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Updated: Jun 6, 2026
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Three-Dimensional Preoperative Virtual Planning in Derotational Proximal Femoral Osteotomy
Published on: February 17, 2023
Creating a "Box View" of Periprosthetic Distal Femur Fractures Using Three-Dimensional Image Processing
Andrew Fithian1, L Henry Goodnough1, Malcolm DeBaun1
1Orthopaedic Surgery Stanford University.
Hawai'I Journal of Health & Social Welfare
|June 5, 2026
Summary
A new "Box View" imaging technique accurately identifies open box femoral components for treating periprosthetic distal femur fractures. This method improves surgical planning by offering high sensitivity and specificity compared to standard imaging.
Area of Science:
- Orthopedic Surgery
- Medical Imaging Analysis
- Biomedical Engineering
Background:
- Retrograde intramedullary nailing for periprosthetic distal femur fractures necessitates an open box femoral component.
- Standard imaging modalities often struggle to definitively identify the presence of an open box.
- Accurate pre-operative assessment is crucial for successful surgical planning and implant selection.
Purpose of the Study:
- To introduce and evaluate a novel three-dimensional (3D) image processing technique, the "Box View," for identifying open box femoral components.
- To compare the diagnostic performance of the Box View against conventional radiography and computed tomography (CT).
Main Methods:
- Pre-operative CT scans from 12 revision total knee arthroplasty patients were reformatted to create a 3D Box View movie.
- Four attending surgeons and six residents interpreted radiographs, CT, and Box View images for the presence of an open box.
- Inter-observer reliability was assessed using 2-factor ANOVA; sensitivity and specificity were determined using the Stuart-Maxwell test.
Main Results:
- The Box View demonstrated 81% sensitivity and 97% specificity, with 100% positive predictive value and 85% negative predictive value.
- Box View specificity (97%) was significantly superior to radiographs (53%) and CT (50%).
- Box View sensitivity (81%) was significantly better than CT (34%) and comparable to radiographs (77%).
- Inter-observer agreement was highest for the Box View (0.88) compared to radiographs (0.65) and CT (0.09).
Conclusions:
- The Box View is a novel and effective pre-operative planning tool for managing distal femur fractures requiring open box components.
- This technique offers high diagnostic accuracy, including excellent positive and negative predictive values.
- The Box View exhibits superior inter-observer reliability, enhancing its utility in clinical practice.
