TY  - JOUR
A1  - Braun, Sebastian Benedict
A1  - Brenneis, Marco Uwe
A1  - Holder, Jana
A1  - Meurer, Andrea
A1  - Stief, Felix
T1  - Intra- and interobserver reliability analysis of pediatric lower limb parameters on digital long leg radiographs
T2  - Journal of orthopaedic surgery and research
N2  - Background: Malalignments of the lower extremity are common reasons for orthopedic consultation because it may lead to osteoarthritis in adulthood. An accurate and reliable radiological assessment of lower limb alignment in children and adolescents is essential for clinical decision-making on treatment of limb deformities and for regular control after a surgical intervention.
Objective: First, does the analysis of full-length standing anteroposterior radiographs show a good intra- and interobserver reliability? Second, which parameter is most susceptible to observer-dependent errors? Third, what is the Standard Error of Measurement (SEM95%) of the absolute femoral and tibial length?
Methods: Two observers evaluated digital radiographs of 144 legs from 36 children and adolescents with pathological valgus alignment before a temporary hemiepiphysiodesis and before implant removal. Parameters included Mechanical Femorotibial Angle (MFA), Mechanical Axis Deviation (MAD), mechanical Lateral Distal Femoral Angle (mLDFA), mechanical Medial Proximal Tibial Angle (mMPTA), mechanical Lateral Proximal Femoral Angle (mLPFA), mechanical Lateral Distal Tibial Angle (mLDTA), Joint Line Convergence Angle (JLCA), femur length, tibial length. Intra- and interobserver reliability (ICC2,1), SEM95% and proportional errors were calculated.
Results: The intra- and interobserver reliability for almost all measurements was found to be good to excellent (Intra-ICC2,1: 0.849–0.999; Inter-ICC2,1: 0.864–0.996). The SEM95% of both observers was found to be ± 1.39° (MFA), ± 3.31 mm (MAD), ± 1.06° (mLDFA) and ± 1.29° (mMPTA). The proportional error of MAD and MFA is comparable (47.29% vs. 46.33%). The relevant knee joint surface angles show a lower proportional error for mLDFA (42.40%) than for mMPTA (51.60%). JLCA has a proportional error of 138%. Furthermore, the SEM95% for the absolute values of the femoral and tibial length was 4.53 mm for the femur and 3.12 mm for the tibia.
Conclusions: In conclusion, a precise malalignment measurement and the knowledge about SEM95% of the respective parameters are crucial for correct surgical or nonsurgical treatment. The susceptibility to error must be considered when interpreting malalignment analysis and must be considered when planning a surgical intervention. The results of the present study elucidate that MAD and MFA are equally susceptible to observer-dependent errors. This study shows good to excellent intra- and interobserver ICCs for all leg alignment parameters and joint surface angles, except for JLCA.
Trial registration: This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053.
Level of evidence
I, Diagnostic Study.
KW  - Genu valgum
KW  - Guiding growth
KW  - Leg axis
KW  - Lower limb deformities
KW  - Pediatric orthopedic
KW  - Radiological assessment
KW  - Reliability
Y1  - 2023
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/86573
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-865734
SN  - 1749-799X
N1  - Open Access funding enabled and organized by Projekt DEAL.
N1  - Funding: DFG ; 403837822
N1  - This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053.
N1  - Gefördert durch den Open-Access-Publikationsfonds der Goethe-Universität.
N1  - The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
VL  - 18
IS  - art. 69
SP  - 1
EP  - 12
PB  - Biomed Central
CY  - London
ER  -