Type of Submission
Poster
Campus Venue
Dixon Ministry Center, Alumni Hall
Location
Cedarville, OH
Start Date
4-10-2013 1:00 PM
End Date
4-10-2013 5:00 PM
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.
Apr 10th, 1:00 PM
Apr 10th, 5:00 PM
Mechanical Evaluation of Metal on Metal Total Hip Arthroplasty
Cedarville, OH
Comments
Abstract:
Metal on metal (MoM) total hip arthroplasty describes hip joint replacement where a metal (titanium or cobalt chromium) femoral head articulates against a metal (titanium or cobalt chromium) socket (acetabulum). This implant scenario has generally been successful until more recently when larger (> 36 mm) metal heads have been increasingly used to reduce the incidence of hip joint dislocation. Today, the number of clinical failures (described by fretting corrosion) of MoM total hip arthroplasty is increasing at alarming rates. The objective of our research is to investigate three potential factors that may lead to fretting corrosion. These factors include the horizontal lever arm (HLA), the length of taper engagement, and the trunnion manufacturing tolerances. We hypothesize that a combination of these factors is creating a state of stress and unacceptable motion of the femoral head relative to the trunnion that increases wear and leads to undesirable revision rates. We are testing our hypothesis by conducting finite element analysis (FEA) and hip joint experiments with physiological loading. Initial results show that there is a direct correlation between FEA model and experiments. Furthermore, our initial results show that there is a direct correlation between the head size and the stress on the neck of the implant, in that larger diameter femoral heads create a higher state of stress in the neck of the implant. In addition, initial results validate micromotion of the femoral head with respect to the neck.