[Fabrication of custom-made artificial semi-knee joint based on rapid prototyping technique: three-dimensional reconstruction of femoral condyle]

Abstract

Objective: To achieve three-dimensional (3D) contour image of bone and articular cartilage for fabricating custom-made artificial semi-knee joint as segment bone allograft.

Methods: The distal femora of human and pig were scanned with Picker 6000 spiral X-ray computed tomography with 1.0 mm thick slice. The data obtained were treated in Voxel Q image workstation for 3D reconstruction with volume rendering technique. After being downloaded to personal computer at 0.1 mm interval, the transaxial 2D image data were converted into 2D digitized contour data by using image processing software developed by the team. The 2D digitized data were inputted into image processing software of Surfacer 9.0 (Imageware Company, USA), then the 3D wire frame and solid images of femoral condyle were reconstructed. Subsequently, based on the clinical experience and the requirement of the design of artificial knee joint, the 3D contour image of bone or articular cartilage was extracted from the surrounding.

Results: The 3D contour image of bone or articular cartilage presented was edited and processed easily for the computer aided design (CAD) of custom-made artificial knee joint.

Conclusion: The 3D contour image of bone and articular cartilage can be obtained by spiral CT scanning, and the digitized data can be applied directly to CAD of custom-made artificial joint and subsequently rapid prototyping fabricating. In addition, the reconstruction method is simple and can be applied widely to clinical implant fabricating practice of dentistry and orthopaedics.