Design, manufacture, and fatigue analysis of lightweight hip implants

Abstract

Background: This study aims to design, analyze and manufacture lightweight hip implants which have sufficient fatigue performance to enable use in total hip arthroplasty (THA). Methods: The lattice structure was applied on an implant geometry, which is frequently used in THA, to provide a reduction in mass and increase flexibility. The implant surfaces were roughened using semispherical pores to improve the osseointegration. The specimens were manufactured by means of direct metal laser sintering (DMLS) and fatigue tests were performed according to ISO 7206-4:2010. Moreover, fatigue analyses of the designed implants were numerically carried out using the finite element method. Results: The applied lattice structure on implant geometry leads to 15-17% reduction in the masses of implants compared to a solid one. It has also been determined that the lightweight implants show more flexible behavior with increasing pore diameter used on the implant surfaces while keeping the lattice structure geometry constant. The fatigue test and finite element analysis (FEA) results are in reasonable agreement. In addition, additively manufactured solid implants have exhibited similar fatigue performance with one produced by conventional methods. Conclusions: This paper presents design, analysis, manufacturing and fatigue test processes of lightweight hip implants. The lattice structure and the semispherical pores were applied on a reference implant geometry and they were manufactured by DMLS. The fatigue tests and FEA were performed to evaluate newly designed implant performance. All the implants successfully completed the fatigue tests without any damage.

Design, Optimization, and Evaluation of Additively Manufactured Vintiles Cellular Structure for Acetabular Cup Implant

“…Maximum VM stresses and high displacement occur in the upper region of all cellular implants. These results show that it is similar to the ones introduced by Sivasankar et al and Delikanli et al [59,60]. As shown in Table 5 and Figure 9, the less porosity cellular implant (optimized) contains the smallest maximumVM stresses (533.81 MPa) compared to the higher porosity cellular implant.…”

Análise da deformação na prótese femoral não cimentada do quadril pelo método de elementos finitos – Influência da variabilidade do posicionamento angular do implante

“…In 2019, Chethan et al 15 used FEM to study the static physical structure of several models of femoral nails and acetabular components for THA and concluded that the trapezoidal femoral components suffer less strain; ceramic acetabular inserts, on the other hand, showed better mechanical properties under load. Finite element method was validated as an alternative method to traditional physical tests on hip prostheses by Delikanli and Kayacan 16 in 2019; their study compared the behavior of a titanium femoral stem under load in a physical model and FEM, with similar results.…”

Additive manufacturing structural redesign of hip prostheses for stress-shielding reduction and improved functionality and safety

“…Another AM design was proposed by Delikanli et al in 2019. A solid lattice structure with variable sizing in the inner part and semi-spherical pores in the outer region was modelled and manufactured [14]. A reduction of 15-17% of the implant mass was obtained and the proposed manufacture reports enough fatigue performance according to the requirements of the ISO 7206 standard.…”