Change in cup orientation from supine to standing posture: a prospective cohort study of 419 total hip arthroplasties
Background and purpose: Arthroplasty surgeons traditionally assess cup orientation after total hip arthroplasty (THA) on supine radiographs. Contemporary hip-spine analyses provide information on standing, functional cup orientation. This study aims to (i) characterize cup orientations when supine a...
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| Main Authors: | , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2024-07-22
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| In: |
Acta orthopaedica
Year: 2024, Volume: 95, Pages: 425-432 |
| ISSN: | 1745-3682 |
| DOI: | 10.2340/17453674.2024.41091 |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.2340/17453674.2024.41091 Verlag, kostenfrei, Volltext: https://actaorthop.org/actao/article/view/41091 
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| Author Notes: | Camille Vorimore, Jeroen C. F. Verhaegen, Moritz Innmann, A. Paul Monk, Christopher Ling, and George Grammatopoulos |
| Summary: | Background and purpose: Arthroplasty surgeons traditionally assess cup orientation after total hip arthroplasty (THA) on supine radiographs. Contemporary hip-spine analyses provide information on standing, functional cup orientation. This study aims to (i) characterize cup orientations when supine and standing; (ii) determine orientation differences between postures; and (iii) identify factors associated with magnitude of orientation differences.Methods: This is a 2-center, multi-surgeon, prospective, consecutive cohort study. 419 primary THAs were included (57% women; mean age: 64 years, standard deviation [SD] 11). All patients underwent supine and standing antero-posterior pelvic and lateral spinopelvic radiographs. Cup orientation and spinopelvic parameters were measured. Target cup orientation was defined as inclination/anteversion of 40°/20° ± 10°. A change in orientation (Δinclination/Δanteversion) between postures > 5° was defined as clinically significant. Variability was defined as 2 x SD.Results: Inclination increased from 40° (supine) to 42° (standing) corresponding to a Δinclination of 2° (95% confidence interval [CI] 2-3). Anteversion increased from 25° (supine) to 30° (standing) corresponding to a Δanteversion of 5° (CI 5-6). When supine, 69% (CI 65-74) of THAs were within target, but only 44% (CI 39-49) were within target when standing, resulting in a further 26% (CI 21-30) being out of target when standing. From supine to standing, a clinically significant change in anteversion (> 5°) was seen in 47% (CI 42-52) of cases. Δanteversion was higher in women than in men (6°, CI 5-7 vs 5°, CI 4-5) corresponding to a difference of 1° (CI 1-2), which was dependent on tilt change, standing cup anteversion, age, and standing pelvic tilt.Conclusion: Cup inclination and version increase upon standing but significant variability exists due to patient factors. |
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| Item Description: | Gesehen am 16.12.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1745-3682 |
| DOI: | 10.2340/17453674.2024.41091 |