What are the signs of compartment syndrome or necrosis in a patient with an acute scaphoid fracture?

Signs of Compartment Syndrome or Necrosis in Acute Scaphoid Fracture

While compartment syndrome is exceedingly rare in scaphoid fractures, the primary concern is avascular necrosis of the scaphoid bone itself, not acute compartment syndrome of the hand. However, if you are evaluating for compartment syndrome in the hand or forearm following trauma, here are the critical signs to assess:

Early Warning Signs of Compartment Syndrome

Pain out of proportion to the injury is the earliest and most reliable warning sign of acute compartment syndrome and should trigger immediate evaluation 1. This is considered more significant than the apparent severity of the fracture itself.

Progressive Clinical Signs (in order of appearance):

• Pain on passive stretch of the affected muscle compartment is regarded as the most sensitive early sign of compartment syndrome 2, 1
• Increasing firmness and tension of the compartment occurs as intracompartmental pressure rises 1
• Paresthesias (numbness, tingling) result from nerve ischemia and appear relatively early 1, 3

Late Signs (Indicating Irreversible Damage):

• Paralysis (motor deficits) indicates significant tissue damage has already occurred 2, 1
• Pulselessness, pallor, and decreased temperature are late signs indicating severe vascular compromise 2, 1
• Loss of pulse signifies significant disruption to limb viability 2

Critical pitfall: Waiting for the "5 P's" (pain, pallor, pulselessness, paresthesia, paralysis) means you have already missed the window for preventing irreversible damage 1. Diagnosis must be made before muscle ischemia occurs 2.

Diagnostic Approach

Clinical Assessment Limitations:

• Severe pain alone gives only approximately 25% chance of correctly diagnosing compartment syndrome 2
• When both severe pain AND pain on passive stretch are present, positive predictive value increases to 68% 2
• Palpation of the suspected compartment is unreliable in isolation (sensitivity 54%, specificity 76%) 2
• The absence of clinical signs is more accurate in excluding compartment syndrome than their presence is in making the diagnosis 2

When to Measure Compartment Pressure:

• In obtunded, confused, or uncooperative patients where clinical signs cannot be reliably elicited 2, 1
• When diagnosis remains in doubt despite clinical assessment 1
• Traditional threshold: absolute compartment pressure ≥30 mmHg 2, 1
• Differential pressure threshold: (diastolic BP minus compartment pressure) <30 mmHg 1

Avascular Necrosis of the Scaphoid (The More Relevant Concern)

For acute scaphoid fractures specifically, avascular necrosis of the proximal pole is the primary vascular complication, not compartment syndrome 4, 5.

Signs Suggesting Avascular Necrosis Risk:

• Proximal pole fractures are at highest risk due to retrograde blood supply 5
• Displaced fractures have increased risk of both avascular necrosis and nonunion 5
• Focal decreased radionuclide concentration on bone scan in the proximal pole indicates avascularity 5
• These patients are at high risk of developing nonunion 5

Clinical Examination for Scaphoid Injury:

• Exact location of point tenderness in the anatomic snuffbox 4
• Provocative special tests including Watson's scaphoid shift test 4
• Competent physical examination is essential as fractures may be occult on initial radiographs 4

Immediate Management if Compartment Syndrome Suspected

• Position the limb at heart level (not elevated, as elevation decreases perfusion pressure) 1
• Remove any constricting dressings, casts, or splints immediately 6
• Arrange urgent surgical consultation for fasciotomy when compartment syndrome is diagnosed 1
• Monitor for myoglobinuria and maintain urine output >2 ml/kg/h if rhabdomyolysis develops 1

Time is critical: the longer the duration of elevated tissue pressure, the greater the potential for disastrous sequelae including permanent functional impairment, tissue necrosis, and in severe cases, renal failure 6, 3.