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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. 1. Pre-hospital 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
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: 1. 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. 2. 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. 3. Bulky traction splints with steel components obscure Xrays and CT images and should be removed. 4. 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.
3. In-hospital 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.
2. Hare splint In the late 1960 s Glenn Hare modified the half ring splint by incorporating a ratchet mechanism, and additional means for length adjustment. The ischial pad was also improved. Most importantly, the Hare traction splint provided a more rapid and effective means to actually stretch a femur fracture. Before the Hare, a variety of straps and other creative ankle hitch tensioning techniques were required. The Hare splint is more compact than the Thomas, as it uses telescoping poles and clamps. Unfortunately the adult version is not compact enough to suit pediatrics, so with the Hare came the first instances of separate pediatric and adult traction splint versions. Today, many EMS services still have protocols that require both pediatric and adult traction splints because of this historical engineering branch point. Many versions of the Hare splint are still available today. 3. Sager splint In the early 1970s Joseph Sager and Dr. Anthony Borshneck developed the Sager splint. Rather than steel rods positioned on either side of the fractured limb, the Sager sits between a patient’s legs, and applies traction from the ankle with counter pressure directed onto the ischial tuberosity.
Hare type splints are problematic when used for proximal femur fractures, because the ischial pad may rest directly under the fracture thereby acting as a fulcrum. The Sager splint solves this problem and may be used for any type of femur fracture without concern for fracture location. The Sager also enables traction for bilateral femur fractures. The Sager also offers ability to measure the actual traction applied. Because of this feature it is now commonly stated that optimal traction is roughly 10-15% of a patient’s body weight (though this estimate may need modification with today’s expanding waistlines). To measure traction force, earlier versions of the splint offered a traction dial, which extended past the foot like the Thomas and Hare. But the most recent Sager is nearly flush with the foot, making it much easier to fit in any type of basket, helicopter or ambulance. The utility and importance of traction quantification, however, remains debatable. Caregivers today monitor pain, perfusion, skin pressure points and stability far more closely than numerical traction metrics. For those of us who live by “treat the patient, not the numbers,” the traction gauge is superfluous. The Sager splint is also sold in pediatric and adult versions. 4. Kendrick Traction Device (KTD) While the Sager was the first monopole splint, the KTD, invented by fire fighter Rick Kendrick in 1986, was the first to move the monopole from medial to lateral leg. For emergency physicians, this greatly improved ease of rolling, rectal examination and Foley insertion. Made from aluminum rather than steel it was the first to claim “relative radiolucency.” It was also the first traction splint to fit every size patient from pediatric to adult.
Interestingly, while 4:1 traction is the theoretical mechanical advantage, the experimental traction provided is still less than 1:1. For 40 pounds of force, the output traction is less than 35 pounds. And for the KTD the output is less than 10 pounds. Never underestimate friction! The CT-6 also offers a single ankle hitch, which fits everything from small limbs to large boots, while the KTD requires a separate boot hitch. b. ITD (Improved Traction Device) Built by Emergency Products and Research , the ITD offers a stronger cinch mechanism than the KTD, but with no mechanical advantage. Like the CT- 6 , the pole sections are made of carbon fiber, and it offers a more padded groin strap. Mid leg straps are labeled. c. OTD (Optimum Traction Device) Made by the same company as the ITD, the OTD and the KTD are virtually equivalent.
d. TTS (Tactical Traction Splint) North American Rescue has built a black KTD-like splint, which also features labeled midleg straps.
6. STS (Slishman Traction Splint) In 2007 the current version of the STS was developed by Dr. Sam Slishman, but was only made available in the US by Rescue Essentials in 2012. Like the KTD and its relatives, it is a compact lateral monopole splint. But the major advantages offered by the STS are these: a. No extension past the foot This is particularly important for tall patients and for tight transports in baskets, helicopters and ambulances. b. Proximal traction All other splints require the rescuer to apply traction distal to the foot. Proximal traction permits rescuers to remain closer to the patient’s head. It also makes traction readjustment easier in tight spaces like helicopters. And it has the side benefit that cooperative and coherent patients are sometimes able to adjust traction to their own fractured femurs to find the position of greatest comfort. Psychologically this is an enormous advantage because patients can control their own pain. With all other splints, the rescuer-patient interaction goes something like: “As traction is applied to your leg, you may feel discomfort, but eventually you will feel better.” With the STS the dynamic shifts: “Let’s apply traction together until you feel maximum pain relief.” Very different.
splints, the midleg straps keep the splint itself from bowing. The STS is far more rigid with negligible bowing. Traction in the STS is delivered by an internal pulley mechanism, which offers traction comparable to the CT- 6. The input force vs output traction has been tested using more than 80 pounds of input force as shown here: (The two data sets represent the difference in traction output, depending on which end of the splint is held fixed. Traction applied to a patient, therefore, is somewhere in between, because both distal and proximal ends of the splint move in actual use.) Other notable traction splints
1. Donway The Donway splint is found mainly in British, Australian and New Zealand markets. It most closely resembles the Hare, with 2 telescoping poles and distal traction from the ankle. It also is made with pediatric and adult versions.
Traction is delivered pneumatically rather than mechanically. Groin padding is improved compared to the Hare, and traction can be monitored numerically through a pressure gauge. For whatever reason, the Donway splint never found its way into US markets. Given recent advances in splinting, the prognosis for the Donway seems poor. 2. Level One Trauma Splint “LOTS” The LOTS is unusual because it employs a carbon fiber rod positioned posterior to the injured leg. It also utilizes a material wrap with Velcro straps to completely splint the leg. Traction is from the foot and, like the KTD, the LOTS utilizes a 1: cinch strap. It is meant to be useful for splinting other types of fractures, and is sold with a pelvic binder as well. For the purpose of splinting any limb injury, the LOTS is an exceptional product. But for traction, it suffers because of the added time for application, and because it limits access to the injured limb. Expense is also a limiting factor.
3. REEL Perhaps the strongest, most “bomb-proof” splint to date, the Reel is also the most expensive. Another variant of the Hare, the Reel features numerous points of articulation enabling position of injury splinting for arms and legs. Fear of exacerbating injuries made the existence of the Reel splint possible years ago. But today pre-hospital providers are more empowered and encouraged to align injuries on scene for transport, thereby greatly diminishing a need for the Reel.
preoperative splint transitions as well. In fact, he claims to have used his splint on many of his own patients with no reported complications. Following the 2010 Haiti earthquake, the STS was applied to more than 7 patients for up to 10 days (only 7 because that’s all he brought.) Apparently his patients were quite willing and able to modify traction on their own limbs. But Dr. Slishman stresses that he is naturally biased and that his patients received “above average” attention. Further study on prolonged application is clearly required. As for application of the STS ankle hitch proximal to the calf, since this is truly possible, it could one day become standard. But given the time it took for the Thomas splint to gain favor, and the fact that it still remains in use today despite numerous significant splint improvements, Dr. Slishman feels that the proximal calf approach could take another century. In the meantime, if you break your femur, first demand morphine. Second, offer to buy the splint. And third, don’t let anyone remove it until the OR!
