Page 30 - Delaware Medical Journal - September/October 2020

TABLE 1. COMPARATIVE FINDINGS: CT, EOS, AND GAIT LAB PRE- AND POST-FEMORAL OSTEOTOMY
FEMUR
Pre-osteotomy Average Degrees (Each Test)
Post-osteotomy Average Degrees (Each Test)
Degree Correction (Each Test)
Expected Degree Correction
CT
-16.3 (-17, -16, -16)
23.3 (23, 24, 23)
39.7 (40, 40, 39)
40
EOS
-8.0 (-10, -6, -8)
24.0 (24, 25, 23)
32.0 (34, 31, 31)
40
Gait lab
-15.1 (-14, -18, -14)
42.3 (40, 43, 44)
57.4 (54, 61, 58)
40
CT, computed tomography
TABLE 2. COMPARATIVE FINDINGS: CT, EOS, AND GAIT LAB PRE- AND POST-TIBIAL OSTEOTOMY
TIBIA
Pre-osteotomy Average Degrees (Each Test)
Post-osteotomy Average Degrees (Each Test)
Degree Correction (Each Test)
Expected Degree Correction
CT
-26.0 (-26, -26, -26)
-60.0 (-60, -60, -60)
34.0 (34, 34, 34)
35
EOS
4.6 (2, 4, 8)
-21.0 (-22, -21 -20)
25.6 (24, 25, 28)
35
Gait lab
3.1 (2, 4, 4)
-31.9 (-30, -33, -33)
35.0 (32, 37, 37)
35
CT, computed tomography
in the full upright and weight-bearing position.5,12 However, most of these studies have been reported in patients without severe torsional problems or without comparative analysis between baseline torsion and postoperative torsion correction.4 Our study reported reduced accuracy in analyzing severe rotational problems because of the difficulty in identifying landmarks (superposition of landmarks). Similar limitations were reported by other authors.4
Based on our study using this model, we conclude that CT is the most precise method to analyze the axial plane in the femur and is a very good option for the tibia. The gait laboratory was imprecise in analyzing the rotational deformity
in the femur due to the inability to separate multiple movements of the
hip joint from changes in femoral torsion. However, we obtained the
most accurate measurement for tibial torsion in this model with a fixed- hinge knee axis and no soft tissue. In
a patient environment, the difficulty of identifying the knee axis and the movement of soft tissue would likely reduce this accuracy. EOS was less accurate but likely had clinically acceptable results in analyzing rotational problems. However, severe rotational deformities may make EOS less reliable due to the difficulty of identifying bony landmarks.
COMPLIANCE WITH ETHICAL STANDARDS
Funding:
Conflict of Interest: The authors declare that they have no conflict of interest.
Ethical Approval: This study did not need approval from our Institutional Review Board or Animal Ethics Committee as no studies were performed on humans or animals.
CONTRIBUTORS
■ CARLOS PARGAS, MD is a researcher
at Nemours/Alfred I. duPont Hospital
for Children in Wilmington. He currently participates in multiple clinical research projects and contributes to the development of chapters for pediatric orthopedics books.
■ ADOLFREDO SANTANA, MD is a former research fellow at Nemours/Alfred I. duPont Hospital for Children. He is currently a pediatric orthopedic surgeon in the Department of Orthopedics and Traumatology, Clinic Center “Leopoldo Aguerrevere,” Caracas, Venezuela. His sub-specialty is limb lengthening and reconstruction.
■ AHMET IMERCI, MD is a former research fellow at Nemours/Alfred I. duPont Hospital for Children. He is currently an Associate Professor in the Department of Orthopaedic and Traumatology, Faculty of Medicine – Mugla Sitki Kocman University, Turkey.
■ FREEMAN MILLER, MD is an emeritus pediatric orthopedic surgeon at Nemours/ Alfred I. duPont Hospital for Children. His sub-specialty is cerebral palsy.
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Del Med J | September/October 2020 | Vol. 92 | No. 5