Fractures are relatively common orthopedic injuries, and anyone providing primary patient care is likely to encounter them. Although a complete and thorough treatment of this subject would require an entire textbook in and of itself, a chapter explaining the basic principles of fracture care seems appropriate for any textbook that covers office orthopedics.
WHY TREAT FRACTURES?
What are the goals of fracture treatment? What do we aim to accomplish when we treat these injuries? The best way to answer these questions is to imagine what would happen if we left the fracture untreated. Without some form of stabilization, fractures can be excruciatingly painful, and pain control is front and center among the goals of fracture treatment. A splint, a cast, traction, or surgical fixation, all of these options for fracture treatment stabilize the injured skeleton and significantly reduce the pain associated with it. Treating the fracture also reduces the deformity. Most fractures result in some degree of deformity. Sometimes, the deformity is significant; sometimes it is not. If the deformity is significant, leaving it uncorrected would have negative consequences in terms of musculoskeletal function. Furthermore, deformed bones transmit abnormal forces to the joints above and below them, which can cause premature wear of articular cartilage and early arthritis. A primary goal in the treatment of fractures with significant deformity is to correct the deformity so that these adverse consequences can be avoided. Also, it is usually the case that placing the fractured bone fragments in close apposition and then limiting the motion of the fracture increases the chances that the fracture will heal and achieve a bony union. When fractures don’t heal with a solid bony union, we call them nonunions. When they heal, but heal in abnormal alignment, we call them malunions. So, the basic goals of fracture management are to decrease pain, correct deformity, and increase the chances of fracture healing.
One of the oldest treatments for fractured extremities is traction. If you throw a pearl necklace onto the floor, it can come to rest in about any shape or configuration you can imagine. But if you pull the two ends of that necklace in opposite directions, the necklace will automatically assume the shape of a straight line. That is the principle behind the use of traction to treat long-bone extremity fractures. Applying traction to the foot, for example, will pull an angulated fracture of the femur or tibia straight. For decades, extremity fractures, especially those in the tibia and femur, were treated in traction.
Successful fracture treatment requires that we accomplish two things: (1) put the fractured bone(s) in the proper position (a step orthopedists call reducing the fracture or obtaining a reduction) and (2) maintain that reduction until the fracture has healed. Traction is capable of accomplishing both goals, and it was used to do so with good results for a large part of the history of orthopedics. In the 1940s and 1950s, a big part of any orthopedist’s job was to make hospital rounds on a legion of patients who were in the hospital in bed in skeletal traction waiting for their fractures to heal. Hospitals were full of patients like the one shown in Figure 8-A. These fractures take a long time to heal, so a patient’s length of stay was often between 1 and 3 months, an eternity by today’s standards. With the long periods of bed rest that traction required came all of the attendant complications of immobility. Deep venous thrombosis, pulmonary emboli, pneumonia, pressure ulcers, the list goes on and on. These complications forced the evolution of orthopedics to focus on new treatments and procedures that would mobilize patients faster. For the most part, traction was replaced with open reduction/internal fixation operations, or ORIFs. In these procedures, the skin is opened, and the fracture is reduced back into its anatomic alignment. An internal means of fixation (a rod or a plate and screws) is employed to maintain the reduction until the bone has healed. One of the few examples of the use of traction in contemporary orthopedics is the external fixator. Figure 8-B shows an external fixator apparatus being used in the treatment of a distal radius fracture. Two metal pins are drilled through the skin and into the index finger metacarpal bone. A second set of two more pins is drilled through the skin and into the proximal radius. The two pairs of pins are connected with a rigid frame. The length of this frame can be adjusted to increase the distance between the two sets of pins, applying traction to the fracture. An external fixator is essentially a mobile form of local traction.
CAN FRACTURES CAUSE ARTHRITIS?
The answer is yes, absolutely! In the ankle joint, for example, fractures are the leading cause of arthritis. There are four ways in which fractures lead to arthritis in the joints adjacent to them.
Direct injury resulting in the death of the chondrocytes in articular cartilage. If the bone is injured by a force large enough to break it, it is possible that that same force dealt a fatal blow to some of the cartilage cells on the articular surface. When these cells die, the cartilage deteriorates, resulting in post-traumatic arthritis.
Long-bone fractures that heal with angular deformities subject adjacent joints to abnormal forces. The femur shaft fracture shown in Figure 8-C healed with an angular deformity that affects the weight-bearing forces on the knee below it, shifting those forces disproportionately toward the medial side of the joint. As a result, the medial articular cartilage of the knee joint will wear away faster, and the patient may develop bone-on-bone knee joint arthritis. The consequences of angular deformities in long bones are more serious in weight-bearing joints, where the forces are higher. A fracture of the humerus with angular deformity similar to that shown in Figure 8-C would be less likely to result in post-traumatic arthritis of the shoulder joint above or of the elbow joint below because the forces on these non–weight-bearing joints are much lower.
Intra-articular fractures that disrupt the shape of the articular surface of a bone in a joint. Figure 8-15 shows a tibial plateau fracture that has altered the shape of the proximal tibia significantly. Left uncorrected, this deformity will likely heal in this position, resulting in a loss of the normal congruity between the surface of the femur and the surface of the tibia in the joint. The resulting mismatch in the shapes of these bones will accelerate the wear rate of the articular cartilage and can lead to post-traumatic arthritis in the knee joint. The ankle and the knee are particularly susceptible to the post-traumatic arthritis caused by intra-articular fractures because they are weight-bearing joints, and they have a normal range of motion that is limited to a single flexion/extension plane. The hip joint is also a weight-bearing joint, but it is a universal joint that can move in any plane of motion, allowing it to shift its position and better distribute abnormal forces over its articular surfaces.
Fracture healing often increases the density of bone, decreasing its elasticity. Figure 8-D shows a cross section of a typical bone (in this case, the tibia). The image also demonstrates an interesting aspect of the anatomy of our bones. Each bone has a hard, outer shell of dense cortical bone and a soft, inner matrix of porous cancellous bone. In the diaphysis (shaft) of bones like the tibia and femur, the layer of hard cortical bone is very thick. This thick, dense cortical bone is shown by the black arrow in Figure 8-D. At the proximal end of the tibia and the distal end of the femur, the morphology of these bones starts to change. The dense cortical shell becomes paper thin (red arrow), and the bone flares out like the end of a trumpet. These expanded bone ends with relatively thin cortical walls and large volumes of softer, more elastic cancellous bone are thought to provide a shock-absorbing function that helps preserve the knee joint. Many bones are configured this way. Fractures that injure the wide, spongy sections of a bone heal with bone that is typically more dense and less elastic, making those bones less efficient shock absorbers.
There are a handful of terms used to describe fractures that are important to know and understand. These terms and their definitions are reviewed in the material that follows. Until the recent increase in our ability to share x-ray images using social media-based devices, the terms used to accurately describe fractures were critical. These terms helped orthopedic providers conjure up a mental picture of the fracture that was being described to them as they received consults over the phone. These days, providers can quickly and easily share x-rays on smartphones (patient-identifying information excluded, of course). As a result, the ability to accurately describe a fracture is becoming a lost art. When ordering x-rays, always order an anteroposterior (AP) and a lateral view (or two other orthogonal views). Figure 8-1 demonstrates how a broken bone can look perfectly aligned on one view (as the tibia looks on the AP view in Figure 8-1A) and be poorly aligned on the second view (see how angulated the tibia fracture is on the lateral view in Figure 8-1B). The fracture of the distal tip of the fibula also appears to be reasonably well aligned on the AP view, but we can appreciate that it is 100% displaced on the lateral view. If a long bone (like the tibia, femur, or humerus) is being studied, AP and lateral x-rays should include the joints above and below the fracture. This may not be practical in all cases, but strictly speaking, that is the protocol.
In orthopedics, we use the term fracture to describe any injury that disrupts the structure of a bone. For instance, we would consider a tiny “hairline” crack a fracture, and an injury that breaks a bone into two unconnected pieces is also a fracture. Also, we don’t use the term compound fracture. To some, a compound fracture is any severely displaced fracture. To others, the term indicates that the bone has penetrated through the skin. In orthopedics, we have other terms we use to describe these injuries, and we avoid using the term compound fracture because of the confusion it creates. The basic terms used in describing fractures are provided next.
Figure 8-1.
An AP (A), and lateral (B) x-ray of a tibia and fibula (tib-fib) fracture demonstrating how the fracture can appear well aligned on one view and displaced on the other. When getting x-rays to evaluate an injured extremity, it is important to obtain at least two views at 90 degrees (orthogonal) to each other.
The terms intra-articular and extra-articular are used to indicate whether the fracture we are describing enters into an adjacent joint. Figure 8-2 shows an intra-articular fracture of the proximal tibia. The fracture enters the knee joint. The fracture in Figure 8-3 is an extra-articular fracture of the same bone. The fracture shown in Figure 8-3 does not enter the joint.
The terms displaced and nondisplaced help convey how far apart the broken pieces of bone (fracture fragments) are separated from each other or from their normal anatomic position. Technically speaking, all fractures are displaced some amount if we can see the fracture on an x-ray. The tiny radiolucent line that we see when we examine the x-ray of a bone with a hairline fracture is only there because the fracture fragments have separated (displaced) from one and other far enough to create a void, or gap. In living bone, that void is initially filled with blood. Because the density of blood is much less than the density of bone, blood does not block the x-ray beam as well as bone does, so the blood-filled gap appears on the x-ray as a radiolucent line. We generally consider fractures that are displaced a millimeter or two “nondisplaced,” even though they are displaced a small amount. Fractures in which the fragments are separated by a centimeter or more in smaller bones, or several centimeters in larger bones, are described as “widely displaced.” Other terms you will encounter that aim to describe fracture fragment displacement are “moderately displaced” and “minimally displaced.” Obviously, all of this is rather subjective. If you are uncertain how to describe the displacement of a particular fracture, you can always quantitate the displacement in millimeters.
Figure 8-4 shows a fracture of the proximal ulna at the elbow joint. I would estimate that the fracture fragments in Figure 8-4 are displaced about 1 mm. We could either describe this fracture as “an extra-articular fracture of the proximal ulna that is minimally displaced” or “an extra-articular fracture of the proximal ulna that is 1 mm displaced.” If you want to be precise, you can measure the displacement on the x-ray with a ruler, but an estimate will suffice. All that is really important is that we differentiate displaced fractures from those that are minimally or not displaced. Figure 8-5 shows a fracture that is widely displaced, and the femur fracture in Figure 8-6 is extremely displaced.
Figure 8-4.
A minimally displaced (1 mm) fracture of the proximal ulna (see arrow) (Licensed from Shutterstock).
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