Merriam-Webster defines an emergency as “an unexpected and usually dangerous situation that calls for immediate action.” Most outpatient clinic visits, especially orthopedic outpatient clinic visits, do not fall into this category. Outpatient orthopedic conditions are rarely dangerous and seldom require immediate action, so encountering an orthopedic emergency in an outpatient setting would certainly be “unexpected.” But, it can, and does, happen, and missing an orthopedic emergency can have devastating consequences. This chapter is intended to arm primary care providers with the knowledge they need to identify orthopedic emergencies when they see them and to give them a strategy for dealing with orthopedic emergencies in those rare instances when they might present in an outpatient setting.

Let’s start with two orthopedic emergencies you’ll likely never see outside the emergency room but are common enough to deserve a few lines of explanation in the chapter.

Acute, traumatic toe and (more commonly) finger amputations are injuries you may never see but may well encounter in the form of a panicked phone call from a hysterical patient who hasn’t thought things through enough to just head straight to the nearest emergency room. The instructions for this patient are simple:

1. 
   

   Call 911 and request an ambulance for expedient transport to the nearest emergency department. It is not recommended that these patients drive themselves to the emergency room as blood loss and shock may impair reaction time and judgment or even result in a loss of consciousness.

   
   
2. 
   

   Do not eat or drink anything. If the digit is to be surgically reimplanted, immediate surgery is necessary, and an empty stomach makes general anesthesia much safer.

   
   
3. 
   

   Wrap the amputated digit in a clean, moist cloth and place it in a plastic bag. Seal the bag and place it in a second bag filled with ice. Cooling the amputated part will prolong its viability and increase the odds that the reimplantation will succeed.

Any patient with severe neck or back pain after significant trauma may have an unstable spine. Displacement of an unstable spine can result in spinal cord or nerve root injury and permanent neurologic impairment. “Severe pain” and “significant trauma” are subjective criteria, which can make diagnosing an unstable spine difficult. It is prudent to err on the side of caution. If there is any doubt or if the patient is complaining of neurologic symptoms (numbness, tingling, weakness), the patient should be evaluated in the emergency department with either flexion/extension x-rays or a magnetic resonance imaging (MRI) of the spine.

Post-traumatic compartment syndrome is a rapidly evolving, potentially devastating complication of blunt injury to an extremity. Crush injuries can result in compartment syndrome as well. In the extremities, muscle groups are contained in thick, dense envelopes of fascia called compartments. While this condition can develop in the thighs, arms, and forearms, the fascial compartments are thickest in the legs, so compartment syndrome is most common there. Figure 7-1 shows three separate muscle groups in three individual compartments.

Figure 7-2 shows a schematic representation of the circulatory system of a typical muscle compartment. The compartment, a pink square in the diagram, is bordered by four black lines representing the dense, noncompliant fascial walls that envelope the compartment. The illustration shows a single, large-diameter artery bringing blood into the compartment. Blood entering the compartment through this artery is under relatively high pressure. If the patient’s blood pressure is 120/80 mm Hg, the mean pressure in this artery is 100 mm Hg. Once it enters the compartment, this artery branches into arterioles, which terminate as small-diameter capillaries that are the site of the nutrient and oxygen/carbon dioxide exchange that keep the muscles in the compartment alive. These capillaries combine to form veinules, which coalesce, in this model, into a single, large-diameter vein that allows blood to exit the compartment. The typical pressure inside the compartment is less than 15 mm Hg, and the pressure inside the large-diameter vein is about 3-5 mm Hg. It is the pressure gradient between the high-pressure arterial inflow vessel and the low-pressure venous outflow vessel that drives blood through the compartment.

Blunt or crush trauma that is sufficient to tear the high-pressure vessels on the arterial side but does not lacerate the fascial boundaries of the compartment sets the stage for the development of compartment syndrome. The key is that the trauma is blunt, and that the closed system of the compartment remains intact. Deep lacerations that split open the fascia abolish the closed system of the compartment and make the development of compartment syndrome impossible.

In compartment syndrome, blood from the ruptured, high-pressure artery or arteriole will continue to flow from the injured vessel into the relatively low-pressure compartment space until the pressure inside the compartment reaches that of the arterial blood supply. As the compartment pressure rises, a sequence of devastating consequences ensues. First, the compartment pressure reaches a level high enough to cause collapse of the walls of the low-pressure outflow vessels on the venous side. This results in the stasis of blood flow and muscle tissue ischemia. As the muscle cells in the compartment become ischemic and die, they lyse and release their cytoplasm, resulting in an increase in the osmotic pressure of the extracellular space inside the compartment, favoring the development of even higher compartment pressures. These heightened pressures cause additional injury and death to the muscles, nerves, and other tissues within the compartment. Before long, irreversible tissue damage has occurred, and the extremity is permanently compromised.

Clearly, the most important aspect of the management of compartment syndrome is to recognize and treat the condition before irreversible damage has occurred. A history of high-energy, blunt or crushing trauma may be the most important clue. If you are evaluating a patient who has multiple fractures in a single extremity, like the patient whose x-ray is shown in Figure 7-3, and there is no associated laceration, then you must keep the possibility of compartment syndrome in mind. Other signs and symptoms include (1) pain that is out of proportion to the injury; (2) a firm, swollen, tense extremity; and (3) pain with passive motion of the distal parts.

Testing for pain with passive motion of the distal parts takes advantage of the fact that many of the muscles that control our toes and fingers are located in our legs and forearms, respectively. They move our digits using a system of long, slender tendons, much like the strings that are used to move a string puppet (see the sidebar in Chapter 4, for more details). If you gently flex and extend a patient’s finger or toe, you are alternately pulling on the flexor and extensor tendons and proximal muscle bellies attached to those tendons, causing them to move back and forth in their muscle compartments. If the compartment in which the muscles reside is experiencing compartment syndrome, this will be excruciatingly painful.

Other signs and symptoms of compartment syndrome include the “4 Ps” (pain, pallor, paresthesias, and pulselessness). While these four findings are certainly present in most cases of compartment syndrome, they occur late in the course of the condition. It would be best to make the diagnosis before these findings present so that treatment can be initiated before irreversible tissue damage has occurred.

One tool that can be useful in making the diagnosis early is a compartment pressure-measuring instrument (Figure 7-4). These are commercially available and are standard equipment in most emergency departments. Alternatively, if you are in your office or another location where such an instrument is not available, you can build one yourself using a blood pressure manometer, intravenous tubing, a syringe, and a three-way stopcock (see sidebar).

The pressure should be measured with the needle deep in the muscle of the suspected compartment. A map of the compartments in the leg is shown in Figure 7-5. The pressure in a normal, resting compartment should be less than 15 mm Hg. If the muscles in the compartment have been recently exercised, pressures up to 30 mm Hg are considered normal. Pressures over 45 mm Hg are considered to be diagnostic of compartment syndrome. Patients with compartment pressures between 30 and 45 mm Hg should be monitored carefully. Acute, post-traumatic compartment syndrome evolves quickly. Repeating compartment pressure measurements every 20 minutes for 2 hours should reveal an evolving compartment syndrome.