Simultaneous intramuscular pressure and surface electromyography measurement in diagnosing the chronic compartment syndrome

We investigated the value of surface electromyography (EMG) as an aid to diagnosing the chronic compartment syndrome (CCS) by detecting elevated intramuscular pressure (IMP) at rest after an exercise test that was caused by remaining muscle contraction. IMP and EMG were measured in the anterior tibial muscle in 37 patients who were suspected to have CCS after an exercise test. At rest after the test, the EMG signal was positive in five of 37 (14%) patients, indicating that patients had remaining muscle contractions that elevated IMP. IMP exceeded 30 mmHg in 16 of 37 patients (43%). In 13 of these 16 patients, the EMG signal was silent, confirming that they had CCS. In the remaining three patients, the EMG signal was initially positive (5-34% of maximal voluntary contraction), and then became silent after communicating with the patients to relax their legs. Only one of the three patients was proven to have CCS. Other reasons for leg pain were diagnosed in 23 patients. The results demonstrated that simultaneous measurements of IMP and EMG differentiate elevated IMP at rest after exercise due to the volumetric load of the compartment muscles seen in patients with CCS and due to the remaining muscle contraction, thereby preventing a false diagnosis of CCS.