A 3D-CT Analysis of Femoral Symmetry-Surgical Implications.

Joan Ferràs-Tarragó,Cristina Ramírez-Fuentes,Francisco Baixauli-García,Vicente Sanchis-Alfonso,Alejandro Roselló-Añón

doi:10.3390/jcm9113546

Abstract

Background: Mirroring the image of the affected side is a widely used technique for surgical planning in orthopedic surgery, especially for fractures and custom-made prostheses. Our objective is to evaluate the three-dimensional symmetry of the femurs using finite element analysis and manual alignment. Methods: Using the computed tomography of 15 patients without lower limb pathology, 30 3D biomodels of their femurs were obtained. The error obtained through image manipulation was calculated and broken down into a rendering error and a manual overlay error. The Hausdorff–Besicovitch method was applied to obtain the total asymmetry. The manipulation error was theb subtracted from it to obtain the intrapersonal asymmetry. Results: The mean intrapersonal asymmetry was 0.93 mm. It was obtained by subtracting the error derived from rendering and alignment of 0.59 mm (SD 0.17 mm) from the overall mean error of 1.52 mm (SD 1.45). Conclusions: Intrapersonal femoral asymmetry is low enough to use the mirror image of the healthy side as a reference for three-dimensional surgical planning. This type of planning is especially useful in deformity surgery when the objective of the surgery is not to restore only one specific parameter but to obtain a general functional morphology when a healthy contralateral femur is available.

Highlights

IntroductionNew software programs allow for the management of 3D images in an economical and simple way
The mean error due to asymmetry was calculated at 0.93 mm, subtracting the rendering error and alignment error from the total error (Figures 4 and 5)
Translated into angles, we would restore the normal anatomy for that patient with a total mean margin of error of 1◦ of femoral anteversion and an approximate maximum mean error of 5◦ if we were to use the healthy side as a reference for correction in a unilateral derotational femoral osteotomy

Summary

Introduction

New software programs allow for the management of 3D images in an economical and simple way It has made for the routine use of this technology in many orthopedic surgery and trauma departments worldwide. Conclusions: Intrapersonal femoral asymmetry is low enough to use the mirror image of the healthy side as a reference for three-dimensional surgical planning. This type of planning is especially useful in deformity surgery when the objective of the surgery is not to restore only one specific parameter but to obtain a general functional morphology when a healthy contralateral femur is available

Objectives

Results

Discussion

Conclusion