Intelligent anatomic design of porous radial head prosthesis and microscopic-macro biomechanical finite element analysis in the long-term after replacement surgery.

BACKGROUND

The microporous structure of porous titanium alloy may affect osteoblast differentiation and reduce effective elastic modulus (EEM) of the prostheses. Therefore, the biomechanics-based anatomic design of porous radial head prosthesis (PRHP) may help promote bone healing and reduce postoperative complications.

METHODS

A microscopic-macro virtual testing platform (VTP) was built to design cells with excellent mechanical properties, further, to construct the PRHP. An intelligent anatomic platform of healthy human elbow-forearms was developed to construct finite element (FE) models of solid radial head prosthesis (SRHP) and PRHP replacement for Mason type III fractures. Axial and valgus loads were applied for surgical model validation and microscopic-macro biomechanical analysis.

RESULTS

The order of ultimate compressive load (UCL) and yield strength (YS) of five types of cells is NEWTET>KAGOME>NEWPYRAMID>TET>PYRAMID. Under the same porosity conditions, UCL and YS of the double and four-layer lattice structures of NEWTET decreased by 62.39 %, 69.46 % and 61.70 %, 70.21 % compared to the single-layer, respectively. The EEM of NEWTET-based PRHP is 17.66 % of that of SRHP. Compared with the SRHP replacement, PRHP replacement reduced the humeral cartilage stress by 18.96 %-19.51 %.

CONCLUSIONS

NEWTET cell has better microscopic mechanical properties and bone-growth adaptability. The EEM of NEWTET-based PRHP closely resembles cortical bone. Compared with SRHP replacement, microscopic-macro biomechanical performance in long-term after PRHP replacement is closer to that of a normal elbow joint. The microscopic-macro VTP and human intelligent anatomic elbow-forearm FE analysis systems provide efficient, accurate, and smart tools for the design of porous prostheses in joint replacement surgery.