Development of a Dynamic Compression Fusion Device for Lower Extremity Salvage of the Diabetic Foot
Abstract
This technology development proposal is directly applicable to the Topic Area of Diabetes, specifically the Area of Encouragement on interventions to treat diabetes complications, like Charcot foot. Charcot foot is a painless, progressive, destructive degenerative disease of the bones in the middle of the foot. The bones typically fracture and dislocate, which causes a collapse of the arch of the foot. A patient may continue to walk on this deformity because they have lost sensation in their foot. Thus, the collapsed bones can wear through the skin of the bottom of the foot, creating an open wound that often leads to infection and possible amputation of the foot. Charcot foot is currently treated by inserting long metal screws through the middle of the bones of the midfoot to align and fuse the bones into a more normal anatomical arrangement, which reduces likelihood of open wound formation at the foot bottom. Unfortunately, these screws fail between 25%-60% of the time because they loosen and break, so they lose the necessary bone-on-bone compression for fusion. The critical problem is that Charcot foot in its nature is a progressive, destructive disease that breaks down the structure of the bones over time. These current screws are static devices, meaning they cannot adapt to any changes in the structure of the bones resulting in loss of bone-on-bone compression. These device failures lead to amputation rates between 5%-24% for patients with Charcot foot, and amputations have a significant negative affect on patient quality of life, in addition to having high lifetime costs. This project aims to improve the treatment of diabetic Charcot foot through development and U.S. Food and Drug Administration (FDA) clearance of a next-generation midfoot fusion device that incorporates a smart metal alloy, nickel-titanium, into the medical device. This alloy can be stretched like a rubber-band and will exert a contractile force as it automatically recovers back to its original length when released. The medical device with a thin internal rod of nickel-titanium will be embedded in the midfoot bones in an elongated geometry, then it will automatically compress the bones together as it tries to return to its original length, even in the face of further deterioration of bone. This automatically adapting, sustained contractile force is essential to having good bone-on-bone contact for joint fusion. By sustaining this bone-on-bone contact, walking forces are more easily transferred through the bones, instead of the device, which prevents the device from breaking during the early healing process. The medical device will be developed with a key focus on both safety and effectiveness, required for FDA clearance of the device and for demonstrating improved function over competitors. Device safety testing will include a variety of mechanical tests such as bending and rotation, both in single and multiple loading cycles, as well as a test to evaluate how much the medical device can compress simulated bones together in the presence of gap formation, as would occur in a Charcot patient when the bones deteriorate. The performance of the medical device will be compared to a competitor’s device that has already been cleared by the FDA for clinical use. The device will also be tested in a sheep foot model to assess if it can improve joint fusion compared with a competing device used currently in the clinic. Sheep with both normal bone and poor-quality bone will be used, as the poor-quality bone will better simulate the condition of a patient with Charcot foot. At both short and long time points following implantation, the joint fusion will be assessed and compared by imaging (X-rays and CT scans), biomechanical testing, and analysis of the amount of bone present at the fusion sites. Successful completion of this project would ultimately lead to a medical device capable of improving outcomes of midfoot fusion for diabetic patien
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010677
Entities
People
- David Safranski
Organizations
- MedShape (United States)
- United States Army