Baseline compartment pressure measurements in isolated lower extremity fractures without clinical compartment syndrome.

BACKGROUND: The diagnosis of compartment syndrome is most commonly made by clinical examination. Direct compartmental measurements generally serve an adjunctive role in establishing the diagnosis, except when patients have an alteration in mental status. There is little known on what are the expected baseline elevations in compartments after the simple occurrence of a fracture when clinical compartment syndrome does not exist. Knowledge of such measurements might influence the utility of pressure measurements in diagnosing compartment syndrome.

METHODS: A prospective analysis of compartment measurements was performed in 19 isolated lower extremity fractures with the opposite leg as the control. The patients had no clinical evidence of compartment syndrome, had no alteration in mental status, and underwent planned surgical treatment within 48 hours of injury.

RESULTS: Average compartment measurements were 35.5 +/- 13.6 mm Hg (range 10 to 62 mm Hg) in the injured leg versus 16.6 +/- 7.5 mm Hg (range 3 to 40 mm Hg) in the control leg (p = 0.0001). Eighteen patients (95%) had at least one compartment measurement that exceeded a single threshold of 30 mm Hg and 12 patients (63%) exceeded a threshold of 45 mm Hg. Eleven patients (58%) had at least one compartment reading within 20 mm Hg of their diastolic pressure and 16 patients (84%) had one within 30 mm Hg of their diastolic pressure. Ten patients (53%) had a reading within 40 mm Hg of their mean arterial pressure (delta P) and eight patients (42%) had a reading within 30 mm Hg of the mean arterial pressure. No patient developed sequelae or required surgery related to an unrecognized compartment syndrome during a minimum 1-year follow-up.

CONCLUSIONS: Based on our data, use of direct compartment measurements with existing thresholds and formulations to determine the diagnosis of compartment syndrome may not accurately reflect a true existence of the syndrome. A search for other quantitative measures to more accurately reflect the presence of compartment syndrome is warranted.