Chronic exertional compartment syndrome of the forearm in motocross racers: findings on MRI.

INTRODUCTION: The purpose of this prospective study was to demonstrate the findings of MRI in motocross racers with chronic exertional compartment syndrome (CECS) of the forearm.

MATERIALS AND METHODS: Racers with proven CECS and without CECS and male individuals not involved in strenuous activities with the forearm were included. Signal intensity (SI) and signal-to-noise ratio (SNR) obtained before and after exercise were compared (D-SNR).

RESULTS: Magnetic resonance imaging after exercise showed an increase in SI and SNR in the muscles on T2-WI. The SI increase was obvious in the flexor digitorum superficialis (FDS) and profundus (FDP) in all CECS patients. In addition, a minor SI and SNR increase in the extensor carpi radialis longus (ECRL) was noted. In the non-symptomatic group of motocross racers, there was only a minor increase in SI and the SNR, which was similar in the FDP and ECRL muscles. In the untrained individuals a remarkable increase in the SI and SNR of the FDS/FDP-ECRL was noted. This increased SI and SNR was not present in the majority of non-symptomatic racers.

CONCLUSION: Post-exertional MRI produces significant findings in CECS of the forearm. The motocross racers without post-exertional oedema in the FDP/FDS had no CECS.