Custom fabrication of a composite hemi‐knee joint based on rapid prototyping

Abstract

Purpose

To present a custom design and fabrication method for a novel hemi‐knee joint substitute composed of titanium alloy and porous bioceramics based on rapid prototyping (RP) and rapid tooling (RT) techniques.

Design/methodology/approach

The three‐dimensional (3D) freeform model of a femur bone was reconstructed based on computerized tomography images via reverse engineering and the 3D reconstruction accuracy was evaluated. The negative image of artificial bone was designed with interconnected microstructures (250‐300 μm). The epoxy resin mould of a hemi‐knee joint and the negative pattern of an artificial bone were fabricated on Stereolithography apparatus. Based on these moulds, a titanium‐alloy hemi‐knee joint and a porous‐bioceramic artificial bone were created by quick casting and powder sintering (known as RT) techniques, respectively. After assembling, a composite hemi‐knee joint substitute was obtained.

Findings

The 3D reconstructed freeform model of the femur bone conformed to the original anatomy within a maximum deviation 0.206 mm. The sintered artificial bone had interconnected micropores (250 μm) and microchannels (300 μm). After implanting in vivo, the composite hemi‐knee joint substitute matched well with the surrounding tissues and bones with sufficient mechanical strength.

Research limitations/implications

Further in‐vivo research is needed to provide the evidence for tissue growth into the ceramic structures and long‐term viability and stability of the implant.

Originality/value

This method enhances the versatility of using RP in the fabrication of tissue‐engineered substitutes, especially when individual matching is considered. Although this paper took a customized hemi‐knee joint substitute as an example, it is capable of fabricating other artificial substitutes with a variety of biomaterials.

Citation

He, J., Li, D., Lu, B., Wang, Z. and Zhang, T. (2006), "Custom fabrication of a composite hemi‐knee joint based on rapid prototyping", Rapid Prototyping Journal, Vol. 12 No. 4, pp. 198-205. https://doi.org/10.1108/13552540610682705