Detaillierte Beitrags-Information
| Beitragstitel | Redesigning commercial total hip replacement instruments: an educational project |
|---|---|
| Beitragscode | P117 |
| Autoren | |
| Präsentationsform | Poster |
| Themengebiete |
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| Abstract |
Introduction Commercially available surgical instruments pass a strict certification process. In arthroplasty of large joints, the instruments are persistently exposed to significant mechanical stresses that can potentially lead to fatigue failure. In this educational project, we addressed a very rare case of fracture of the connection pin between femoral broach and handle. The specific aims were (1) to characterize the stress distribution to which the pin is exposed during surgery, (2) to design new connection mechanisms, which are more resistant to fatigue yet do not interfere with the surgical technique. Methods Biomechanics Master students from EPFL were presented with the case of pin failure in a CORAIL® broach. The pin was fractured during removal of the broach, which was then stuck in the femoral canal and required a long procedure to retrieve. The students were asked to study the mode of failure and to propose alternative designs. They were invited to attend surgeries with the CORAIL system to better understand the context. Using computer assisted design and finite element modeling (FEA), they simulated stress patterns around the pin under surgically realistic loads to locate stress risers. They designed new pins that would eliminate stress risers, and validated them by FEA under similar loading conditions. Results Stress risers were identified at the notch level in the current pin design. FEA simulations were in accordance with the actual fracture pattern. Alternative pin designs with axial symmetry instead of unilateral notch were conceived, that would reduce peak stresses to safe levels. The other instruments were redesigned accordingly. An original idea was to add a safety thread in the broach for rescue in exceptional failures. The new designs were considered excellent by a panel of experts. Conclusion Pin failure was post hoc predictable based on FEA. Alternative pin designs appear to be more reliable, but clinical studies are needed to evaluate their pertinence in daily practice. Educational projects, such as this one, where engineering students work on a clinical case and have the opportunity to attend surgeries are beneficial for all parties. Students can express their creativity, exert their theoretical knowledge on real world problems and experience what a career in biomedical engineering might be. Clinicians benefit from by being exposed to new technologies, and in the best case, receive original solutions to their clinical problems. |