Spherical center and rotating platform hinged knee prosthesis: Finite-element model establishment, verification and contact analysis

Biomechanical study is fundamental for the preclinical evaluation of knee prostheses. However, there are few reports on the contact characteristic investigation in the hinged knee prosthesis. The purpose of this study was to investigate the contact characteristics of a novel hinged knee prosthesis.

All of the component models were designed and assembled using Solidworks. A comparison of the contact area and ultra-high-molecular-weight polyethylene (UHMWPE) deformation using the experimental method (EM) and finite-element analysis (FEA) under 3000 N with the prosthesis at different flexions was performed. The peak contact pressure and von Mises stress on tibial insert and bushing were investigated under nine specific samples that were extracted from a gait cycle using FEA (according to ISO 14243-1: 2009).

The largest contact area and UHMWPE deformation were 100.78 ± 8.71 mm ² and 0.085 ± 0.015 mm in the EM, and 96.68 mm ² and 0.096 mm in FEA. The peak contact pressure and von Mises stress on the tibial insert were 26.3071 MPa and 10.5115 MPa at 13% of the gait cycle and on bushing were consistently 0 MPa. The contact pressures were distributed at the posterior of the insert.

The finite-element model was validated to be applicable for predicting the real prosthesis behavior based on the good correlation of the results using the EM and FEA. The model can help to identify contact characteristics and be can used in optimization studies of this novel prosthesis during the design phase.