Bi-planar calibration method for templating of hip joint arthroplasty: phantom study and proof of concept
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Bi-planar calibration method for templating of hip joint arthroplasty: phantom study and proof of concept. / Boese, Christoph Kolja; Rolvien, Tim; Henes, Frank Oliver; Beil, Frank Timo; Strahl, André; Ries, Christian.
in: INT ORTHOP, Jahrgang 47, Nr. 5, 05.2023, S. 1249-1257.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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T1 - Bi-planar calibration method for templating of hip joint arthroplasty: phantom study and proof of concept
AU - Boese, Christoph Kolja
AU - Rolvien, Tim
AU - Henes, Frank Oliver
AU - Beil, Frank Timo
AU - Strahl, André
AU - Ries, Christian
N1 - © 2023. The Author(s).
PY - 2023/5
Y1 - 2023/5
N2 - PURPOSE: Calibration of radiographs is a critical step in digital templating for hip arthroplasty. Calibration errors of > 1.5% lead to over- or undersizing of the templated implants and may affect logistics and patient safety. Contemporary calibration methods are known to be imprecise with average errors of 6.5% and wide variance. A novel bi-planar radiograph-based calibration method is proposed, and a phantom study was conducted as proof of concept.METHODS: A spherical external calibration marker (ECM) is placed in front of the pubic symphysis of a pelvic bone model at twelve different positions. For each marker position, standard anteroposterior radiographs and four corresponding lateral radiographs with different degrees of rotation (0°-30°) are taken (overall, 60 radiographs). Calibration factors are calculated for an internal calibration marker (ICM) at the centre of the right hip (reference) and the ECM using a novel algorithm. Rotation and marker positions simulate foreseeable use errors and misplacements and aim to test robustness of the method against these errors.RESULTS: ECM calibration factor was 125.9% (range 124.7-127.2), and the mean ICM calibration factor was 126.6% (range 126.2-127.1) ([Formula: see text]). Four images (8.3%) were beyond the 1% error threshold (all with 30° rotation). The mean difference was 0.79% (SD 0.49).CONCLUSION: The bi-planar method precisely predicts the true calibration factor of the hip joint plane under various conditions. In lateral radiographs, rotation of up to 20° did not adversely affect the precision and all images had calibration errors below the threshold for clinical significance.
AB - PURPOSE: Calibration of radiographs is a critical step in digital templating for hip arthroplasty. Calibration errors of > 1.5% lead to over- or undersizing of the templated implants and may affect logistics and patient safety. Contemporary calibration methods are known to be imprecise with average errors of 6.5% and wide variance. A novel bi-planar radiograph-based calibration method is proposed, and a phantom study was conducted as proof of concept.METHODS: A spherical external calibration marker (ECM) is placed in front of the pubic symphysis of a pelvic bone model at twelve different positions. For each marker position, standard anteroposterior radiographs and four corresponding lateral radiographs with different degrees of rotation (0°-30°) are taken (overall, 60 radiographs). Calibration factors are calculated for an internal calibration marker (ICM) at the centre of the right hip (reference) and the ECM using a novel algorithm. Rotation and marker positions simulate foreseeable use errors and misplacements and aim to test robustness of the method against these errors.RESULTS: ECM calibration factor was 125.9% (range 124.7-127.2), and the mean ICM calibration factor was 126.6% (range 126.2-127.1) ([Formula: see text]). Four images (8.3%) were beyond the 1% error threshold (all with 30° rotation). The mean difference was 0.79% (SD 0.49).CONCLUSION: The bi-planar method precisely predicts the true calibration factor of the hip joint plane under various conditions. In lateral radiographs, rotation of up to 20° did not adversely affect the precision and all images had calibration errors below the threshold for clinical significance.
U2 - 10.1007/s00264-023-05747-4
DO - 10.1007/s00264-023-05747-4
M3 - SCORING: Journal article
C2 - 36881153
VL - 47
SP - 1249
EP - 1257
JO - INT ORTHOP
JF - INT ORTHOP
SN - 0341-2695
IS - 5
ER -