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Difficulty: MediumOrthopedic Surgery

A 32-year-old man is evaluated by the surgical team for severe right lower extremity pain. Twelve hours ago, he underwent an uncomplicated open reduction and internal fixation of a comminuted right tibial shaft fracture sustained in a mountain biking accident. The patient reports that over the past two hours, the pain has become agonizing and is no longer relieved by his scheduled doses of intravenous morphine. His temperature is 37.2∘C37.2^\circ\text{C} (99.0∘F99.0^\circ\text{F}), blood pressure is 138/86 mmHg138/86\text{ mmHg}, and heart rate is 112/min112\text{/min}. On physical examination, the right anterolateral leg appears tense and significantly swollen compared to the contralateral limb. The overlying skin is shiny. Passive plantar flexion of the right ankle and toes elicits a dramatic increase in pain. Capillary refill time is 2 seconds, and the dorsalis pedis and posterior tibial pulses are palpable bilaterally. Which of the following is the most appropriate next step in management?

  1. Preparation for immediate fasciotomyAnswer
  2. B
    Observation and escalation of intravenous opioid analgesics
  3. C
    CT angiography of the right lower extremity
  4. D
    Elevation of the right leg above the level of the heart
  5. E
    Initiation of intravenous broad-spectrum antibiotics

Answer

Preparation for immediate fasciotomy
The correct action is to prepare the patient for immediate surgical decompression. The patient's presentation of escalating pain that is out of proportion to the injury, a tense limb, and excruciating pain upon passive stretching of the affected muscles is highly specific for acute compartment syndrome (ACS). ACS occurs when increased pressure within an enclosed fascial space compromises tissue perfusion. The anterior compartment of the lower leg is most commonly affected, particularly following tibial fractures. Crucially, arterial pulses (dorsalis pedis) and capillary refill often remain normal until the latest stages of the syndrome, because the tissue pressure required to cause ischemia is lower than systolic arterial pressure. When the diagnosis is clinically evident, immediate fasciotomy is indicated to prevent irreversible muscle and nerve necrosis.

Step-by-Step Solution

1
Analyze the timeline and presenting symptoms
The patient is 12 hours postoperative from a tibial fracture repair and presents with pain out of proportion to the injury, accompanied by a tense, swollen leg.
Tibial shaft fractures and their surgical repairs are the most common causes of acute compartment syndrome (ACS).
2
Interpret the physical examination findings
Passive plantar flexion stretches the anterior compartment musculature, eliciting severe pain. Pulses and capillary refill remain intact.
Pain on passive stretch is the most sensitive early sign of ACS. Preserved pulses do not rule out the diagnosis, as arterial occlusion is a late and ominous finding.
3
Determine the necessary intervention based on clinical diagnosis
The clinical picture is diagnostic for acute compartment syndrome, requiring emergent surgical decompression.
Delaying treatment for imaging or applying conservative measures in clinically obvious ACS leads to irreversible tissue necrosis within hours.

Key Concept

Acute compartment syndrome is a surgical emergency characterized by pain out of proportion to injury and extreme pain on passive muscle stretch; it requires immediate fasciotomy, and palpable distal pulses do not rule out the diagnosis.
Estimated Time:1m 15s
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Topics

Orthopedic Surgery

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