Hoag Bone Plate Fixation Project

Background 

When a fracture in a bone occurs, bone plates are used to facilitate the healing of the bone. Orthopedic surgeons attach these plates directly onto the bones of the patients. However, there have been a number of documented cases where the bone plate ends up failing, causing damage and requiring additional surgeries for the patient. When bone plates shift, there is micromotion and shearing between the bone and the metal plate, which compromises the stability of the plate. With the assistance of Professor McCarthy and Hoag Orthopedics, testing of the new re-designed textured metal plates will be conducted to analyze the improvement in the interface between the bone and the plate.

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Goal and Objectives

The ultimate goal of our project is to physically prove that a textured bone plate has a significantly greater coefficient of friction with the surface of a bone than a smooth bone plate. We aim to achieve this goal by performing tensile testing and dynamic testing on both smooth bone plates and textured bone plates. First, our team will test plastic, 3D-printed bone plates on PVC pipes to document our testing procedures and ensure no problems arise. Then, our team will order stainless steel metal plates and receive an order of medical-grade sawbones from Hoag Orthopedics. We will perform our final tests with these plates and sawbones as detailed below:

• Tensile Testing: (measuring displacement v. applied force)
  - 10 six-hole (full) smooth stainless steel plates mounted on fractured sawbone
  - 10 six-hole (full) textured stainless steel plates mounted on fractured sawbone
• Dynamic Testing: (measuring cycles to failure v. applied force)
  - 10 pairs of 1-hole smooth stainless steel plates mounted on sawbone sample
  - 10 pairs of 1-hole textured stainless steel plates mounted on sawbone sample

With the data we collect from these two tests, we will be able to determine whether the textured bone plates designed by our team are an improvement over the standard smooth bone plates.

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Current Status

Tensile Testing:

• Completed for both smooth plates and textured plates - final data is shown in figures 1 and 2 below:

Figure 1: Tensile Testing Results for Smooth 6-Hole Plates

Figure 2: Tensile Testing Results for Textured 6-Hole Plate

Dynamic Testing:

• Completed for both smooth plates and textured plates - data is still being compiled and analyzed. Current data shows significant difference in friction force produced by textured plates vs. smooth plates.

Figure 3: Dynamic Testing Results - Comparison between Textured and Smooth 1-Hole Plates

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Official Team Website

Hoag Bone Fixation (uci.design)

Team Contacts

Adam D. Klaes / aklaes@uci.edu

Fidel Lopez / lopezfs@uci.edu

Team Advisor & Sponsors

Dr. J. Michael McCarthy / jmmccart@uci.edu

Teddy Quilligan / edward.quilligan@hoagorthopedics.org

Vance Gardner / vogardner@gmail.com