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Femoral traction: Evolution, engineering, and systems
Femoral traction: Evolution, engineering, and systems
Since Dr. Hugh Owen Thomas (1834-1891) and his “Thomas Splint,” the topic of femoral traction has been a lesson in engineering evolution. It has also been a study of system inertia, because although at least 6 distinct improvements have been made to the original design, the Thomas Splint is still used in numerous medical facilities around the world. And while the concept of traction has been widely adopted, it is still possible to find dangling weights, bricks or sand bottles as shown below. Even in cutting edge institutions, orthopedists will sometimes opt for traction pins drilled through bone to hang weights, rather than employ the newer traction technologies available today.
Sadly, Dr. Thomas did not live to witness the widespread adoption of his splint by the medical community. It took Dr. Thomas’ nephew, Sir Robert Jones, who cared for numerous femur fractures during World War I, to convince the medical establishment that applying traction to a broken femur just might help.
In retrospect, the concept seems so simple. From a structural standpoint, when a femur is fractured, the surrounding musculature lacks internal scaffolding to resist contraction. Like a guitar with a broken neck, or a crane with a broken boom, there is insufficient structure to resist the contracting force. But unlike a broken guitar neck or crane boom, in the case of a femur fracture, muscle contraction further exacerbates the structural failure. Pain and spasms form a feedback loop, and the solution is to provide temporary external scaffolding.
The frequency of femur fractures is extremely variable depending on setting. For example, the military periodically sends thousands of troops jumping from planes, sometimes all at once. Femur fractures are expected and medics plan accordingly. Training is continuous and the quest for the best medical practices and products is never-ending. In other settings, femur fractures are rare events. Practitioners may spend entire careers never applying traction to a single femur. In such settings traction splints may gather dust for years along with MAST trousers, pelvic binders … and that donut shaped magnet that sits in every ER anxiously awaiting any pacemaker gone astray.
For our readers who rarely encounter femur fractures, but who still hope to be prepared, this writing is for you. And for those of you who care for such injuries on a regular basis, we hope that you too will glean some pearls.
Preoperative diagnosis and treatment
We separate preoperative femur fracture management into three distinct phases: Pre-hospital, emergency department, and in-hospital. Unfortunately, specialists in these three areas do not always resonate. But ideally, the approaches chosen by each optimize care for patients in, and between, all three phases.
Femurs break for a variety of reasons. Some fracture due to compression, for example from sky diving (or rather, after sky diving). Others fracture from torque, perhaps from a caught ski tip. Femurs can snap like tree branches as they wrap around motorcycle handlebars. And they can be blasted apart through penetrating trauma.
For pathologic fractures, the required force may be negligible. Underlying causes for pathologic fracture may include osteoporosis, cancer and infection. Metabolic, medication-related or inborn anomalies may weaken bone as well.
With all types of femur fracture the pain can be immense, and especially so for cases in which the fracture ends are displaced and overlapping. For these, the powerful quadriceps and hamstrings contract virtually unopposed, with intense spasm as the unfortunate result.
First responders often discover patients writhing in pain and simply unable to move. Some patients may be found quite dehydrated having been stranded on the floor for hours. Because the femur is so vascular, it is possible to third-space liters of blood from marrow into the thigh musculature. Hypotensive shock may therefore be present with no sign of external bleeding.
Sometimes patients make the job easy by exclaiming their diagnosis: “I’ve broken my leg… and don’t touch it!” Other times they have underlying comorbidities such as dementia, or concurrent head injuries. Determining the presence of femur injury is hardly challenging. But defining the exact type and location is not simple. Limb shortening and external rotation are strong evidence for femur fracture, while limb shortening and internal rotation suggest hip dislocation. But the location and nature of a fracture or dislocation is rarely certain. In addition, fractures and dislocations may coexist. So treatment for such injuries requires clinical acumen, empathy, finesse… and morphine.
As an aside, regardless of the medical problem, the never-ending debate in the pre-hospital phase is whether to “scoop and run,” vs. treat on scene. Because every scenario is different and transport times may vary widely, the dilemma for responders regarding fractured femurs will probably continue for many years to come. Regardless of protocol, the psychological challenge pre-hospital providers face in treating fractured femurs can be immense. Of course they want to do the best for their patients who may be screaming in agony. But some traction splints lead to far more screaming than others. Combine the screams with the added time to apply traction, the pressure to not donate an expensive piece of equipment to a hospital, and the insecurity that comes with sporadic practice; it makes perfect sense when pre-hospital personnel choose to scoop and run, minus traction.
The act of traction splinting itself can be divided into two parts, traction and splinting. Femoral splinting is easy and can be accomplished with any number of items, the most readily available typically being the uninjured leg. Even for bilateral femur fractures, a great deal of rotational stability may be accomplished simply by wrapping both legs to each other. Useful splinting products for all bones in the body include ACE wraps, Kerlix, towels, sheets, and SAM Splints.
Traction however is the challenge. Many techniques are taught for improvisation in remote, austere settings with sticks, ski poles, paddles and the like. With plenty of time awaiting rescue these techniques are useful.
However the bar is set higher for pre-hospital personnel. Achieving effective traction and stability quickly, with minimal patient movement and pain, is not an easy task. The choice to apply traction or not depends in large part on the pre-hospital provider’s experience, as well as the traction splint available for use.
With or without traction, patients with femur fractures are typically placed on backboards and stretchers. C-collars are often applied as well because fractured femurs are certainly in the realm of “distracting injuries.” Once packaged, patients endure excruciating transports to emergency departments, during which their circulation, sensation and motor function are closely monitored. Pressure points are padded and hopefully pain is controlled with medications and traction readjustments.
On arrival to emergency departments they transition to phase two.
2. Emergency department
Patients with femur fractures are given high priority in emergency departments because they often have concurrent injuries like spine fractures, splenic lacerations, head injuries, etc. They are also at risk for emboli, many are dehydrated, and they may still be experiencing immense pain. On arrival most are left in traction throughout the initial exam. But for a variety of reasons, traction splints are then often removed and replaced with alternative means of stabilization. These are some common reasons to remove traction splints:
- EMS agencies don’t want to lose their expensive equipment. Unlike bicycle share programs in hip cities like Portland and Amsterdam, many medical systems are not yet so refined.
- Emergency physicians need to roll patients to examine their backs, perform rectal exams and to insert Foley catheters. Any splints interfering with these steps must go.
- Bulky traction splints with steel components obscure Xrays and CT images and should be removed.
- Consulting orthopedists often prefer alternative means for splinting.
Orthoglass or plaster are commonly used to replace traction splints in emergency departments. Unfortunately, while these materials make for great splints they offer zero traction. But for the purpose of temporary stabilization through trauma rooms and CT scanners, these options are frequently chosen.
For patients, this transition can be scary and exasperating because they recall the recent pain experienced following injury and with initial splint application. Even for emergency department personnel it may seem absurd to take a patient whose leg is stretched properly, and restart the process.
Ideally patients receive additional analgesia or even femoral nerve blocks prior to this first traction splint transition. Once transitioned, patients are often sent to radiology for further evaluation, and ultimately admitted to either orthopedists or to trauma surgeons for in-hospital treatment.
Lucky patients with femur fractures are sent directly from emergency departments to operating rooms for definitive care. Those with less luck are sent to floor beds where they await treatment. In either case, pain control and minimizing complications are top priorities following admission.
Amazingly, those who transition to floor beds may be resplinted yet again! By this time, most have become morphine sponges.
Orthopedists place some in “Bucks traction” or skin traction. The lower limb is wrapped in protective padding and weights applied as shown here:
Those who are perhaps least lucky have pins drilled through their distal femurs, tibias or calcanei, from which weights are dangled to maintain traction until more definitive operative care may become available. While this step may seem extreme, it limits the risk of developing pressure points, assures lower limb perfusion, and offers physicians the ability to examine and monitor every square inch of skin.
Specialists in all three phases typically do the best for their patients within the constraints of their respective systems. But from a patient’s perspective, the experience can be exasperating and exhausting.
Of note, the goal of traction is not boney realignment. Some will view Xrays to evaluate the quality of their splinting approach. But during all three phases of preoperative femur fracture care, whether involving buddy wrapped legs, or the Thomas Splint, Bucks traction or traction pins; the primary goals of femoral traction are pain reduction, hemorrhage minimization, and maintained perfusion. Additional objectives are limiting risk for emboli and preventing further damage to underlying tissues.
Traction splint evolution
Having covered the general preoperative femur fracture experience, we will now review the evolution of traction splints. Each splint that exists today has its pros and cons. It is our hope that one day a product will be chosen and systems developed that will enable splint application in the pre-hospital setting, and that will be accepted for use all the way to the operating room, thereby eliminating two painful splint transitions.
1. Thomas splint
Thomas splints are comprised of a simple steel rod bent to contain, traction and cradle a leg. Straps are used to support and traction the fractured femur. The following photo demonstrates the Thomas “full ring.” A modified version called the “half ring” is also shown, which eliminates the need to slide the ring up the entire injured leg. Dangled weights are not needed for such splints; this represents the first major advancement in traction splinting. Products introduced since the Thomas Splint have embodied incremental improvements, but Drs. Thomas and Jones deserve full credit for their leap in femur fracture management.