AN APPROACH TO EXAMINE THE EFFECT OF TAPER ANGLE AND THREADING ON PERIPROSTHETIC BONE REMODELING FROM BONE-ANCHORED AMPUTATION PROSTHESES
Bibliographic record
Abstract
INTRODUCTION The most common problems experienced by transfemoral amputees using socket prostheses are soft tissue pain and a limited range of motion around the hip joint [1]. Recently, intraosseous transcutaneous amputation prostheses (ITAP) have been developed as an alternative to the standard socket prostheses for amputees. A current shortcoming of ITAP is the change in the local mechanical loading at the bone-implant interface leading to bone resorption. The clinical consequences of this bone loss are increased risks of bone fracture and implant loosening [2]. The purpose of this study was to develop a finite element modeling approach to examine the effect of ITAP fixture threading and taper angle on femoral bone remodeling. METHODS An intact femoral geometry was generated using Mimics software (Materialise, Leuven, Belgium) from CT scans obtained from the VAHKUM database [3]. Twelve ITAP (six threaded and six unthreaded) implants of varying taper angles were designed using SolidWorks (Waltham, MA). Implants were registered and aligned within the femoral diaphysis, and the implant-femur assembly was meshed with quadratic tetrahedral elements; elements at the bone-implant interface shared identical nodes to represent full osseointegration. Bone elements were assigned inhomogeneous linear-elastic material properties based on CT Hounsfield units. Implant material was modeled as titanium alloy Ti6Al4V ( E =114 GPa, ν =0.3), which is commonly used for prostheses due to its superior strength and biocompatibility. Boundary conditions and loads applied to the finite element models were taken from Tomaszewski et al. [4], which were linearly scaled to correspond to an individual with a mass of 70.1 kg and a height of 170 cm. All models were solved using ABAQUS Standard v6.1 (Providence, RI). Strain energy density was calculated for each implanted femur and compared to those of an intact femur. RESULTS Considerable energy was transferred to the ITAP (Figure 1). Consequently, the periprosthetic cortical bone in the implanted femur had a significantly lower strain energy density than that of the intact femur (Figure 1). DISCUSSION AND CONCLUSIONS It is critical that implant geometry is optimized to decrease periprosthetic bone resorption and reduce the incidence of bone fracture and implant loosening. Changes in strain energy density following prosthetic implantation is a driving stimulus for bone remodeling, and our future work will incorporate adaptive bone remodeling algorithms into our simulations.
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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 | 0.000 |
| Bibliometrics | 0.001 | 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".