Bone Compaction Improves Immediate Mechanical Stability of the Nail-Bone Interface
Bibliographic record
Abstract
Introduction: Medial patellar luxation and distal femoral varus (DFV) correction with interlocking nails requires bone-implant interface stability during nail insertion. Current cancellous reaming techniques may fail to provide adequate prelocking nail stability within its metaphyseal tunnel. Subsequent intraoperative loss of reduction may result in incomplete varus correction and patellar re-luxation. While cancellous compaction has been shown to improve screw fixation, its benefits in DFV correction are unknown. Therefore, our study evaluated the effect of cancellous compaction on the immediate bone/nail interface stability using a cancellous bone model. We hypothesized that, compared with reaming, cancellous compaction would increase immediate bone/nail interface stability. Materials and Methods: Synthetic bone models were fabricated using 12.5 PCF polyurethane foam, n = 5/group. Specimens were prepared using either standard 7 mm reaming or sequential compaction with 4 to 7 mm mandrels. Mechanical testing included mediolateral bending tests on reamed and compacted specimens and impaction stiffness tests for each mandrel size and I-Loc nail in compacted foam samples. MicroCT analysis of three specimens evaluated compaction-induced changes in foam architecture. Results: Compaction increased construct stiffness and load at 5 mm displacement in 12.5 PCF foams ( p < 0.0001). Impaction test showed increasing stiffness and load at 32 from 4 mm mandrel to 7 mm mandrel and I-Loc nail. Micro-CT scan results demonstrated significant differences between drilled and compacted samples with clearly defined and wider dense rings around the central hole in compacted specimens. Discussion/Conclusion: Our study suggests that, compared with conventional reaming, cancellous bone compaction significantly increases immediate, prelocking bone/nail interface stability in a distal femoral osteotomy model. 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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".