The femur is the longest and strongest bone of the body, and it carries the principal weight of the entire body. It is the heaviest tubular bone of the body that requires high-energy force to fracture, for example, as from motor vehicle accidents. Fracture of the femur carries high-risk complications like hemorrhage, fat embolism, and infection. Inappropriate management of femur fracture can also cause prolonged morbidity with shortening, misalignment, and deep venous thrombosis (DVT). The annual incidence of midshaft femur fracture is approximately 10 per 100,000 person-years. Femur diaphysis fracture follows a bimodal distribution that peeks in teenagers and the elderly, as it usually occurs with a high-speed injury in teenagers and with low-speed injuries, such as falls, in elderly with osteopenia or osteoporosis. Paradoxically, long-term use of bisphosphonates has been associated with increased risk of femur fractures, yet it may have confounding factors such as bisphosphonate drug holidays. Emergency medical service (EMS) personnel should splint the femur in the position it is found to prevent further injury during transport. If the neurovascular damage is obvious, the femur should be reduced at the scene. A traction splint is recommended on all mid-shaft femur fractures to establish patient comfort, better fracture alignment, and improved blood flow. It can be used for both closed and open fractures of the femoral diaphysis. Traction splint is designed to provide temporary stabilization at the scene for transport to the definitive treatment/management. Prolonged use of traction splint can cause pressure sores.
Diaphysis of femur starts from lesser trochanter and ends at the beginning of femoral condyles. The anterior side is convex while the posterior side is concave with mild arch giving the flexibility to withhold weight and force from walking, running, and jumping. Anterior muscles that help with hip flexion are iliopsoas, sartorius, and iliopsoas, while quadriceps extend the knee. Medial muscles that adduct the femur are gracilis, pectineus, adductor longus, brevis, and magnus. Posterior muscles include bicep femoris, semitendinosus, and semimembranosus for flexion of the knee. All of these powerful and large muscles lead to displacement and angulation of the femur upon fracture. These large muscles protect the sciatic nerve and femoral nerve from damage, making neurologic injury from isolated femur fracture rare. Vascular supply mainly comes from profunda femoral artery that travels medially to the femur. Arteria nutricia, also known as a nutrient artery, supplies endosteal circulation. The thigh has a space that can hold up to 3 liters of hemorrhageod blood.
A suspected or obvious isolated fracture of the midshaft femur is an indication for traction splint. If there are other fractures in the pelvis, knee, ankle, or foot, the traction is not effective, because traction splints require intact bone support on strap sites to be able to apply traction.
Clinical diagnosis is usually obvious with mechanism, pain, swelling, and deformity/shortening of the thigh. Extreme pain may mask these secondary injuries. Since most of the femur fracture occurs with high energy trauma, pelvic ring, hip, groin, perineum, and buttock evaluations are crucial. Up to 40% of the femur fractures are associated with an ipsilateral knee injury.
Distal pulses (popliteal, dorsalis pedis, posterior tibialis) should be assessed with capillary refills on the ipsilateral toenails. Although neurologic injury with isolated femoral diaphysis fracture is rare as mentioned above, a careful motor and sensory assessments are important.
Commonly used tractions are Thomas, Hare, Sager, Kendrick, CT-6, Donway, and Slishman traction splints. We will discuss the most common Traction splints: Hare, Sager
Hare Traction Splints
In the 1960s, Glen Hare developed Hare traction splint, modifying full ring Thomas splint into half ring splint by incorporating a ratchet mechanism with additional length adjustment mechanisms and improving the ischial pad. It maintained bipolar traction with 2 steel rods on both sides of the limb. Most importantly, the Hare traction splint was more compact, easy, and effective for a femur fracture. The Hare splint is not effective with proximal femur shaft fracture because the ischial pad may rest directly under the fracture. An adult unit cannot be adjusted for pediatric patients. Below is a simplified application guide.
Sager Traction Splints
In the 1970s, Joseph Sager and Dr. Anthony Borshneck developed the Sager splint. Sager traction is unipolar traction. One steel rod sits between a patient’s legs and applies traction from the ankle with counter pressure directed onto the ischial tuberosity. Sager splint sits between the leg against the ischial tuberosity, so it is more effective for proximal femur fracture than hare splint. Also, one Sager splint can be used for a bilateral femur fracture. However, there is increased the risk of damage to the genitalia as the splint can move from the initial ischial tuberosity placement during transport. Sager traction splint can measure the actual traction applied on the gauge. The optimal traction is roughly 10% to 15% of a patient’s body weight.
Traction splint is a good emergency tool to align the femur fracture better, increase arterial blood flow, decrease pain and spasm, and decrease the risk of further injury from fractured bone fragments.
If the patient is not stable, do not waste time trying to apply traction splint at the scene. Splint the injured leg against the uninjured leg to expedite the transport.
If the patient is unconscious, apply traction until the injured and uninjured legs are equal in length.
Make sure it is isolated femur fracture.
Frequently re-assess neurovascular function of the extremity after application of splint and during transport.