Effects of Transfixation Pin Positioning on the Biomechanical Properties of Acrylic External Skeletal Fixators in a Fracture Gap Model
Bibliographic record
Abstract
Abstract Objective The aim of this study was to evaluate the biomechanical effects of transfixation pin positioning in acrylic columns of external skeletal fixators (ESF). Study Design Twenty-four type I acrylic ESF were built simulating a fracture gap-model. Transfixation pins were placed centric (n = 12) or eccentric at ¼ of the column diameter (n = 12) in the acrylic columns. Six constructs from each group were subjected to axial compression and four-point bending tests. Stiffness, yield load and mode of failure were recorded. Results Stiffness was not influenced by centring (p = 0.373), but it was higher in four-point bending than in axial compression (p < 0.001). Pin positioning had no influence on the yield (p = 0.535) and failure loads (p = 0.715) in axial compression, nor on the yield load in bending (p = 0.135). Eccentric pin positioning decreased failure loads by 28% in bending (p < 0.001). Conclusion Eccentric position of transfixation pins within the acrylic columns alters the biomechanical properties of type I ESF constructs. While acrylic offers several advantages, when forming the columns, frame strength will be optimized if pins are centrally located.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".