3D computer tomography for measurement of femoral position in acl reconstruction.

Tiago Lazzaretti Fernandes,Felipe De Andrade Watai,Nuno Miguel Morais Fonseca Martins,Cyro Albuquerque Neto,Arnaldo José Hernandez,André Pedrinelli

doi:10.1590/1413-78522015230100993

Abstract

Objective: To validate intra- and inter-class correlation coefficients of a transparent 3D-TC protocol and investigate relationships between different axial rotations. Methods: Twenty unilateral knee TCs (iSite - Philips) were evaluated by means of a transparent 3D-TC OsiriX Imaging Software (v.3.9.4), 3D MPR protocol. Mathematical model of femoral tunnel projections acquired on vertical and horizontal rotations from -20 to +20 degrees. Height (h'/H) and length (t'/T) of tunnel projections have been analyzed by the Bernard and Hertel's method. Statistics: power of study=80%, ICC, ANOVA, p<0.05 (SPSS-19). Results: Transparent 3D-TC showed high reliability of both intra-observer (h'/H=0.941; t'/T=0.928, p<0.001) and inter-observer (h'/H=0.921; t'/T=0.890, p<0.001) ICC. ACL Length (t'/T) and Height (h'/H) projections were statistically different on vertical and horizontal rotations: p=0.01 and p<0.001, respectively. Conclusion: This new transparent 3D-TC protocol is an accurate and reproducible method that can be applied for ACL femoral tunnel or footprint measurement with high ICC reliability. Level of Evidence II, Descriptive Laboratory Study.

Highlights

Volume-rendering 3D computed tomography (CT) scan is the preferred imaging technique to evaluate osseous anatomy of the knee and anatomic femoral tunnel position after anterior cruciate ligament (ACL) reconstruction.[1,2,3,4,5,6,7,8] Clinical or biomechanical studies may show an inaccurate relationship between functional outcomes and ACL tunnel positioning if standardized and validated 3D CT scan protocols are not employed.[9]
There was a high reliability of Intraclass Correlation Coefficient (ICC) for both intra and inter-observer measurements related to this transparent image technique method
The most important finding was that this standardized transparent 3D CT scan protocol has high ICC reliability and that small rotation degrees (5o) close to sagittal view[9,13] do not alter ACL measurement values

Summary

Introduction

Volume-rendering 3D computed tomography (CT) scan is the preferred imaging technique to evaluate osseous anatomy of the knee and anatomic femoral tunnel position after anterior cruciate ligament (ACL) reconstruction.[1,2,3,4,5,6,7,8] Clinical or biomechanical studies may show an inaccurate relationship between functional outcomes and ACL tunnel positioning if standardized and validated 3D CT scan protocols are not employed.[9]. 9–11 (Figure 1) Here, we propose an accessible transparent 3D CT measurement protocol for central femoral footprint or ACL tunnel positioning assessment, taking account condyle femoral alignment and a standardized projection of Blumensaat line, as from a mathematical model. -class correlation coefficients of a standardized new transparent 3D CT scan for femoral footprint ACL measurement with a simulation of central ACL tunnel position in different axial rotations in both vertical and horizontal axes, as it was an imaging laboratory study. It was hypothesized that horizontal and vertical rotations could alter the relationship between radiological landmarks (Blumensaat line and lateral condyle wall) and simulated central ACL position in Bernard et al.[12] method in this transparent 3D CT protocol

Methods

Results

Conclusion