The Reliability of Classifications of Proximal Femoral Fractures with 3-Dimensional Computed Tomography: The New Concept of Comprehensive Classification

Abstract

The reliability of proximal femoral fracture classifications using 3DCT was evaluated, and a comprehensive “area classification” was developed. Eleven orthopedists (5–26 years from graduation) classified 27 proximal femoral fractures at one hospital from June 2013 to July 2014 based on preoperative images. Various classifications were compared to “area classification.” In “area classification,” the proximal femur is divided into 4 areas with 3 boundary lines: Line-1 is the center of the neck, Line-2 is the border between the neck and the trochanteric zone, and Line-3 links the inferior borders of the greater and lesser trochanters. A fracture only in the first area was classified as a pure first area fracture; one in the first and second area was classified as a 1-2 type fracture. In the same way, fractures were classified as pure 2, 3-4, 1-2-3, and so on. “Area classification” reliability was highest when orthopedists with varying experience classified proximal femoral fractures using 3DCT. Other classifications cannot classify proximal femoral fractures if they exceed each classification's particular zones. However, fractures that exceed the target zones are “dangerous” fractures. “Area classification” can classify such fractures, and it is therefore useful for selecting osteosynthesis methods.

Incidence and Clinical Outcomes of Hip Fractures Involving Both the Subcapital Area and the Trochanteric or Subtrochanteric Area

“…Their mean age was 82 years (range, 26-108 years). The type of fracture was retrospectively evaluated using the area classification [4, 5] based on X-ray films and 3D-CT images.…”

“…It is also possible to detect fractures involving the subcapital area to the trochanteric or subtrochanteric region by using this classification. In addition, this classification is reliable and useful for selecting therapeutic strategies [4, 5].…”

“…The subcapital area is defined as Area 1, the base of the femoral neck area is defined as Area 2, the trochanteric area is defined as Area 3, and the subtrochanteric area is defined as Area 4. Then, a fracture line that exists only in Area 1 is classified as a Type 1 fracture, and one in Area 1 and Area 2 is classified as a Type 1-2 fracture [5].…”

The choice of internal fixator for fractures around the femoral trochanter depends on area classification

“…Therefore, the choice of internal fixator for such fractures around the femoral trochanter is very difficult. Thus, area classification has been proposed as a comprehensive classification that can identify such fractures (Kijima et al 2014 ).…”

“…In this classification, so-called neck fractures, basicervical fractures, trochanteric fractures, and subtrochanteric fractures are defined by the boundary lines. In addition, area classification can classify the fractures that cross the zones (Kijima et al 2014 ). Fractures within only the trochanteric part are classified as type 3, fractures extending from the trochanteric part to the basal neck are classified as type 2–3, fractures extending from the trochanteric part to the subtrochanteric part are classified as type 3–4, and fractures extending from the basal neck to the subtrochanteric part are classified as type 2–3–4 (Fig.…”