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Time-elapsed microstructural imaging of failure of the reverse shoulder implant.
- Source :
- Journal of Orthopaedic Surgery & Research; 3/12/2024, Vol. 19 Issue 1, p1-12, 12p
- Publication Year :
- 2024
-
Abstract
- Background: Reverse Shoulder Arthroplasties (RSA) have become a primary choice for improving shoulder function and pain. However, the biomechanical failure mechanism of the humeral component is still unclear. The present study reports a novel protocol for microstructural imaging of the entire humerus implant under load before and after fracture. Methods: A humerus specimen was obtained from a 75-year-old male donor. An expert surgeon implanted the specimen with a commonly used RSA implant (Aequalis reversed II, Stryker Orthopaedics, USA) and surgical procedure. The physiological glenohumeral contact force that maximized the distal implant migration was selected from a public repository (orthoload.com). Imaging and concomitant mechanical testing were performed using a large-volume micro-CT scanner (Nikon XT H 225 ST) and a custom-made compressive stage. Both when intact and once implanted, the specimen was tested under a pre-load and by imposing a constant deformation causing a physiological reaction load (650 N, 10 degrees adducted). The deformation of the implanted specimen was then increased up to fracture, which was identified by a sudden drop of the reaction force, and the specimen was then re-scanned. Results: The specimen's stiffness decreased from 874 N/mm to 464 N/mm after implantation, producing movements of the bone-implant interface consistent with the implant's long-term stability reported in the literature. The micro-CT images displayed fracture of the tuberosity, caused by a combined compression and circumferential tension, induced by the distal migration of the implant. Conclusion: The developed protocol offers detailed information on implant mechanics under load relative to intact conditions and fracture, providing insights into the failure mechanics of RSA implants. This protocol can be used to inform future implant design and surgical technique improvements. [ABSTRACT FROM AUTHOR]
- Subjects :
- BIOMECHANICS
MEDICAL protocols
PROSTHETICS
BONES
COMPLICATIONS of prosthesis
RESEARCH funding
COMPUTED tomography
TREATMENT effectiveness
ARTIFICIAL implants
BONE fractures
SURGICAL complications
INTERNAL fixation in fractures
REVERSE total shoulder replacement
SHOULDER joint injuries
TIME
RANGE of motion of joints
Subjects
Details
- Language :
- English
- ISSN :
- 1749799X
- Volume :
- 19
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Journal of Orthopaedic Surgery & Research
- Publication Type :
- Academic Journal
- Accession number :
- 176005842
- Full Text :
- https://doi.org/10.1186/s13018-024-04652-9