2D measurements of cup orientation are less reliable than 3D measurements
- Resource Type
- Authors
- Kinner Davda; Niall Smyth; Alister Hart; Justin Cobb
- Source
- Acta Orthopaedica. 86:485-490
- Subject
- Cup orientation
Orthodontics
medicine.medical_specialty
business.industry
3d analysis
medicine.medical_treatment
General Medicine
Anterior pelvic plane
Acetabulum
Arthroplasty
2d analysis
medicine.anatomical_structure
medicine
Orthopedics and Sports Medicine
Surgery
Radiology
Tomography
business
Pelvis
- Language
- ISSN
- 1745-3682
1745-3674
Background and purpose — 2D analysis of metal-on-metal (MoM) hip arthroplasty (HA) has been conducted in several large series on conventional radiographs with the use of Ein Bild Roentegen Analyse (EBRA) software, but there have been no comparisons with 3D analysis in the literature. The main aim of this study was to quantify the agreement in measurements of cup version of large-diameter MoM hips obtained by EBRA and by 3D computed tomography (3D-CT). The secondary aim was to quantify the agreement for cup inclination. Lastly, we wanted to determine the inter- and intra-observer reliability of both methods.Patients and methods — 87 MoM hips in 81 patients were analyzed for cup inclination and version in 2D on conventional radiographs using EBRA software. The results were compared with 3D measurements using CT.Results — Cup version was underestimated by EBRA when compared to 3D-CT, by 6° on average with the pelvis supine and by 8° on average with the pelvis orientated to the anterior pelvic plane (APP). Fo...