What is the evaluation and treatment approach for a patient with suspected compartment syndrome of the foot?

Evaluation and Management of Foot Compartment Syndrome

When foot compartment syndrome is suspected, immediately remove all constricting dressings or casts, position the limb at heart level, measure compartment pressures in all nine foot compartments if diagnosis is uncertain, and arrange urgent surgical consultation for fasciotomy without delay. 1, 2

Clinical Diagnosis

Primary Warning Signs

• Pain out of proportion to injury is the earliest and most reliable warning sign of acute compartment syndrome 2, 3
• Pain on passive stretch of the affected muscle compartment is the most sensitive early sign 2, 4
• Increasing firmness and tension of the compartment occurs as pressure rises 2

Late Signs (Indicate Irreversible Damage)

• Paresthesias (sensory changes) from nerve ischemia 2
• Paralysis (motor deficits) indicating significant tissue damage 2, 4
• Pulselessness, pallor, and decreased temperature are late signs indicating severe tissue damage 2, 5
• Never wait for these late signs—they indicate irreversible tissue damage has already occurred 1, 2, 5

Diagnostic Limitations

• Clinical signs alone have low sensitivity (~25% with severe pain alone) but high specificity 2
• When pain, pain on passive stretch, and paralysis are all present, positive predictive value reaches 93%, but paralysis indicates irreversible muscle ischemia may have already occurred 2
• Palpation is unreliable (sensitivity 54%, specificity 76%) and should never be used in isolation 1, 2

High-Risk Mechanisms for Foot Compartment Syndrome

• Foot crush injuries 6, 3
• Calcaneal fractures (approximately 10% develop compartment syndrome) 7
• Other foot fractures 6
• Foot surgery 6
• Vascular injury to the foot 6
• High-energy deceleration trauma 4

Compartment Pressure Measurement

When to Measure

• Measure compartment pressures if diagnosis remains in doubt, particularly in obtunded or uncooperative patients who cannot reliably report pain 1, 2
• The foot contains nine compartments—all must be assessed with multi-stick needle catheterization 6, 3
• Use traditional needle manometry, multiparameter monitors, or dedicated transducer-tipped intracompartmental pressure monitors 2

Fasciotomy Thresholds

• Absolute pressure ≥30 mmHg 2, 6, 4
• Differential pressure (diastolic blood pressure minus compartment pressure) ≤30 mmHg 2, 6, 4
• The differential pressure threshold is the most recognized cut-off for intervention in current practice 2

Immediate Management Algorithm

Step 1: Emergency Measures

• Remove all constricting dressings, casts, or splints immediately 1, 2
• Position the limb at heart level (not elevated, as elevation further decreases perfusion pressure) 1, 2, 5
• Arrange urgent surgical consultation for fasciotomy without delay 1, 2

Step 2: Diagnostic Confirmation

• If clinical diagnosis is obvious (pain out of proportion + pain on passive stretch), proceed directly to fasciotomy 2, 3
• If diagnosis is uncertain or patient is obtunded, measure compartment pressures in all nine foot compartments before proceeding 2, 6, 3
• Do not order imaging studies that delay surgical intervention 2

Step 3: Definitive Treatment

• Immediate fasciotomy of all involved compartments is the only effective treatment when compartment syndrome is diagnosed 1, 5, 4
• Use two dorsal incisions for access to forefoot compartments 6
• Use one medial incision for decompression of the calcaneal, medial, superficial, and lateral compartments 6
• Fasciotomy must decompress all involved compartments to prevent ongoing tissue damage 5

Post-Fasciotomy Management

• Monitor for myoglobinuria and maintain urine output >2 ml/kg/h if myoglobinuria develops 1, 5
• Consider early delayed primary closure if minimal tissue bulge is noted after fasciotomy or resolves with systemic diuresis and leg elevation 1, 5
• Use negative pressure wound therapy to reduce discomfort and facilitate closure in patients not candidates for delayed primary closure 1, 5
• Provide diligent wound care to mitigate complications (infection, nerve injury, dysesthesia) 1, 5
• Monitor for compartment syndrome recurrence, particularly in severe cases 1, 5

Critical Pitfalls to Avoid

• Never wait for late signs (pulselessness, pallor, paralysis)—these indicate significant irreversible tissue damage 1, 2, 5
• Never rely solely on palpation for diagnosis (sensitivity 54%, specificity 76%) 1, 2
• Never elevate the limb excessively—this further decreases perfusion pressure and worsens compartment syndrome 1, 2, 5
• Never delay diagnosis in obtunded patients—measure compartment pressures earlier in these populations 1, 2, 5
• Never miss compartment syndrome in patients without fractures—it can occur with soft tissue injuries alone 1, 2, 5

Long-Term Sequelae if Untreated

• Clawing of the lesser toes 7
• Contractures and fixed deformities 6, 4, 7
• Chronic pain and stiffness 7
• Motor weakness and paralysis 6, 4
• Sensory neuropathy 6, 4
• In severe cases, amputation may be necessary 4

Special Considerations for Diabetic Foot Infections

• Urgent surgical consultation should be obtained in cases of moderate or severe diabetic foot infection complicated by compartment syndrome 8
• Consider performing early (within 24-48 hours) surgery combined with antibiotics for moderate and severe diabetic foot infections to remove infected and necrotic tissue 8