Stemmed Implants Improve Stability in Augmented Constrained Condylar Knees
| Autor: | Russell E. Windsor, Robert F. Closkey, Nicole Davis, Timothy M. Wright, Jeremy J. Rawlinson |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Joint Instability
business.product_category Knee Joint medicine.medical_treatment Dentistry Prosthesis Design Condyle Cadaver Humans Medicine Orthopedics and Sports Medicine Tibia Range of Motion Articular Arthroplasty Replacement Knee Reduction (orthopedic surgery) Aged Orthodontics business.industry Biomechanics General Medicine Middle Aged Wedge (mechanical device) Biomechanical Phenomena medicine.anatomical_structure Symposium: Papers Presented at the Annual Meetings of the Knee Society Surgery Implant business Cancellous bone |
| Zdroj: | Clinical Orthopaedics & Related Research. 466:2639-2643 |
| ISSN: | 0009-921X |
| DOI: | 10.1007/s11999-008-0424-z |
| Popis: | We previously combined experimental and computational measures to ascertain whether tibial stem augmentation reduces bone strains beneath constrained condylar implants. Using these same integrated approaches, we examined the benefit of a stem when a wedge is used. Implants were removed from the eight paired cadaver specimens from our previous experiment, and oblique defects created that were restored with 15 degrees metallic wedges cemented in place. We applied a varus moment and an axial load and monitored relative motion between implant and bone. Specimen-specific 3-D finite element models were constructed from CT scans and radiographs to examine bone stress in the proximal tibia. Implants with a wedge but no stem had greater motion than the previous control with no stem or wedge. Use of a modular stem with a wedge maintained the same level of motion as the primary case, suggesting that a stem is preferable when a wedge is utilized. The computational models confirmed this conclusion with a 30% reduction in bone stress compared to 17% in the primary case without a wedge. The wedge carried more axial load compared to the primary implant due to its support on stiff metaphyseal bone. |
| Databáze: | OpenAIRE |
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