Barefoot plantar pressure measurement in Chronic Exertional Compartment Syndrome

Abstract

Patients with Chronic Exertional Compartment Syndrome (CECS) have exercise-limiting pain that subsides at rest. Diagnosis is confirmed by intramuscular compartment pressure (IMCP) measurement. Accompanying CECS, subjective changes to gait (foot slap) are frequently reported by patients. This has not previously been investigated. The aim of this study was to investigate differences in barefoot plantar pressure (BFPP) between CECS cases and asymptomatic controls prior to the onset of painful symptoms. Methods: 40 male military volunteers, 20 with symptoms of CECS and 20 asymptomatic controls were studied. Alternative diagnoses were excluded with rigorous inclusion criteria, magnetic resonance imaging and dynamic IMCP measurement. BFPP was measured during walking and marching. Data were analysed for: Stance Time (ST); foot progression angle (FPA); centre of force; plantarflexion rate after heel strike (IFFC-time); the distribution of pressure under the heel; and, the ratio between inner and outer metatarsal loading. Correlation coefficients of each variable with speed and leg length were calculated followed by ANCOVA or t-test. Receiver operating characteristic (ROC) curves were constructed for IFFC-time. Results: Caseshad shorter ST and IFFC-times than controls. FPA was inversely related to walking speed (WS) in controls only. The area under the ROC curve for IFFC-time ranged from 0.746 (95%CI: 0.636–0.87) to 0.773 (95%CI: 0.671–0.875) representing ‘fair predictive validity’. Conclusion: Patients with CECS have an increased speed of ankle plantarflexion after heel strike that precedes the onset of painful symptoms likely resulting from a mechanical disadvantage of Tibialis Anterior. These findings provide further insight into the pathophysiology of CECS and support further investigation of this non-invasive diagnostic. The predictive value of IFFC-time in the diagnosis of CECS is comparable to post-exercise IMCP but falls short of dynamic IMCP measured during painful symptoms.