Novel potential marker for native anteversion of the proximal femur

Abstract

Identifying native femoral version from proximal femoral landmarks would be of benefit both for preoperative assessment as well as intraoperatively. To identify potential markers for femoral anteversion, an empirical framework was developed for orientation-independent analysis of the proximal femur from pelvic CT to allow for segmentation of the proximal femur into five constituent regions: Femoral head, femoral neck, greater trochanter, lesser trochanter and femoral shaft. The framework is based on the identification of differences in the radius of curvature at anatomic zones of transition between regions of the proximal femur, followed by non-linear geometric shape fitting. The framework is applied to 86 proximal femurs segmented from pelvic CTs, with at least 2 cm of proximal femur remaining below the lesser trochanter, obtained for non-musculoskeletal pathology to investigate potential proximal femoral markers for native femoral version. The analysis of the proximal femur suggests a fixed relationship between the maximal femoral canal diameter 1 cm proximal to the base of the lesser trochanter from the center of the greater trochanter and the femoral neck axis of 4.13° +/- 4.99°. Further full-length femoral studies are needed to confirm the relationship of the maximal canal diameter as a proxy for native femoral anteversion. Published by Wiley Periodicals, Inc. J Orthop Res 35:1724-1731, 2017.

Automated femoral version estimation without the distal femur

“…We have developed a feature recognition algorithm to automatically identify multiple femoral landmarks from 3D rendered femora. Six potential axes for calculating version, all based on landmarks visible during hip surgery, as previously analyzed, were automatically identified. Further, the algorithm was used to create a statistical shape model of the proximal femur from a series of landmark points.…”

“…The lesser trochanter was identified as the region of greatest curvature in the medial femur above the identified shaft. With the vertices and faces identified as belonging to the head, neck, shaft, and lesser trochanter removed, the greater trochanter was identified as the unassigned region superior and lateral to the lesser trochanter . The posterior condylar line was defined as the line connecting the posterior‐most points of the medial and lateral condyles, from which true version was measured between this line and the neck axis.…”

“…Following the initial goal of a predictor of femoral version using only landmarks visualized intraoperatively, six proximal axes were assessed (Fig. ): lesser trochanter axis (LTA), intertrochanteric axis (ITA), maximum diameter axis (MDA), maximum diameter greater trochanter axis (MDAGT), posterior calcar axis (PCA), greater trochanter calcar axis (GTC). The maximum diameter axis has been defined previously as the axis connecting the two most distant points in a section of the femoral shaft in the transverse plane two centimeters above the lesser trochanter.…”

Capturing the 2019 H. R. Lissner Medal Presentation With Jennifer S. Wayne

“…The last computational work discussed was the development of an automated system to provide 3D analysis of important hip measures for diagnosis and pre-operative planning purposes directly the CT scanned pelvis and hip [19][20][21]. The algorithms developed identify critical bony features-pubic tubercle, ASIS (anterior superior iliac spine), AIIS (anterior inferior iliac spine), and acetabular rim-from the pelvis.…”

Correlation between lag screw route and the ideal insertion point of the intramedullary nail

“…For example, when inserting the short femoral nail to surgically treat intertrochanteric fractures of the femur or determining the entry point and anteversion of the femoral stem in total hip arthroplasty (THA), knowledge of the superior aspect of the proximal femur anatomy is necessary. Previous studies have investigated the morphology of the femur 1 – 6 . A cadaveric study investigated the greater trochanter morphology and assessed the optimal insertion point of the intramedullary nail; however, there was no information on a correlation between the route of the lag screw and the ideal insertion point of the intramedullary nail 5 .…”