CASE33 femoral neck fractures

 

A 23-year-old male presents to the emergency department following a hard landing while skydiving. He is unable to ambulate secondary to pain in his right hip. He has pain with logroll and while conducting a straight leg raise. His leg is shortened and externally rotated. Pulses and neurologic examination is symmetric to his contralateral side. An AP radiograph of the right hip is shown in Figure 6–35.

 

 

 

Figure 6–35

 

What treatment option is most reasonable for this patient?

1. Closed reduction and protected weight bearing for 3 months

2. Closed reduction and percutaneous screw fixation

3. Total hip arthroplasty

4. Hemiarthroplasty

5. Open reduction and internal fixation

 

Discussion

The correct answer is (E). This is a young patient with a displaced femoral neck fracture. The Garden classification and Pauwels classification are most commonly used to classify these fractures. The Garden classification (Table 6–4) is based on

the degree of displacement and fracture orientation. Garden 1 fractures are incomplete/valgus impacted fractures. Due to the valgus impaction, this is considered a stable fracture. Garden 2 fractures are complete, nondisplaced fractures. This is also considered a stable fracture pattern. Although stable fractures in young patients who comply with weight-bearing restrictions for a minimum of 6 to 8 weeks can be treated nonoperatively; due to potential complications with displacement, the majority are treated surgically with ORIF. Garden 3 and 4 fractures are unstable fractures with incomplete displacement and complete displacement respectively. These require prompt open reduction and internal fixation in the young patient due to concern for AVN, which can be as high as 40% in displaced femoral neck fractures. In high-energy injuries with a vertical fracture line, the Pauwels classification (Table 6–5) can be used to describe the fracture stability based on the amount of vertical shear force across the fracture. Higher Pauwels classification correlates with increased instability and higher rates of nonunion and AVN, as weight transmission across the fracture site creates higher shear forces at a higher Pauwels angle. In young patients with femoral neck fractures, the standard of care is open reduction and internal fixation of displaced femoral neck fractures in order to obtain an anatomic reduction and decrease postoperative complications. Cephalomedullary nailing is not indicated in this fracture pattern. Arthroplasty in a young patient is also not indicated as a primary surgical option.

 

Table 6–4 GARDEN CLASSIFICATION (LOW ENERGY)

 

Type I	Incomplete, valgus impacted fracture
Type II Complete, nondisplaced fracture Type III Complete fracture with <50% displacement
Type IV	Completely displaced fracture

 

Table 6–5 PAUWELS CLASSIFICATION (HIGH ENERGY)

 

Type I	Vertical fracture line <30 degrees from horizontal
Type II Vertical fracture line 30–50 degrees from horizontal
Type III	Vertical fracture line greater than 50 degrees from horizontal

 

The patient returns to clinic 3 months postoperatively following open reduction and internal fixation with a sliding hip screw and antirotation screw. He now

complains of hip pain. He states that his pain originally improved but has now been increasing over the last month. He is otherwise doing well and denies any repeat trauma.

What is the patient’s most likely diagnosis?

1. Avascular necrosis

2. Nonunion

3. Posttraumatic arthritis

4. Symptomatic hardware

5. Malunion

 

Discussion

The correct answer is (A). Urgent anatomic reduction and internal fixation is required in displaced femoral neck fractures in order to preserve the blood supply to the femoral head. The medial femoral circumflex artery supplies the majority of the blood supply to the femoral head with the lateral femoral circumflex, the ascending cervical branches, and the artery of the ligamentum teres providing a lesser degree of blood. Disruption of these vessels with increasing displacement is presumed to increase the risk of avascular necrosis which studies have shown occur in 10% to 40% of displaced fractures. Although increased intracapsular pressure due to hematoma formation has been theorized to increase AVN rates, this has not been proven. Fracture nonunion is a common complication following open reduction and internal fixation of femoral neck fractures occurring 10% to 30% of cases in multiple studies. Nonunion is related to the degree of initial displacement and more commonly associated with a varus malreduction.

Repeat radiographs taken in clinic demonstrate loss of fracture reduction with varus malposition.

What is the next treatment option?

1. Total hip arthroplasty

2. Hemiarthroplasty

3. Revision open reduction and internal fixation with screw fixation

4. Valgus intertrochanteric osteotomy with blade plate fixation

5. Revision open reduction and internal fixation with dynamic hip screw and iliac crest bone graft

Discussion

The correct answer is (D). Treatment of failed open reduction and internal fixation of a femoral neck fracture in a young patient requires a valgus intertrochanteric osteotomy with a blade plate. The valgus intertrochanteric osteotomy converts the shear forces across the nonunion site into a compressive force, which improves the potential for progressing to union. Revision open reduction and internal fixation with screws or blade plate with bone grafting are not preferred revision options. Furthermore, arthroplasty options in young patients are not preferred due to complications and longevity concerns associated with these implants.

 

Objectives: Did you learn...?

 

Classification of femoral neck fractures?

 

 

Treatment options for primary and revision femoral neck fractures? Complications of femoral neck fractures?