Patient-Tailored Selective Laser Melt-Fabricated Plates for Repair of Foot and Ankle Pathology

Medshape Solutions, Inc., Atlanta GA

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Abstract

? DESCRIPTION (provided by applicant): The objective of this project is to develop novel, patient-specific, geometrically complex, Titanium (Ti) alloy plates made by additive manufacturing (AM, also called 3D-printing) for foot and ankle applications. These plates will offer superior fixation and mechanical performance, while minimizing the plate bulk volume. Foot and ankle surgeries are common, where over 200,000 are performed each year in the U.S. for bunion repair alone. The market for extremity fracture repair is expected to reach $4.5 Billion annually by 2017. Current plates for foot and ankle repair are simple with mainly two-dimensional geometries, which do not conform well to the complex anatomy of the bones in the foot and ankle. Therefore, surgeons spend time bending plates to fit patient anatomy, which does not always guarantee sufficient fixation. The proposed AM-created plates with tailored architectures will promote superior stability by improving fit, maintaining strength, reducing profile, and reducing cost. By using the AM technique of selective laser melting of Ti alloy, the geometry can be tailored to the patient anatomy, which will achieve better fit and reduce surgery time. Complex architectures, such as pores, internal channels, and thin-walled sections, will aid in bone growth, optimization of mechanical properties, and reduction of soft tissue irritation. Channels can also serve as attachment points for suture or graft material. In addition, the use of AM plates decreases costs associated with traditional manufacturing where molds and tooling would need to be changed between patients. This proposed project will be accomplished through three specific Aims. Aim 1 will tailor the design of patient-specific F&A plates featuring complex 3D features through finite element analysis (FEA) of models based upon anatomic imaging. This Aim will be achieved by creating 3D models of devices based upon cadaveric foot anatomic imaging and evaluating the models' performance under multiple clinical loading scenarios. Aim 2 will assess the designs from Aim 1 by comparing AM-created plates and traditionally manufactured plates for mechanical performance and production efficiency. This Aim will determine the production cost, time, and waste for each method and compare the mechanical performance under monotonic and cyclic loading regimes. Aim 3 will evaluate the fit and mechanical performance of AM-created plates for specific pathologies in the cadaveric foot specimens imaged in Aim 1. This Aim serves to validate the prior Aims by producing AM-created plates to fit complex bones with varying pathologies. The plate to bone apposition and mechanical performance will be evaluated by micro-CT and mechanical testing, respectively. The successful completion of Phase I will demonstrate novel, patient-tailored, AM-created plates for treating foot and ankle pathologies that can sustain load-bearing conditions. These plates will enhance fixation and stability, leading to improved clinical healing and fusion.