Taper-Trunnion Interface Stress Varies Significantly With Head Size and Activity
| Autor: | Thomas A. Fehring, Devan M. Kienitz, Austin J. Land, Jordan E. Denen, Timothy L. Norman |
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| Rok vydání: | 2018 |
| Předmět: |
Head size
Male Reoperation Arthroplasty Replacement Hip Finite Element Analysis Biocompatible Materials Femoral stem Prosthesis Design 03 medical and health sciences Femoral head 0302 clinical medicine Stress Physiological medicine Humans Orthopedics and Sports Medicine Femur Morse taper Orthodontics Titanium 030222 orthopedics Hip joint dislocation business.industry Femur Head Prosthesis Failure Corrosion medicine.anatomical_structure Metal-on-Metal Joint Prostheses Trunnion Chromium Alloys Hip Prosthesis Stress Mechanical business A titanium Total hip arthroplasty |
| Zdroj: | The Journal of arthroplasty. 34(1) |
| ISSN: | 1532-8406 |
| Popis: | Background Total hip arthroplasty is performed with modular parts. Either a metal or ceramic ball is fastened to the trunnion of a femoral stem via a Morse taper. This implant scenario has been successful. However, recently larger (36 mm or greater) metal heads have become more popular as a means to reduce the incidence of hip joint dislocation. Today, a number of clinical failures have occurred due to mechanically assisted crevice corrosion at the head (taper) stem (trunnion) interface necessitating revision surgery. The objective of this research is to investigate how trunnion stress varies with head size, and how taper-trunnion geometric parameters including horizontal lever arm (HLA), taper engagement level, and a new parameter called trunnion load offset affect trunnion stresses. We hypothesized that trunnion stress may increase with increasing head size and HLA. Methods This hypothesis was tested by conducting finite element analysis of a titanium hip stem and 4 commercially available cobalt-chromium femoral heads subjected to 4 different moderate to severe physiological loading conditions. Results Results showed that trunnion stress increases with increasing head size, increased HLA, and trunnion load offset. It was also found that under certain load cases the trunnion stresses get exceptionally high, especially for the larger head sizes. Conclusion This study suggests trying to avoid larger femoral head sizes that may result in higher implant stresses under certain loading conditions. |
| Databáze: | OpenAIRE |
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