Gaining Traction with Femoral Shaft Fractures

Case:

A 59-year-old female with prolonged bisphosphonate use presents after a mechanical fall with severe pain in her left thigh. Patient reports that after her fall she had immediate pain and difficulty moving her left leg. EMS found the patient on the ground with a left leg that appeared shortened and rotated. They placed a traction splint which resulted in a substantial decrease in her pain. Physical exam in the ED demonstrates marked tenderness over her mid-thigh and a normal neurovascular exam. Imaging was obtained.

Anatomy:

The femur is the longest and most robust bone in the human skeleton. The shaft features a natural anterior bow and has a rough line of bone that runs down the posterior middle-third called the linea aspera. The linea aspera acts as a stabilizing force to counter the anterior bowing of the femur and also serves as an attachment point for various fascial planes and muscles. The muscles of the proximal femur serve to flex and abduct while the muscles of the distal femur provide varus and extension forces. When the femoral shaft is fractured, these opposing muscles spasm and the resulting forces cause pain and substantial deformity to the bone (1).

Fracture Classification:

There are currently two widely accepted classification systems for femoral shaft fractures. The Winquist and Hansen system classifies the fracture on the degree of comminution while the Orthopaedic Trauma Association (OTA) uses a system that describes the pattern of the fracture (2). The OTA classification system is more precise and tends to be more useful when dealing with consultants.

Table 1: OTA Classification system — Table 1: OTA Classification system

Workup:

Femoral shaft fractures in younger patients are typically associated with high-energy mechanisms. It is important to evaluate these patients for other injuries which may be life threatening and more time-sensitive than the femur fracture itself. Fractures in the elderly can result from low-energy insults such as falls (3). If the degree of fracture does not match the mechanism of injury then a pathologic fracture must be suspected (2). When conducting the workup, it is important to remember that ipsilateral femoral neck fractures have a 2-6% incidence with femoral shaft fractures and these are missed 19-31% of the time (3).

As with all musculoskeletal injuries, a full neurovascular exam should be performed to assess for any deficits caused by the fracture.

Imaging should include: AP and lateral views of entire femur, AP and lateral views of ipsilateral hip, AP and lateral views of ipsilateral knee, and an AP view of the pelvis.

Treatment:

After the necessary initial assessments, pain should be controlled through the use of opioids. Benzodiazepines may aid in reducing spasticity of the muscles around the fracture site. If, on initial exam, there is evidence of neurovascular compromise, then reduction of the fracture must be achieved by pulling traction on the injured leg.

Once all of the necessary imaging studies are performed, orthopedics should be consulted for further management. The definitive treatment for a femoral shaft fracture is surgical fixation. However, if immediate surgical intervention is contraindicated, or will be delayed, the fracture is stabilized using mechanical traction (4).

For mechanical traction to be achieved, a traction pin is inserted into the leg and weights are attached via a pulley system. The amount of weight should be approximately 15% of the patient's body weight (2). There are two recognized locations for traction pin insertion in the setting of a femoral shaft fracture. One is at the distal end of the femur, while the other is at the proximal portion of the tibia. The tibial location is often less technically challenging, as anatomical landmarks are easily identifiable. Using the tibial location for the traction is contraindicated in patients with unstable or compromised knee joints.

Ever wonder how to place a traction pin? Well, read on…

Proximal Tibial Traction Pin Placement

While typically performed by an orthopedic surgeon, the steps for traction pin insertion are outlined below. Steps have been adapted from DeFroda, et al. It is important to know that proximal tibial traction pins are inserted from lateral to medial to lessen the risk of damaging the lateral neurovascular bundle.

Step 1: Identify and mark necessary landmarks: patella, patellar tendon, tibial tubercle, joint line and head of the fibula.

Figure 2: Identifying and marking landmarks

Step 2: Mark pin insertion site 1-2 cm distal and 2-3 cm lateral to the tibial tubercle.

Step 3: Prep the field using chlorhexadine or betadine.

Step 4: Anesthetize the insertion site, the exit sites, associated tracts, and periosteum using 1% lidocaine.

Step 5: Incise the skin overlying the insertion site using a scalpel and blunt dissect to the periosteum using a Kelly clamp.

Step 6: Insert the traction pin completely centered on the tibia. The pin may not sit completely perpendicular to the tibia due to the triangular shape of the tibia.

Step 7: The pin is inserted using a drill and the operator should feel the pin go through two cortexes of the tibia. The pin should be advanced until tenting is observed at the exit site. At this time, the exit site should be incised using a scalpel before the pin exits the skin.

Step 8: Proper pin placement should be confirmed with an AP and lateral X-ray of the pin site. This should be done before weights are applied to the pin.

Figure 5: Confirming proper pin placement

Step 9: After pin placement is confirmed, weights totaling 15% of the patient’s body weight should be added to the pin via a rope and pulley system. If a pulley system is not readily available, the weights may be hung over the bed.

Step 10: Once traction is applied, repeat radiographs of the femur should be obtained to evaluate proper reduction.

Figure 8: Evaluating for proper reduction

Case Resolution:

The patient was found to have a class A3 femoral shaft fracture. The patient was placed in traction via a proximal tibial pin and remained in traction until her left femur was surgically fixed via intramedullary nail.

In this case, the patient’s mechanism of injury did not match the degree of fracture. The patient’s history revealed that she had been taking a bisphosphonate for an extended period of time. Radiographs of both her left and right femurs showed diffuse cortical thickening. This pattern of thickening is commonly seen with prolonged bisphosphonate usage and puts patients at risk for low energy fractures (5).

Faculty Reviewer: Dr. Jeffrey Feden

References:

(1) Karadsheh M , Taylor B. "Femoral Shaft Fractures." Orthobullets. Orthobullets.com, 11 Jun 2015. Web. 30 Jul 2016.

(2) Egol K, Koval K, Zuckerman J. "Femoral Shaft." Handbook of Fractures, 5th ed, Wolters Kluwer, 2015, Phildelphia (400-411).

(3) Hak DJ, Mauffrey C, Hake M, Hammerberg EM, Stahel PF. Ipsilateral femoral neck and shaft fractures: current diagnostic and treatment strategies. Orthopedics. 2015 Apr; 38(4):247-51.

(4) DeFroda SF, Gil JA, Born CT. Indications and anatomic landmarks for the application of lower extremity traction: a review. Eur J Trauma Emerg Surg. 2016 Jul; EPub.

(5) Sheibani-Rad S. Femoral fractures following long-term bisphosphonate use. Orthopedics. 2016 Aug; EPub