Management of pediatric femoral neck fractures from classification to surgery: a review of indications based on anatomic and radiographic features of the proximal femur

Figures

• 

  Figure 1. The femoral neck-shaft angle (A) and anteversion angle (B) show that the medial-posterior column (C) of the femoral neck is an important anatomical structure that carries loads during weight-bearing (red arrow), and thus that there is more biomechanical stability in PFNFs (D) without comminuted medial-posterior columns than in those with comminutions (E).

• 

  Figure 2. The nutrient vessels (A) running along the posterior part of the proximal femur, which are susceptible to injury in PFNFs with posterior (POST) translation (B). ANT: anterior.

• 

  Figure 3. PFNF types according to the new classification system of Wang et al. (45), including type I (A) fractures without anterior (ANT) or posterior (POST) translation (not displaced), type II (B) fractures with anterior translation, type III (C) fractures with posterior translation, type IV (D) fractures with comminuted medial-posterior columns and type V (E) subtrochanteric fractures with any direction of displacement.

• 

  Figure 4. Radiographs of different types of PFNFs according to the new classification system reported by Wang et al. (45), including type I without translation, type II with anterior translation, type III with posterior translation, type IV with a medial-posterior comminution (white arrow) and type V with the subtrochanteric femoral fracture.

• 

  Figure 5. Preoperative (A) and postoperative (B, C and D) radiographs of a 6-year-old girl with a unilateral displaced femoral neck fracture. Radiograph (B) taken on the second day after surgery shows that a ‘positive support reduction’ (white arrow) with the medial cortex of the proximal fracture fragment outside that of the distal fracture fragment was achieved after closed reduction and fixation with two large cannulated screws; radiographs (C and D) taken at the 16-month follow-up show the avascular necrosis of the femoral head and the premature closure of the proximal femoral physis of the injured side (C) in relation to those of the uninjured side (D).

• 

  Figure 6. Preoperative (A) and postoperative (B, C and D) radiographs of a 14-year-old boy with a unilateral displaced femoral neck fracture. Radiograph (B) taken on the second day after surgery shows that a ‘positive support reduction’ (white arrow) with the medial cortex of the proximal fracture fragment outside that of the distal fracture fragment has been achieved after closed reduction and three cannulated screws fixation; radiograph (C) taken at the 6-month follow-up shows delayed fracture union; radiograph (D) taken at the 7-month follow-up shows fracture union.

• 

  Figure 7. Preoperative (A) and postoperative (B, C and D) radiographs of a 4-year-old boy with a unilateral displaced femoral neck fracture. Radiograph (B) taken on the second day after surgery shows that ‘negative support reduction’ (white arrow) with the medial cortex of the proximal fracture fragment medial to that of the distal fracture fragment was achieved after open reduction and fixation with two cannulated screws; radiographs taken at the 13-month follow-up show avascular necrosis of the femoral head and premature closure of the proximal femoral physis of the injured side (C) in relation to those of the uninjured side (D).

• 

  Figure 8. Preoperative (A) and postoperative (B, C and D) radiographs of a 11-year-old boy with a unilateral displaced femoral neck fracture. Radiograph (B) taken on the second day after surgery shows that a nonanatomical reduction quality with residual displacement and angular deformity was achieved after open reduction with cannulated screws and plate and Kirschner fixation; radiographs taken at the 38-month follow-up show the avascular necrosis of the femoral head and neck and the narrow and short femoral neck deformity (C) when compared with those of the uninjured side (D).

• 

  Figure 9. The vascular network (A) formed by the intersection of the nutrient vessels (black and white boxes in (A)) within the femoral neck, including the superior retinacular artery (SRA) with small caliber and fewer anastomoses to the nutrient vessels within the medullary cavity in the superior region (black box) and the inferior retinacular artery (IRA) with larger diameter and more anastomoses to the nutrient vessels within the medullary cavity in the inferior region (white box), which would be destroyed after bone fracture (B) and implant insertion (C).

• 

  Figure 10. Three types of reduction quality of surgically treated PFNFs on anteroposterior (AP) radiographs, including anatomic reduction quality (A) with no residual displacement or angular deformity, ‘positive support reduction’ (B) with the medial cortex of the proximal fracture fragment outside that of the distal fracture fragment and ‘negative support reduction’ (C) with the medial cortex of the proximal fracture fragment medial to that of the distal fracture fragment.

• 

  Figure 11. Different types of reduction quality of surgically treated PFNFs on anteroposterior radiographs, including anatomic reduction quality (A) with no residual displacement or angular deformity (red arrow), ‘positive support reduction’ (B) with the medial cortex of the proximal fracture fragment outside that of the distal fracture fragment (white arrow) and ‘negative support reduction’ (C) with the medial cortex of the proximal fracture fragment medial to that of the distal fracture fragment (yellow arrow).

• 

  Figure 12. The optimal treatment protocol for PFNFs, including anatomic reduction (A), placement of a small number of smaller implants in the mid-inferior part of the femoral neck without the need for parallel insertion (A and B) and additional external support (C).