Diagnosing Acute Compartment Syndrome

Are Current Textbooks Misleading?

Amir Oron, MD; Niv Netzer, MD; Philip Rosinsky, MD; Danielle Elmaliache; Peleg Ben-Galim, MD


Curr Orthop Pract. 2018;29(6):527-529. 

In This Article

Abstract and Introduction


Background: Prompt diagnosis of acute compartment syndrome (ACS) is critical when trying to prevent irreversible limb damage. Pain out of proportion and pain on passive tendon stretching are sufficient clinical indicators of ACS. Primary care physicians may delay in making the diagnosis of ACS because they may rely on the classic "5 P" signs. However, paralysis and pulselessness will not appear until the later stages of ACS, at a time when irreversible damage has occurred. The aim of this study was to evaluate the guidelines for diagnosis of ACS as perceived by graduating medical students and primary care physicians and as published in textbooks.

Methods: One hundred and seventeen medical students and primary care physicians were questioned as to the diagnostic criteria of ACS. Eleven medical textbooks were reviewed to evaluate the diagnostic approach to ACS.

Results: Of the 117 participants, only 29 (24.8%) answered correctly. Of eleven textbooks, three specifically mentioned the classic "5 P" signs but still provided the correct diagnostic steps, including the essential elements of pain beyond proportion and pain upon passive tendon stretching. Disappointingly, seven textbooks made no mention of the potentially life and limb-threatening diagnosis of ACS, and only one textbook outlined the path to diagnosis of ACS with no mention of the "5 P" signs.

Conclusions: The misguided diagnosis according to the "5 P" signs in nonorthopaedic medical textbooks that clinicians in multiple disciplines depend on may result in devastating consequences. Pulselessness, paresthesia, and paralysis are signs that appear too late in the course of the disease to serve as diagnostic signs and are not signs to be waited for, a point to be emphasized in teaching.


Acute compartment syndrome (ACS) occurs when fascial compartment pressures exceed perfusion pressure due to an increase in the compartment contents, leading to irreversible tissue ischemia and necrosis.[1] ACS is mistakenly presented in medical textbooks and manuals as a straightforward "5 P" diagnosis (pallor, pulselessness, paresthesia, paralysis, and pain).[2–4] However, the diagnosis is clinical and based on two important signs and symptoms: pain out of proportion (POP) to the injury and pain on passive tendon stretching (PPS),[5] definitive indicators of ischemia of the limb.

After prompt diagnosis of ACS, an emergency fasciotomy, including release of all fascial and epimysial envelopes, should take place to relieve pressure buildup and allow tissue perfusion, preventing devastating consequences.[6] Misdiagnosis may lead to catastrophic complications, such as Volkmann ischemic contracture, neurologic deficit, infection, ischemic necrosis of muscles, nerve injury, and loss of a limb.[4] In the late stages of ACS when ischemia and necrosis set in, treatment with surgical fasciotomy and decompression actually is contraindicated, since severe infections might occur in the necrotic muscle, thus causing further damage.[7] Patients at these late stages, with no muscle function of the limb, require supportive care for myoglobinuria and splinting to maintain a functional position.[5]

ACS is most commonly seen after injuries to the leg and forearm, but it may also occur in any limb or organ and is seen by physicians in all medical and surgical disciplines. ACS is commonly seen after crush injuries, fractures, internal bleeding, intraarterial or paravenous injections of drugs, recreational drug abuse, prolonged external compression, ischemic reperfusion injuries, burns, excessive exercise, snakebites, or prolonged malpositioning during surgery.[8,9]

A misguided diagnosis according to the "5 P" signs may be due to the critical difference between microcirculation and macrocirculation of a limb. While the classic signs are indeed important descriptors of acute major arterial occlusion, they are not the initial signs associated with ACS, which jeopardize microcirculation. Major arterial occlusion occurs when an embolic thrombus occludes the femoral or popliteal arteries and results in acute ischemia of the entire limb and all its tissues at once.[10] In contrast, ACS occurs when intracompartmental pressures slowly rise above that of the small end arterioles and lymphatic vessels, depriving the leg of venous drainage. This, in turn, increases intracompartmental pressure, which leads to gradual and slow ischemia of the distal tissues adjacent to the smallest vessels, first by gradually becoming ischemic, and later becoming necrotic. Notably, major arterial blood flow continues for hours, even while the tissues are becoming ischemic.[5]

The purpose of the current study was to evaluate the guidelines for the diagnosis of ACS as perceived by graduating medical students and primary care physicians and as published in traditional medical textbooks.