What are the clinical signs of compartment syndrome?

Clinical Signs of Compartment Syndrome

Pain out of proportion to the injury is the earliest and most reliable warning sign of acute compartment syndrome (ACS). 1

Early Signs

• Pain out of proportion to injury - the most sensitive early indicator 2, 1
• Pain on passive stretch of the affected muscle compartment - considered highly sensitive for early detection 1
• Increasing firmness/tension of the compartment as intracompartmental pressure rises 2, 1
• Paresthesia (sensory changes) resulting from nerve ischemia 1

Late Signs

• Paralysis (motor deficits) - indicates significant tissue damage has already occurred 2, 1
• Pulselessness - a late sign indicating severe vascular compromise 2, 1
• Pallor - indicates significant disruption to vascularity 2
• Decreased temperature (poikilothermia) - indicates compromised circulation 3

Diagnostic Value of Clinical Signs

• Individual clinical signs have low sensitivity and positive predictive value but high specificity and negative predictive value 2
• Severe pain alone gives only approximately 25% chance of correctly diagnosing ACS 2
• The presence of both severe pain and pain on passive stretch increases positive predictive value to 68% 2
• When pain, pain on passive stretch, and paralysis are all present, positive predictive value reaches 93%, but by this point irreversible muscle ischemia may have already occurred 2
• Palpation of the suspected compartment is unreliable in isolation (sensitivity 54%, specificity 76% in children) 2

High-Risk Populations

• Young men under 35 years with tibial fractures 1
• Patients with fractures, especially tibial shaft fractures 1
• Patients with crush injuries or high-energy trauma 1, 4
• Motorcyclists with lower extremity injuries 4
• Patients with vascular injuries or burns 1
• Patients on anticoagulation 1

Important Pitfalls to Avoid

• Waiting for late signs (pallor, pulselessness, paralysis) before diagnosis can lead to irreversible tissue damage 2, 1
• Relying solely on palpation for diagnosis is unreliable 2
• Missing ACS in patients without fractures - compartment syndrome can occur with soft tissue injuries alone 1
• Delayed diagnosis in obtunded, confused, or uncooperative patients in whom clinical signs may be impossible to elicit 2
• Elevating the limb excessively can further decrease perfusion pressure and worsen ACS 1

Diagnostic Approach

• Maintain high index of suspicion in at-risk patients 1
• Use scoring charts such as that provided by the UK's Royal College of Nursing to maintain awareness 2
• Direct measurement of intracompartmental pressure is indicated when diagnosis remains in doubt, particularly in obtunded patients 2, 1
• Traditional threshold for diagnosis: absolute compartment pressure ≥30 mmHg or differential pressure (diastolic blood pressure - compartment pressure) <30 mmHg 2

Management

• Position the limb at heart level (not elevated) when ACS is suspected 1
• Arrange urgent surgical consultation for fasciotomy when ACS is diagnosed 1, 5
• Fasciotomy is the definitive treatment to prevent tissue necrosis and permanent functional impairment 4, 5

The combination of clinical signs is more valuable than any single sign in diagnosing compartment syndrome. The absence of clinical signs is more accurate in excluding ACS than their presence is in confirming the diagnosis 2. Early recognition and expeditious surgical treatment are essential to prevent permanent disability 6.