The diagnostic value of intracompartmental pressure measurement, magnetic resonance imaging, and near-infrared spectroscopy in chronic exertional compartment syndrome: a prospective study in 50 patients.

BACKGROUND: Patients with chronic exertional compartment syndrome have pain during exercise that usually subsides at rest. History and physical examination may raise suspicion of the syndrome; diagnosis is usually confirmed with intracompartmental pressure measurement after exercise. Studies have shown that magnetic resonance imaging and near-infrared spectroscopy have diagnostic ability in this syndrome. HYPOTHESIS: Magnetic resonance imaging and near-infrared spectroscopy can be used to diagnose chronic exertional compartment syndrome. STUDY
DESIGN: Cohort study (diagnosis); Level of evidence, 2.
METHODS: Patients were enrolled if there was clinical suspicion of chronic exertional compartment syndrome, and a fasciotomy was performed based on this suspicion. Before fasciotomy, intracompartmental pressure, near-infrared spectroscopy, and magnetic resonance imaging data were collected during and after exercise on a treadmill. Near-infrared spectroscopy and intracompartmental pressure values were recorded in the same manner after fasciotomy. Retrospective proof that diagnosis of the syndrome had been correct was the absence of exertional complaints from the preoperative examination during exercise at postfasciotomy visit.
RESULTS: Fifty patients (100 legs) participated in the prefasciotomy visit; 3 refused fasciotomy; 2 were lost to follow-up. Of 45 patients who completed the postfasciotomy visit, the diagnosis of chronic exertional compartment syndrome was retrospectively confirmed in 42 patients and discarded in 3 patients. The sensitivity for intracompartmental pressure (cutoff point, 35 mmHg) found in this study was 77% (67%-86%, exact 95% confidence interval), lower than estimates from the literature (93%). The sensitivity (previously defined cutoff) for near-infrared spectroscopy was 85% (76%-92%, exact 95% confidence interval), validating the estimate found in the literature (85%). Sensitivity of magnetic resonance imaging was comparable to that of intracompartmental pressure and near-infrared spectroscopy; associated specificity at a given sensitivity appeared to be lower with magnetic resonance imaging.
CONCLUSION: This study validates the sensitivity of near-infrared spectroscopy and provides estimates for the sensitivity and specificity of magnetic resonance imaging in chronic exertional compartment syndrome in a large group of patients. The sensitivity of noninvasive near-infrared spectroscopy is clinically equivalent to that of invasive intracompartmental pressure measurements.