A patient develops compartment syndrome of the forearm following a supracondylar humerus fracture. The earliest reliable clinical finding that mandates fasciotomy is:
- A Absent radial pulse
- B Skin pallor over the forearm
- C Pain on passive stretch of the fingers (disproportionate to injury) ✓
- D Compartment pressure of >60 mmHg
Explanation
The earliest and most reliable clinical sign of compartment syndrome is pain on passive stretch of muscles within the affected compartment — passively extending the fingers (which stretches the volar forearm flexor muscles) causes severe pain disproportionate to the injury. Other '5 Ps' (pallor, pulselessness, paralysis, paresthesia) are late signs indicating irreversible ischemia. Absent pulse indicates arterial compromise — a late finding. The Delta pressure (diastolic BP – compartment pressure) <30 mmHg is the threshold for fasciotomy, equivalent to compartment pressure typically >30–35 mmHg in a normotensive patient; 60 mmHg is a late threshold. Fasciotomy must be performed urgently before the 6-hour ischemia threshold.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.