CUP ORIENTATION WHEN STANDING IS SIGNIFICANTLY DIFFERENT TO WHEN SUPINE: IMPLICATIONS FOR PRE-OPERATIVE PLANNING
Bibliographic record
Abstract
Arthroplasty surgeons traditionally assess cup orientation on supine radiographs, which fail to account for individual postural changes when standing. Standing assessments have been proposed for pre-operative THA planning to account spinopelvic characteristics. To-date no large cohort data exists on standing cup orientation post-THA and how this differs to supine assessment. This study aims to 1. Characterize cup orientation supine and standing; 2. Determine cup orientation differences between postures; 3. Identify factors associated with magnitude of orientation difference. This is a two-center, multi-surgeon, prospective, consecutive cohort study. 462 patients (500 hips) that underwent primary THA for hip arthritis were included (58% females; age: 65±11; BMI: 29±5). Most patients underwent anterior approach (65%), followed by posterior (29%) and lateral (6%). All had an uncemented cup. All patients underwent supine and standing AP pelvic and lateral spinopelvic radiographs at 1-year post-THA. Cup orientation was measured using validated software. Target cup orientation was defined as inclination/anteversion of 40/20°±10°. A significant change in orientation (ΔInclination/ΔAnteversion) between postures was defined as >5° Two of the 500 THAs sustained a dislocation. Inclination increased from 41°±7 supine, to 43°±7 standing (p 5°) was seen in 48% of cases. ΔAnteversion was dependent on cup anteversion (ρ=0.5) and standing pelvic tilt (ρ=0.2). Standing cup orientation is associated with significant increase in inclination/anteversion, and many cups might be erroneously considered sub-optimally orientated from standing assessments. If cup orientation targets are defined from standing spinopelvic characteristics the resultant cup inclination/anteversion when supine (in post-op X-Rays) should be lower than the defined standing target. Individual assessment of pelvic tilt can help predict change in cup orientation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".