3D-Printing at the Point-of-Care: Patient-Specific PEKK Ankle Fusion Implants for Diabetic Patients
Monday, June 10, 2024
2:00 PM-4:00 PM
BIOMED Master's Thesis Defense
Title:
3D-Printing at the Point-of-Care: Patient-Specific PEKK Ankle Fusion Implants for Diabetic Patients
Speaker:
Pearle Shah, Master's Candidate
School of Biomedical Engineering, Science and Health Systems
Drexel University
Advisor:
Steven Kurtz, PhD
Research Professor
School of Biomedical Engineering, Science and Health Systems
Drexel University
Details:
Failed total ankle arthroplasty (TAA), ankle trauma, or health conditions such as Charcot neuroarthropathy are just a few reasons that may lead to ankle fusion surgeries or ankle arthrodesis. Specifically, diabetes affects 11.6% of the adult U.S. population and has a significant impact on bone health and healing, putting diabetic individuals at a high risk for such surgeries. In one cohort of diabetic patients requiring primary arthrodesis from ankle fractures, an overall complication rate exceeding 75% was found, including issues such as reoperation, infection, non-union, and amputation. Current off-the-shelf ankle fusion cages fail to address the complex anatomies of ankle defects, while customized 3D-printed metal cages pose challenges like metal allergies, cage subsidence, or long manufacturing times. To address complex ankle defect anatomies in diabetic patients and long implant manufacturing times, this study aims to define the design envelope for the development of patient-specific tibiotalar cages using polyetherketoneketone (PEKK) for 3D-printing at the point-of-care (3DP-POC).
A dataset of patient CT scans with a primary cause of death from diabetes was segmented using CT segmentation software (DICOM to Print). Rectangular cages were fitted into each reconstructed anatomical model in Shapr3D based on the boundaries for resection to determine the lower and upper bound cages (extremes of the design envelope). These rectangular cages were refined and customized to fit the exact anatomies of the corresponding patients in Geomagic Freeform. The 3DGence slicing software was then utilized to add porosity and walls to enhance osseointegration and mechanical stability. A high-precision FDM printer, 3DGence Industry F421, was used to print the cages with Kimya PEKK-A filament.
Dimensional analysis, porosity calculations, and static axial compression tests (ASTM F2077) were conducted. All cages fell within the desired printing tolerances of PEKK-A, indicating good dimensional accuracy. A high porosity (>50%) and mechanical stability (>3.6 kN per ASTM F2665) were also achieved. The final cage designs were evaluated by a surgeon who determined their clinical relevance for diabetic patients needing a fusion grid after ankle arthroplasty. This approach strives to shift current clinical standards for ankle fusion surgeries, especially in diabetic patients, through patient-specific 3DP-POC PEKK tibiotalar implants.
Contact Information
Natalia Broz
njb33@drexel.edu