Abstract
Patient specific implants are becoming viable treatment options in some orthopaedic applications through advances in additive manufacturing and 3D printing techniques. One potential application is for treatment of segmental bone defects, particularly in patients suffering from bone cancer. Current treatment options are: Amputation, megaprosthesis, or allografts. These treatments are often highly invasive, may require a partial/full joint replacement and are limited by mechanical properties, which affect the life of the implant. The Ti6Al4V implant proposed in this research was designed to fit a mid-diaphyseal segmental bone defect, mimic the mechanical properties of bone, facilitate osseointegration and reduce wear at the bone-implant surface. Computer-Aided Designs (CAD) were constructed of patient-specific Ti6Al4V implants based off the geometry of (1) a patient suffering from a lesion on the mid-diaphysis of the femur and, (2) a 4th Generation right Sawbones® femur. Pore size and shape were assessed using Finite Element Analyses (FEA) software. The overall porosity was maximized to develop an implant with an effective elastic modulus equivalent to bone. The two implants were then fabricated using Direct Metal Laser Sintering (DMLS). The geometry of the physical implant was measured and mechanically loaded under compression to validate the computational model. FEA was an effective tool for optimizing the pore size, shape and overall porosity of the implant, which indicated that 1mm circular pores in three orthogonal planes at an overall porosity of 54-76% would produce an implant with an effective elastic modulus equivalent to cortical bone. Geometric analysis of the 3D printed implant indicated the pore sizes were reduced by an average of 16% as compared to the computational model and that there was a correlation between the size and precision of the pore and the orientation of the implant during the additive build. Compression testing of the implants indicated that they had an effective elastic modulus of 20.8 and 10.5 GPa, which is within the accepted values for cortical bone.
Highlights
Osteosarcoma is the most common primary bone malignancy found in children
This study showed that Direct Metal Laser Sintering (DMLS) may lead to a 16% reduction in pore size as compared to the computational design
Additive manufacturing has recently gained a large amount of excitement in the orthopaedic field for a wide variety of disorders, which include segmental bone defects to treat bone cancer as well as total joint arthroplasty
Summary
Osteosarcoma is the most common primary bone malignancy found in children. The most common skeletal sites of disease include the distal femur, proximal tibia and proximal humerus. Osteosarcoma presents at a rate of 5.4 per million per year in males and 4.0 per million per year in females (Vander, 1996). 42% of all osteosarcoma cases originate within the femur, with 75% of tumors occurring in the distal metadiaphyseal region (Ries et al, 1999). The five-year survival rate for osteosarcoma patients is 68% (Vander, 1996; DiCaprio and Friedlaender, 2003; Gibbs et al, 2001)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: American Journal of Engineering and Applied Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
