Heterotopic Ossification in Cementless Trochanteric Sparing Short Stem Total Hip Arthroplasty
Bibliographic record
Abstract
Background: Heterotopic ossification (HO) is a common complication of total hip arthroplasty (THA), which can adversely affect patient satisfaction. Although the direct anterior approach (DAA) has been associated with lower rates of HO, the exact clinical impact of even low-grade ossification following DAA THA remains underreported. We aimed to assess the clinical impact of HO in DAA THA and identify demographics and implant-related risk factors. Methods: A retrospective single-center cohort study of 348 hips treated via DAA THA with a cementless short stem between January 2011 and December 2021 was performed. HO was graded at ≥12 months using the Brooker classification on standardized anteroposterior radiographs. The Harris Hip Score (HHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Visual Analogue Scale (VAS) were assessed at a mean of 4.3 years of follow-up. Comparative analyses and multivariable logistic regression were performed to identify independent predictors of HO. Results: HO occurred in 18.1% of hips: Brooker grade I in 12.4%, II in 3.0%, and III in 3.0%; no grade IV lesions developed. At final follow-up, patients without HO had significantly better outcomes compared with those with HO (all p < 0.001). When stratified by severity, even low-grade HO (Brooker I-II) was associated with significantly worse WOMAC (p = 0.023) and HHS (p < 0.001) compared with the non-HO group. Although VAS pain was higher in the low-grade group, the difference did not reach statistical significance (p = 0.084). On multivariable analysis, independent implant-related risk factors included use of the Continuum acetabular cup (odds ratio [OR] 2.10; p = 0.014), each additional millimeter of cup diameter (OR 1.16; p = 0.003), and longer femoral neck length (OR 2.06; p = 0.006). Conclusions: HO was observed in nearly one-fifth of hips, and even low-grade ossification was associated with significantly worse mid-term functional outcomes. Cup design, size, and neck length were identified as significant, modifiable predictors of HO risk. Careful implant selection may help reduce the incidence of HO and enhance postoperative function. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
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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 | 0.003 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".