Poster AA2 - Arthritis Knee Rehab Device

Introduction: Unicompartmental arthritis of the knee is an orthopedic degenerative disorder characterized by abnormal articular cartilage in either the medial or lateral compartment of the tibiofemoral joint. The objective of this project is to develop an off-loading brace aimed at reducing pressure on the arthritic side of the knee, thereby promoting cartilage regeneration, minimizing discomfort, and alleviating pain. The design of the knee brace will be accomplished using SolidWorks software and will undergo testing on patients utilizing Plantar Pressure analysis, EMG (Electromyography), and 3D Motion Gait Analysis systems.

Materials and

Methods: Gait patterns, joint angles, and EMG signals were assessed before brace implementation using Noraxon Software. We found our patient had a greater knee abduction and knee external rotation than the average population, which was a cause for medial osteoarthritis.
To have exact measurements of our patient’s leg, we created a mold of her knee. First, we casted our patient using rolls of casting plaster. After letting it dry and harden, we cut the cast off the leg with an oscillating saw. The cast was sealed on the sides and bottom, and plaster was poured into the top of the cast to create the mold of our patient's leg. Once the plaster inside hardened, the cast was removed. The mold of the leg was then used to drop into polypropylene which serves as the outer covering of the knee brace.
Using the 3D CAD software SolidWorks, we created two hinges for the knee brace. One hinge applies pressure to the lateral side of the knee to off-load the medial compartment. A spring hinge was created to absorb the force on the knee to relieve pressure. These hinges were cut out in the CNC machine and implemented in the overall knee brace design. They connected to the polypropylene with rivets when putting the brace together. Velcro straps and D-rings were connected to the brace during the final step.

Results, Conclusions, and Discussions: After 5 months of building the knee brace, the first prototype was completed. Our next steps in our project is to test the brace on our patient and continually modify the brace to make improvements. We will have our patient wear the brace throughout the day and have her report the length of use, level of satisfaction, and pain reductions. After continual use, we will use the Noraxon Gait Analysis Software to gather the patient’s new data and compare it to the data before implementation of the brace. We will also use data of the normal population to compare to our patient’s gait analysis.

Acknowledgements (Optional): We would like to thank Dr. Vo for supporting and advancing our project and Trung Le for teaching us how to use the 2D and 3D Gait Systems in the Gait Lab. We would also like to thank Kerr Griffin for teaching us how to use the machines and equipment in the Prosthetics Lab and guiding us on our project.