Page 27 - Delaware Medical Journal - September/October 2020

P U
C
C
C
C
CBA
A
ALS
S
S
S
SDIE
E
E
E
E
E
E
E ECI A R R R
R
R
RHGE
E
E
ENP
P
P
P
PAO
O
O
OLSR
R
R
RTIHST
T
T
T
T
T
Figure 1 Femur and tibia osteotomy process showing 40° femoral internal rotation and 35° tibial external rotation (lower extremity malalignment syndrome). A and B - Parallel femoral and tibial pins (0° rotation) C - Femoral and tibial osteotomies (pins shows femur and tibial rotation)
INTRODUCTION
An appropriate analysis of lower limb deformity is required before surgeons consider a treatment or procedure plan.1 Currently, radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) are the
most commonly used methods to
study skeletal alignment concerns.2 However, these tools generally give good measurements in only two dimensions (coronal and sagittal). Transverse
plane alignment is also important
planning. The axial plane, which should be part of the complete analysis, is complex due to the bone morphology;
routine radiographs, and change in different segments of the bone. Often, measurements require holding still for an MRI, or there may be a concern
about the high radiation exposure
required to evaluate the whole lower extremity by CT scan; for these reasons, axial measurements are sometimes overlooked.3
EOS (ArtVentive Medical Group, Inc., San Marcos, CA) is a newly-emerged imaging method that may provide an accurate solution for these triplane measurements. This is a low-dose radiation method that is capable of producing full-length imaging while the patient is in a weight-bearing position.4 This special software can create a three- dimensional model and calculate many alignment measurements, including axial alignment. Similar features have been developed with the CT scan; however, high radiation and non-weight-bearing position with a longer time for imaging make CT scan less attractive to surgeons. Three-dimensional gait analysis through the use of multiple video cameras
allows for the assessment of functional
kinematics and kinetics. This option uses no radiation and the assessment
is performed during weight bearing in stance phase or swing phase of gait. However, gait labs involve sophisticated equipment, trained people, and a longer assessment for each evaluation.
The combination of severe deformities, especially rotational deformity, the impact of positioning during the imaging test, and the technician’s experience could all affect the measurements, resulting in inappropriate treatment.4
To choose the appropriate technique
to evaluate a patient, it is important to understand variables such as accuracy, reliability, exposure to radiation,
special equipment, time, cost, etc.5 The purpose of this study was to compare the accuracy and reliability of CT scans, EOS, and gait laboratory analysis for measurement of femoral and tibial torsion in the axial plane.
Del Med J | September/October 2020 | Vol. 92 | No. 5
219