Orthopedic Teaching Cases 2023, Jan, 20 | 12:00 am

Association of femoral shaft and neck fractures

A 38-year-old male struck by a motor vehicle while crossing the street presented to the ED with a blood pressure of 156/92, an HR of 112, a lactate of 0.8, and Glasgow Coma Scale of 15. He was complaining of severe pain in his left lower extremity. He has brisk dorsalis pedis and posterior tibial pulses bilaterally. He has normal rectal tone and no spinal tenderness. His pelvic examination is stable to compression. He has pain over his left femur and left hip. An AP pelvis, an AP internal rotation view of the left hip, and left femur films were obtained displaying a transverse midshaft femur fracture (Fig. 6–41). After confirming the midshaft femur fracture with radiographs, a CT pelvis with 2-mm cuts through the femoral necks

was obtained.

 

 

 

Figure 6–41

 

What is the incidence of concomitant extremity injury following a traumatic femoral shaft fracture?

  1. 10% rate of contralateral distal femur fracture

  2. 15% rate of ipsilateral femoral neck fracture

  3. 15% rate of ipsilateral distal femur fracture

  4. 5% rate of ipsilateral femoral neck fracture

  5. 5% rate of contralateral femoral neck fracture

 

Discussion

The correct answer is (D). Concomitant proximal femur fractures occur in less than 10% of femoral shaft fracture cases. Furthermore, when they do occur, they are missed in up to 30% of cases. As such, it is necessary to critically evaluate the femoral neck in all cases of femoral shaft fractures in order to fully evaluate the patient’s injury patterns and corresponding treatment plan.

What additional intraoperative imaging should be obtained prior to surgery to fully evaluate for the presence of concomitant injuries prior to femoral shaft fixation?

  1. Inlet/outlet pelvic views

  2. Stress radiographs of knee

  3. Judet views of pelvis

  4. Traction views of proximal femur

  5. Lateral of femoral neck

 

Discussion

The correct answer is (E). Concomitant femoral shaft and neck fractures are missed in up to 30% of cases due to the insensitivity of conventional imaging. As such, the femoral neck must be closely evaluated as this injury will dictate fracture fixation order and implant choice. Tornetta et al. have proposed a diagnostic algorithm consisting of an AP internal rotation view of the femoral neck, 2-mm fine-cut computed tomographic scan through the femoral neck, an intraoperative fluoroscopic lateral of the ipsilateral femoral neck prior to fixation, and AP/lateral hip radiographs following fracture fixation prior to waking the patient. This algorithm was found to decrease the incidence of missed femoral neck fractures by 91%.

If the patient is found to have a nondisplaced, ipsilateral femoral neck fracture on additional intraoperative imaging, what is the best order and method of surgical fixation of these fractures?

  1. Open reduction and cephalomedullary nail fixation for treatment of femoral neck and shaft fractures

  2. Closed reduction femoral neck with percutaneous screw fixation followed by retrograde intramedullary femoral nail for shaft fracture

  3. Open reduction of femoral neck fracture with screw fixation followed by retrograde femoral nailing

  4. Antegrade intramedullary nailing of femoral shaft followed by open reduction and percutaneous screw fixation of femoral neck

  5. Open reduction and internal fixation using sliding hip screw of femoral neck fracture followed by open reduction and internal fixation using 4.5-mm LCDC plate for femoral shaft fracture

Discussion

The correct answer is (B). The order of ipsilateral femoral shaft and femoral neck fracture fixation is dictated by the urgency of femoral neck reduction in order to decrease the rates of avascular necrosis of the femoral head. As such, open reduction of the femoral neck should precede fixation of the femoral shaft. Following this, as the implant construct fixing the femoral neck will block antegrade intramedullary nailing and will cause increased stresses across the femoral neck, retrograde intramedullary nailing is the preferred implant choice for femoral shaft fixation.

How much femoral anteversion is acceptable following femoral intramedullary nailing when compared to the uninjured extremity?

  1. 5 degrees

  2. 10 degrees

  3. 15 degrees

  4. 20 degrees

  5. 25 degrees

 

Discussion

The correct answer is (C). Anatomic studies have shown that in normal subjects differences in femoral anteversion are up to 15 degrees. Studies have also shown that increasing femoral malrotation is associated with increasing incidence of functional gait disturbances. There are several techniques that can be used to obtain appropriate femoral rotation in transverse femoral shaft fractures. A basic technique to establish appropriate femoral rotation includes assessing the cortical diameters across the fracture site. More complex techniques involve using the uninjured extremity to establish appropriate rotation. One technique uses the contralateral extremity to estimate femoral anteversion on the injured side. By using fluoroscopy prior to the case, the angular difference between a true lateral of the femoral neck and true lateral of the knee (femoral anteversion) can be obtained. This can then be used to “dial in” the injured extremity anteversion by ensuring the femoral anteversion has been restored. A second technique utilizing lateral-only imaging uses the neck-horizontal angle to determine anteversion. Using this technique, a true lateral of the knee is obtained. Following this, a lateral view of the proximal femur is obtained without changing the intensifier angle. The angle formed between the femoral neck and a horizontal line at the base of the monitor forms the neck horizontal angle. A third technique that can be used to asses rotation relies on the profile of the lesser trochanter on a true AP of the hip. Again, the uninjured

extremity must be imaged prior to initiating the case and the profile of the lesser trochanter obtained using the uninjured extremity is compared to the injured in order to obtain appropriate rotational alignment.

 

Objectives: Did you learn...?

 

Association of femoral shaft and neck fractures?

 

 

Important diagnostic imaging to obtain in femoral shaft fractures? Importance of the order of fixation in femoral neck/shaft fractures?