Chronic exertional compartment syndrome (CECS) is a debilitating disorder affecting mostly an active population. The proposed pathophysiology is increased pressure in muscle compartments causing pain, paresthesia, and inability to tolerate exercise in the affected fascial compartment. CECS involves the lower extremities, primarily affects young active adults, and limits running and/or endurance activities. While the incidence of CECS in the general population is unknown, the prevalence in the military population has been found to be 0.49 cases per 1000 patient-years.
The current standard for definitive treatment of CECS is surgical fasciotomy of the involved compartments. According to a 2016 systematic review, surgical intervention for CECS is successful in only 66% of those affected, with 13% of patients reporting complications from surgery, and 6% needing a repeat procedure. A 2014 retrospective review of military members showed that only 59% of patients who underwent elective fasciotomy for CECS were able to return to full duty while 22% of the patients that were treated with fasciotomy were eventually medically discharged. One of the reasons for the limited success rate, is an incomplete understanding of the pathophysiology coupled with proper patient selection.
Gait retraining is an attractive alternative to fasciotomy. It aims to influence the effect of foot contact and running kinematics to reduce leg compartment pressures which relieves pain. Diebal et al. published a case series of 10 military members with CECS who underwent a gait retraining program that emphasized forefoot running. At six-weeks and one-year post-intervention, running distance, pain, and performance all significantly improved. Despite high rates of success in limited case studies, real world application of gait retraining has limitations. Many patients struggle to make and/or sustain adaptations in their running style. Some patients have severe pain with exercise which limits efforts at effective gait re-training.
A newer proposed treatment is the intramuscular administration of onabotulinumtoxin A, also known as botulinum toxin A or BoNT-A into the muscles of the involved compartment(s). One case series studying botulinum toxin injections for CECS demonstrated normalized intramuscular pressure up to nine months post-injection in 87.5% (14/16) of patients, and exertional pain was completely eliminated in 94% (15/16) of patients. Eleven patients experienced reduced muscle strength that was without functional consequences and transient, with only 1 of the 16 patients who complained of new posterior leg pain that did not appear to be related to BoNT-A injections. There were no other adverse effects reported.
Military sports medicine clinics at Fort Belvoir Community Hospital (FBCH) and USU have been utilizing BoNT-A injections for the non-surgical treatment of CECS. A retrospective review of patients with CECS treated with BoNT-A at FBCH Sports Medicine Clinic from 2014 to 2017 provided data on twenty-nine patients who were treated with BoNT-A for CECS. Prior to treatment, none of the 29 patients were able to perform their desired activity and 24% were unable to run one mile without severe leg pain. After botulinum injections, these numbers improved to 66% and 72% respectively. Sixty-nine percent of patients reported that they were satisfied or somewhat satisfied with their treatment, twelve patients continued to have sustained relief by the time they were contacted, and seven patients experienced a recurrence of symptoms. In those with recurrence, the mean duration of improvement was 7.8 months. Of note,11 patients received both BoNT-A and fasciotomy during their treatment course. Only one patient reported a favorable response to fasciotomy and failure with BoNT-A, suggesting that BoNT-A injections might be predictive of success with fasciotomy.
BoNT-A is FDA approved for intramuscular, intradetrusor, or intradermal use for muscle spasticity, migraine headaches, detrusor instability and severe forehead lines, lateral canthal lines, and glabellar lines in adults. To avoid side effects and predict treatment success, a recently published case review of pre-treatment with xylocaine injections prior to proposed BoNT-A injection for frontalis and glabellar rhytides was issued. Further, a yet unpublished case using the pre-treatment xylocaine protocol was conducted at FBCH. The subject improved her running symptoms with the xylocaine injection and subsequently underwent BoNT-A treatment. One month after the BoNT-A she is able to now walk/run up to 1 mile with no exertional symptoms.
The purpose of this grant application is to create a registry across all MTFs for CECS to compare diagnostic and therapeutic data. We will simultaneously assess the effectiveness of non-surgical treatments options for chronic exertional compartment syndrome as well as test the use of xylocaine injections to predict success for non-surgical or surgical options at selected sites. This study will also determine if successful gait retraining, either home based or supervised, is essential to positive results Furthermore this study will also determine if BoNT-A injections plus gait retraining is better than either treatment alone. Finally, this study would determine if xylocaine injections could predict who will benefit from BoNT-A injections or fasciotomy.