Clin Orthop Surg.  2012 Mar;4(1):66-71. 10.4055/cios.2012.4.1.66.

Progression of a Fracture Site Impaction as a Prognostic Indicator of Impacted Femoral Neck Fracture Treated with Multiple Pinning

• Yoon PW
• Shin YH
• Yoo JJ
• Yoon KS
• Kim HJ

• KMID: 1245400
• DOI: http://doi.org/10.4055/cios.2012.4.1.66

Abstract

BACKGROUND
We evaluated the clinical and radiologic results of impacted femoral neck fractures treated with multiple pinning and determined the influence of the progression of impaction at the fracture site on clinical outcome.
METHODS
There were 34 patients with a mean age of 65.5 years. The mean follow-up period was 3.4 years. Progression of fracture site impaction was measured using an articulo-trochanteric distance index and the percentage decrease in the articulo-trochanteric distance index between follow-up intervals. The failure of treatment was clarified as non-union and avascular necrosis. Other characteristics of the patients, including mean waiting time for surgery, preoperative Singh index score, and body mass index, were also measured to evaluate the influence on the clinical outcome of surgery.
RESULTS
There were 6 fractures which were not treated successfully (3 non-union, 8.8% and 3 avascular necrosis, 8.8%). The mean percentage decrease of the articulo-trochanteric distance index within the first 6 weeks after surgery was 4.5% in the successful group and 25.1% in the failure group (p < 0.001). There was also a significant mean percentage decrease in the articulo-trochanteric distance index between 6 weeks and 3 months (p < 0.001).
CONCLUSIONS
Primary stabilization with Knowles pins for impacted femoral neck fractures had a reasonable clinical outcome with low morbidity. Despite a significant difference of a mean percentage decrease in the articulo-trochanteric distance index between the successful group and the failure group, we could not verify it as a risk factor for failure of treatment because the odds ratio was not statistically significant.

Keyword

Impacted femoral neck fractures; Fracture fixation; Treatment outcome

MeSH Terms

Adult
Aged
Aged, 80 and over
Bone Nails
Female
Femoral Neck Fractures/complications/radiography/*surgery
Femur Head Necrosis/etiology/radiography
Follow-Up Studies
*Fracture Fixation, Internal
Fractures, Ununited/radiography
Hip Joint/*pathology/radiography
Humans
Male
Middle Aged
Odds Ratio
Treatment Outcome

Figure

• 

  Fig. 1 The fractures were classified as valgus (A) or varus (B) based on the location of the impaction and the alignment of femoral head trabeculae on plain anteroposterior radiographs.

• 

  Fig. 2 Articulo-trochanteric distance (a) is determined by two lines, a line perpendicular to the anatomic axis of the femur through the superiormost aspect of the femoral head and a line parallel to line 1 through the superiormost aspect of the greater trochanter.

• 

  Fig. 3 Plain radiographs show preoperative valgus-impacted fracture (A) and progressive fracture site impaction 6 weeks postoperative (B). The articulo-trochanteric (ATD) index is determined by the ATD of the affected side (b, d) divided by the ATD of the unaffected side (a, c). The percentage decrease in the ATD index between the follow-up intervals is calculated using the following formula: Percentage decrease of ATD index (%) = [(b/a - d/c)/b/a] × 100.

• 

  Fig. 4 (A) Preoperative radiograph showed a valgus-type impacted femoral neck fractures. (B) Union of the fracture site was confirmed on a radiograph 6 months postoperatively. (C) Twelve months post-operatively there was femoral head collapse and screw cut-out, indicating avascular necrosis.

• 

  Fig. 5 A plain radiograph shows a paradoxical increase of the articulo-trochanteric (ATD) in valgus-type impacted femoral neck fractures of the left hip. In this case, the ATD of the affected side (a) is 25 mm, and the unaffected side (b) is 29 mm.

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