Comparison of periprosthetic bone remodeling after implantation of anatomic and tapered cementless femoral stems in total hip arthroplasty
Bibliographic record
Abstract
INTRODUCTION: Current total hip arthroplasty (THA) implant usage trends favor cementless fixation, and plenty studies have demonstrated that numbers of cementless femoral stems are associated with excellent long-term survivorship and functional outcomes. Various types of cementless femoral stems have been developed and utilized in multiple applications, including straight, tapered, anatomic, customized, short, and even neck stems. All of these designs aimed to achieve maximal primary stability and promote osseointegration. Nevertheless, stress-shielding and periprosthetic bone loss continue to occur and remain critical issues in promoting long-term survivorship of THA. Considering anatomic and tapered stems are the most popular cementless designs today, this prospective cohort study aimed to investigate the effect of stem design on stress-shielding and periprosthetic bone remodeling after implantation of an anatomic stem with proximal fixation (Ribbed Hip system; Waldemar Link, Hamburg, Germany) and the direct comparison to a fully coated tapered stem (LCU Hip system; Waldemar Link). MATERIALS AND METHODS: This prospective cohort study will comprise patients who receive primary unilateral THA with the Ribbed anatomic hydroxyapatite (HA)-coated stem or LCU tapered fully HA-coated stem. The changes in periprosthetic bone mineral density after insertion of Ribbed and LCU stem prostheses will be assessed by means of dual-energy X-ray absorptiometry in the periprosthetic region of interest according to Gruen and colleagues. Standard anteroposterior and lateral plain radiography will be performed for qualitative assessment of the periprosthetic bone remodeling. The following items will be analyzed or measured on follow-up radiographs to compare with the initial appearance on the radiographs taken immediately postoperatively: cortical thickness in each Gruen zone, fitness of the distal stem within the isthmus, femoral stem alignment, radiolucent line, reactive line, periosteal bone reactions, and subsidence. Biologic fixation and stability of the cementless implant will be evaluated using Engh grading scale, and heterotopic ossification will be graded according to Brooker classification. Furthermore, Harris hip score and Western Ontario and McMaster Universities Osteoarthritis Index Score will also be assessed for postoperative functional evaluation. These radiologic and clinical assessments will be taken postoperatively, at 6 months, 1, 2, 3, 4, and 5 years after surgery. ETHICS AND DISSEMINATION: This study was approved by The First Affiliated Hospital of Chongqing Medical University Ethics Committee. The study results will be disseminated at national and international conferences and published in peer-reviewed journals. STUDY REGISTRATION: Chinese Clinical Trial Registry (http://www.chictr.org.cn): ChiCTR1800017841.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".