Skeletal Traction After Orthopaedic Trauma – Subtrochanteric Femur Fractures
By Stephen R. Stephan
Orthopedic Surgery Resident – PGY5
Subtrochanteric femur fractures are defined as proximal femur fractures which occur or extend from the lesser trochanter to up to 5cm distal to the lesser trochanter. They often offer in either young patients undergoing high-energy trauma, such as motor vehicle collisions, or elderly patients with low-energy ground-level falls. Additionally, subtrochanteric femur fractures are also the site of pathologic or atypical fractures, traditionally caused by bisphosphonate use.
Image of subtrochanteric femur fracture – Credits: Orthobullets
The usual workup for patients with a subtrochanteric femur fracture includes a thorough history of present illness, asking specific questions to elaborate on any history of thigh pain prior to the injury. Prior pain may point towards the presence of an atypical or pathologic fracture. Regardless of the mechanism, a thorough history of medication use should be collected. The exam for a patient with a subtrochanteric femur fracture is hip and thigh pain, inability to bear weight, pain with motion, and a likely obvious deformity to the lower extremity. Care should be taken to ensure that there is no skin-tenting and no open fractures, as the deforming forces place the fracture fragments in close proximity to the skin. A thorough neurovascular exam should be done.
Imaging for subtrochanteric femur fractures should include AP and lateral of the hip, AP of the pelvis, and full-length femur films. Oftentimes, a traction view may be used if comminution is present, to identify fracture pieces. The traditional imaging findings for subtrochanteric femur fractures include a proximal fragment that is flexed (iliopsoas), abducted (gluteus medius and minimus), and externally rotated (short external rotators) and a distal fragment that is adducted and shortened (adductors). When looking for signs of a pathologic or atypical fracture, you may see lateral cortical thickening, increased cortical thickness, a transverse or short oblique fracture, medial spike, and/or lack of comminution. In the case of a pathologic or atypical femur fracture, it is imperative to examine the contralateral lower extremity, both during the physical exam and with imaging. Contralateral imaging may show cortical thickening, or a black line in the cortex showing a stress fracture, a sign of impending future fracture.
The usual treatment for subtrochanteric femur fractures is intramedullary nailing via open reduction internal fixation. Usually, patients are not optimized the same day or the operating room is not available until the next day. For this reason, the majority of patients with subtrochanteric femur fractures are placed into skeletal traction in the emergency department or in the ward. Skeletal traction is extremely important because it allows you to maintain length for this very unstable fracture pattern, which is very prone to shortening due to the deforming forces involved. Additionally, in extreme cases, the proximal fragment may be so flexed that it can skin-tent or even become an open fracture. In this case, traction is imperative, and getting to the operating room sooner than later is preferred.
Placing skeletal traction early and correctly provides patients with subtrochanteric femur fractures the best chance at a successful outcome. There are two options as to how to place the skeletal traction – into the distal femur or into the proximal tibia. This is highly surgeon dependent and oftentimes the skeletal traction is continued into the operating room and used to pull traction during the case.
If placing skeletal traction into the distal femur, it is very important to position the traction pin anteriorly in the distal femur. This allows the pin to still be used in the operating room, and it keeps the traction pin away from the intended path of the intramedullary nail. If placing the traction pin into the proximal tibia, the anatomical placement does not interfere with the ultimate fixation. At our institution, we often place a thin K-wire into the distal femur while the patient is in the emergency department or on the ward, then we switch this to a thicker proximal tibia traction pin in the operating room. We feel that the thicker proximal tibia pin can provide more traction and pull if the fracture is extremely shortened. This is, of course, very surgeon dependent and also hospital dependent.
Arbutus Medical SteriTrak® – A skeletal traction pin
Once the traction pin is placed, make sure to secure the bow and protect the patient’s skin, and hang the weights in line with the position and pull off the femur. This will assist with reduction and also make it comfortable for the patient. Post-traction pin X-rays are recommended, as they will show the reduction and also help with operative planning. Steps on placing the distal femur or proximal tibia traction pins can be found in our other blogs.
In summary, subtrochanteric femur fractures are bimodal in their incidence, lead to predictable deformity due to deforming forces, and require surgical fixation. Atypical or pathologic fractures should be high on the differential for low-energy injuries. Skeletal traction is important for these fracture patterns, both pre-operatively and in the operating room to assist with reduction.