Bi-planar calibration method for templating of hip joint arthroplasty : phantom study and proof of concept

© 2023. The Author(s)..

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.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:47

Enthalten in:

International orthopaedics - 47(2023), 5 vom: 07. Mai, Seite 1249-1257

Sprache:

Englisch

Beteiligte Personen:

Boese, Christoph Kolja [VerfasserIn]
Rolvien, Tim [VerfasserIn]
Henes, Frank Oliver [VerfasserIn]
Beil, Frank Timo [VerfasserIn]
Strahl, André [VerfasserIn]
Ries, Christian [VerfasserIn]

Links:

Volltext

Themen:

Arthroplasty
Digital radiography
Digital templating
Joint arthroplasty
Journal Article
Total hip arthroplasty

Anmerkungen:

Date Completed 10.04.2023

Date Revised 24.05.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1007/s00264-023-05747-4

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM353869449