Compaction Effect on Different Densities of Cancellous Bone and Immediate Stability of an Angle Stable Interlocking Nail in a Distal Femoral Osteotomy Model
Bibliographic record
Abstract
Introduction: Interlocking nails are commonly used in distal femoral varus correction associated with medial patellar luxation. Intraoperative femoral condyle manipulation may weaken the nail/bone interface, jeopardize initial nail stability prior to locking and increase the risk of malalignment. Bone compaction, as opposed to traditional reaming, potentially improves the nail/bone interface mechanical properties. Our aim was to evaluate the effect of compaction on the mechanical properties of the bone/nail interface in a femoral condylar bone model. Materials and Methods: Foam models of different densities (7.5, 10, 15, and 20 PCF, n = 5/group) were prepared using either standard line-to-line reaming (7 mm) or sequential compaction with custom 4 to 7-diameter mandrels. Five samples per group were tested in mediolateral bending. Impaction stiffness was assessed for each mandrel size and a 7 mm I-Loc nail in compacted foams. Three specimens were evaluated by micro-CT to define the effects of compaction on foam microstructure. Results: Compaction increased initial construct stiffness and load across all tested foam densities ( p < 0.0001). Impaction showed increasing nail/foam interface bending stiffness from 4 to 7 mm mandrel with the 7 mm I-Loc nail performing similarly to the 6 mm mandrel. Micro-CT scans demonstrated that higher-density foams (15 and 20 PCF) exhibited more pronounced differences between drilled and compacted samples. Compaction effects on microstructure showed increased local density and altered pore morphology in compacted regions. Discussion/Conclusion: In a distal femoral osteotomy model, cancellous bone compaction significantly increases the immediate stability of the bone/nail interface regardless of bone density, which may prove beneficial in juvenile bone. Acknowledgment L.M.D. is an inventor of an I-Loc Angle Stable Interlocking Nail, US Patent #8,435,238 B2, he receives royalties from Michigan State University and teaching honorarium: BioMedtrix/Movora I-Loc program. This study was funded by the Michigan State University Endowed Research Fund. Publication History Article published online: 15 July 2025 © 2025. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| 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".