Date of Award

5-2013

Degree Name

MS in Biomedical Engineering

Department

Biomedical and General Engineering

Advisor

Scott Hazelwood

Abstract

With more young adults requiring total hip

arthroplasties the need for bone saving implants becomes

more important. The Zimmer Fitmore is a new bone saving

implant that utilizes an implantation technique that

reduces the damage to the muscle tissue allowing for

patients to have a short recovery time as well as a new

design that allows it to rest on the medial cortex. There

has been anecdotal evidence that this device leads to early

revision within six months of implantation due to failures

occurring in the medial cortex. The main goal of this

study was to computationally model the Zimmer Fitmore and

compare it to the ML Taper to see if the failures are due

to the design of the implant. The models were created

using CT scans of the implants and the same implantation

process was simulated for each. Two sizes for the cortical

bone thickness, 4mm and 10mm, were used and contrasted with

each other. The 10mm cortical thickness model showed that

v

the strains experienced by the Zimmer Fitmore femur were

higher than that of the ML Taper. The 4mm model did not

fully complete the simulation, but the results that were

obtained showed an increased strain in Gruen zone 7. These

results show that the design, not implantation method,

could be to blame for the need for early revision when

using the Zimmer Fitmore.

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