What patient parameters influence lumbar stiffness in patients with hip pathology?
Bibliographic record
Abstract
Lumbar stiffness leads to greater hip dependence to achieve sagittal motion and increases instability after total hip arthroplasty (THA). We aimed to determine parameters that influence lumbar stiffness among patients with hip pathology. We hypothesized that modifiable (degenerative changes, spinal canal stenosis, facet orientation) and nonmodifiable factors (muscle condition) would be associated with lumbar spine stiffness. In this retrospective case-cohort study from a tertiary referral center, consecutive patients presenting at a hip specialist clinic underwent standing and deep-seated radiographic assessment to measure lumbar lordosis (∆LL) (stiffness: ∆LL < 20°), hip flexion (∆PFA: pelvic femoral angle), and degree of degenerative-disc-disease (DDD) (facet osteoarthritis, disc height, endplate proliferative changes). Of these, 65 patients were selected with previous lumbar spine magnetic resonance imaging, allowing to determine lumbar facet orientation, spinal canal stenosis (Schizas classification), and flexor- and extensor-muscle atrophy (Goutallier classification). Mean ∆LL was 45° (range: 11°-72°) and four patients (6%) exhibited spine stiffness. Patients with multilevel DDD (n = 22) had less ∆LL than those with no/single level (n = 43) DDD (34° [range: 11°-53°] vs. 51° [21°-72°]; p < 0.001). Number of DDD levels correlated strongly with ∆LL (ρ = -0.642; p < 0.001). Spinal stiffness was only seen in patients with ≥4 DDD levels. There was no correlation between ∆LL and facet orientation (p > 0.05). ∆LL correlated strongly with extensor atrophy at L3-L4 (ρ = -0.473), L4-L5 (ρ = -0.520), and L5-S1 (ρ = -0.473) and poorly with flexors at L4-L5 (ρ = -0.134) and L5-S1 (ρ = -0.227). Lumbar stiffness is dependent on modifiable (muscle atrophy) and nonmodifiable (extend of DDD) factors. This can guide nonoperative management of hip pathology, emphasizing the relevance of core muscle rehabilitation to improve posture and stiffness. Identification ≥4 DDD levels should alert surgeons of increased THA instability risk. Level of evidence: level IV, cohort series.
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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 | 0.001 | 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".