Compartment syndrome remains an enigmatic problem. Although every orthopaedist can describe what it is, no one is ever perfectly comfortable with its diagnosis in the clinical setting, and, although it is easy to determine the absence of compartment syndrome, it can be very difficult to identify its presence.
One of the problems in making a diagnosis of compartment syndrome is that its signs and symptoms are often attributable to the underlying injury. "Pain out of proportion" is one of the hallmarks of compartment syndrome. Yet, different patients with a given injury have a wide variation in their complaints of pain. How does one decide if a stated amount of pain is appropriate to the injury or not? How does one decide if pain with movement is due to the associated fracture or to muscle ischemia? Even measurement of intramuscular pressure may be of uncertain value since multiple factors (both the magnitude and duration of elevated intramuscular pressure, the patient's blood pressure, the degree of associated muscle injury, and individual differences in anaerobic threshold) determine the ability of that particular patient to tolerate elevated intramuscular pressure and hence, influence the development of clinically relevant compartment syndrome.
When compartment syndrome is suspected, current clinical practice dictates that immediate fasciotomy be performed. Although this operation carries its own risk of substantial morbidity, the consequences of untreated compartment syndrome may be even more dire. In addition, attempts to study various aspects of compartment syndrome have been difficult. For example, in retrospective studies of patients who underwent fasciotomy, the authors may have assumed that the patients had compartment syndrome. However, unless ischemic muscle was seen, this assumption cannot be proven. Furthermore, if necrotic muscle was found, how does one determine whether the cause was compartment syndrome or direct muscle injury? Similarly, patients who did not undergo fasciotomy may be assumed not to have had compartment syndrome, and any residual muscle or neurologic symptoms are usually attributed to the underlying injury. Finally, when assessing the outcomes of patients with compartment syndrome, how does one decide on the cause or causes of functional deficits? For example, in a patient with a femoral fracture, is knee stiffness due to tethering of the quadriceps at the fracture site, ischemic contracture of the thigh from compartment syndrome, or direct muscle injury?
Given these problems with the definition of compartment syndrome, it is not surprising that we know very little about the outcome of patients with compartment syndrome. The paper by Mithoefer et al. represents the best long-term outcome data that are available regarding the relatively rare compartment syndrome of the thigh. Many of the points made above are exemplified by the findings of this paper. The authors performed chart reviews of patients managed for acute compartment syndrome of the thigh over a ten-year period. Although not directly stated, I would surmise that they used the performance of thigh fasciotomy as their primary case definition. Did they miss cases not treated by fasciotomy? We don't know the answer to this question. Perhaps not all of these cases actually represented compartment syndrome, although the data regarding pressures that the authors present seem compelling. In this study, the authors found that patients with an associated femoral fracture had worse outcomes. Were these worse outcomes attributable to the fracture or the compartment syndrome? Mithoefer et al. suggest that the combination of both may act synergistically, which is reasonable since we know that direct muscle trauma increases the sensitivity of muscle to elevated pressure.
After analyzing their data, the authors make several pertinent points. First, persistent long-term functional deficits were common, although some of these could be attributed to other aspects of the injury. Second, early diagnosis and fasciotomy within eight hours seems critical in order to prevent permanent myoneural damage and associated functional deficits. Because worse outcomes were seen in patients with compartment pressures that were >70 mm Hg, even more urgent fasciotomy is warranted in these instances. The authors confirm that the perfusion pressure of <30 mm Hg is valid for the thigh, which is similar to the criteria established for the lower leg. Further study would help to confirm this. Finally, the authors recommend rehabilitation of the quadriceps in patients with compartment syndrome of the thigh.
Clinicians should remember that compartment syndrome of the thigh, although uncommon, does occur. In a patient with findings that could be due to compartment syndrome, intramuscular pressure should be measured and fasciotomy considered according to the same criteria used for compartment syndrome in the leg. Because of the presence of the circumferential muscular envelope of the thigh, fasciotomy does not carry the same potential complications for the thigh that it does for the tibia. Early fasciotomy may improve outcomes; therefore, the treating surgeon must maintain a high index of suspicion and be ready to treat this complication expeditiously.
*The author did not receive grants or outside funding in support of his research for or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.