The most prominent fracture to the distal radius is a Colles’ fracture. The healing time for a Colles’ fracture is approximately six to eight weeks. However, 5-10% of Colles’ fractures experience non-unions, healing defects that hinder healing by preventing the two ends of the fracture from joining to form a callus. To monitor the progression of a fractured wrist, doctors use radiographs and other imaging techniques to measure the reduction of the fracture line. Currently, there is no way to quantify the extent of bone healing. We have a novel device that applies a non-damaging bending load to a healing distal radius fracture, while simultaneously recording the applied force. The prototype device utilized a drive-screw mechanism to apply a compressive force to the patient’s wrist and a strain gauge attached to the screw to measure the applied force. Our project goals were to redesign the force application and sensing portions to improve ease of use, to displace a fractured bone 0.25-0.75mm, and increase the radiolucent window by an inch to maximize viewing of a wrist in a CT scanner. We fabricated a pneumatic applicator system with a digital pressure transducer to record data. The force:pressure relationship was calibrated using a materials testing machine and found to be 0.24 N/mmHg. To test our design, two cadaveric wrists with simulated distal radius fractures of varying severity were scanned with a High Resolution Peripheral Quantitative Computed Tomography Scanner (XtremeCT, Scanco, Switzerland), which has a resolution of 164 microns. By comparing these scans, the micro-displacement of the bone can be quantified. Displacement ranged from 0.18- 0.51mm in the distal radius with an applied pressure of 100 mmHg, which correlated to 23.32N of force, ± 0.19N. We conclude that the device produces measurable displacements of bone in a simulated fracture model, and is quick and easy to use. The device will be the first to quantify the integrity of healing fractures for faster nonunion diagnosis, reducing potential extended treatment. This device also has potential applications in clinical trials to quantify the effects drugs have on bone healing

• This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.

Creator

• Witkin, Alex Joshua
• McLarnon, Julie Marie
• Amirault, Daniel P
• Caron, Maddison Marie

Publisher

• Worcester Polytechnic Institute

Identifier

• E-project-042518-224416

Advisor

• Troy, Karen

Year

• 2018

Date created

• 2018-04-25

Resource type

• Major Qualifying Project

Major

• Biomedical Engineering

Rights statement

• In Copyright