Acute compartment syndrome: how long before muscle necrosis occurs?

Objectives: Acute compartment syndrome (ACS) is a limb-threatening condition often first diagnosed by emergency physicians. Little is known about the rapidity with which permanent damage may occur. Our objective was to estimate the time to muscle necrosis in patients with ACS.

Methods: This historical cohort analysis of all patients who had a fasciotomy for ACS was conducted in 4 large teaching hospitals. Diagnosis was confirmed clinically or by needle measurement of compartment pressure. Muscle necrosis was determined using pathology reports and surgeons' operative protocols. We used descriptive statistics and estimated tissue survival probability using the Vertex exchange method for interval-censored data.

Results: Between 1989 and 1997 there were 76 cases of ACS. Most cases occurred in young men (median age 32) as a result of a traumatic incident (82%). Forty-nine percent (37/76) of all patients suffered some level of muscle necrosis, and 30% (11/37) of those with necrosis lost more than 25% of the muscle belly. Necrosis occurred in 2 of 4 cases in which the patient had been operated on within 3 hours of the injury, and our exploratory survival analysis estimates that 37% (95% confidence interval, 13%-51%) of all cases of ACS may develop muscle necrosis within 3 hours of the injury.

Conclusions: This is the largest cohort of ACS and the first clinical estimation of time to muscle necrosis ever published. Ischemia from ACS can cause muscle necrosis before the 3-hour period post-trauma that is traditionally considered safe. Further research to identify risk factors associated with the development of early necrosis is necessary.