3D Printing a Bio-Polymer Cap for the Articular Femoral Condyles: A Feasibility Study

摘要

With approximately 12% of adults in the United States affected by osteoarthritis (OA), constant research is being performed to advance treatment techniques for this ailment. 3D printed bio-polymer caps have been proposed as a potential treatment for severe cases of OA, and are an alternative to traditional implants. This report considers the feasibility of one such bio-polymer cap using a simplified, linear, finite element analysis (FEA) model. Material properties for both Bionate 80A and articular cartilage are considered for comparison. The simulation modeled joint loading for a 195 lb, 867.4 N, adult male squatting from 0 to 90-degrees flexion with a mathematical model governing the changing contact area on the medial and lateral condyles. Menisci effects were neglected as a part of the model reduction. For Bionate 80A, minimum and maximum stress values of 1.124 MPa and 3.555 MPa were obtained, with corresponding deflections of 126.8 urn and 316.8 μm. The articular cartilage model gave stress values of 1.102 MPa and 3.623 MPa, with deflections of 170.2 urn and 420.8 μm. A maximum shear stress value of 1.988 MPa was obtained in the Bionate 80A simulation. From these results, it was determined that the Bionate cap is comparable to articular cartilage and could be a viable replacement in the cases of advanced OA, but the Bionate cap may have limitations on joint flexibility due to the relatively small 1.65 factor of safety at 90-degree. The maximum shear stress value indicates it would be viable to use specific biocompatible cements as a method of fixture.