Curvature of the crural fascia is different in anterior leg chronic exertional compartment syndrome

Objectives Patients possibly having chronic exertional compartment syndrome of the anterior leg (ant-CECS) require a confirmatory muscle compartment pressure measurement, but this invasive test is patient unfriendly and imprecise. Earlier ultrasound (US) studies suggested that morphology of the leg crural fascia covering the muscle may change in CECS. Aim of this US study was to analyse the curvature of the crural fascia in ant-CECS and healthy controls at rest and following a standard treadmill test. Design Observational. Method From February 2023 till February 2024 ant-CECS patients and healthy controls matched for sex, age and BMI underwent leg imaging with 10 mmHg and 80 mmHg external US probe pressure. The curvature of the fascia was measured before and after a treadmill test using mathematical modelling (extreme convex to extreme concave, +40 to −40). Results A total of 209 US images in 21 ant-CECS patients (13 males; age 31 ± 11; BMI 26 ± 5) who were 1:1 matched with 21 healthy controls (13 males; age 36 ± 14; BMI 24 ± 3) were analysed. With 10 mmHg external pressure, fascia curvature at rest in ant-CECS and controls was not different (ant-CECS 18.6 ± 4.4 vs controls 17.5 ± 6.3, p = 0.53). Thirty seconds and five minutes after exercise, the fascia was more convex in ant-CECS compared to controls (thirty seconds: ant-CECS 26.4 ± 5.8 versus controls 22.8 ± 5.4, p = 0.05; five minutes: ant-CECS 24.3 ± 4.9 versus controls 20.1 ± 5.9, p = 0.02). Curvature changes at 80 mmHg external pressure were not different between groups. Conclusions Following exercise, the crural fascia in patients with ant-CECS is more convex compared to controls.