the standard of care per Rockwood & Green's Fractures in Adults and Campbell's Operative Orthopaedics is: > **Immediate fasciotomy without waiting for compartment pressure measurement.** Compartment pressure measurement is reserved for: - Unconscious or sedated patients - Patients with altered mental status (polytrauma, intoxication) - Equivocal or borderline clinical findings - Patients who cannot reliably report pain (e.g., spinal cord injury) ## Why Option B Is Incorrect Here The stem describes a **conscious, cooperative 28-year-old** with **unequivocal clinical signs**. Delaying fasciotomy to measure compartment pressure in this scenario: - Wastes critical time (irreversible muscle necrosis begins within 6–8 hours of ischemia) - Is not the standard of care for a clinically obvious diagnosis - Risks permanent neuromuscular damage **Clinical Pearl (Harrison's / Campbell's):** Every 30-minute delay in fasciotomy after clinical diagnosis increases the risk of permanent functional deficit. The window for complete recovery narrows rapidly after 6 hours of ischemia — this patient is already at the 6-hour mark. ## Compartment Pressure Thresholds (for reference) When measurement IS indicated: - Absolute pressure **≥30 mmHg** (Whitesides criterion) OR **≥40 mmHg** (some high-volume trauma centers) - **Delta P ≤30 mmHg** (diastolic BP minus compartment pressure) — most widely accepted threshold ## Why Other Options Are Wrong - **C (Elevation + ice + monitoring):** Elevation reduces perfusion pressure and worsens ischemia in compartment syndrome — contraindicated. - **D (Mannitol + fluids):** No role as primary treatment; may be adjunctive in rhabdomyolysis but does not decompress the compartment. [cite: Campbell's Operative Orthopaedics, 14th ed.; Rockwood & Green's Fractures in Adults, 9th ed., Ch. 1]