Biomechanical Analysis of Newly Developed Local Hip Implant from Stainless Steel, Cobalt-Chrome, and Titanium Materials Using the Finite Element Method

International Journal of Biomedicine 15(4) (2025) 700-703 http://dx.doi.org/10.21103/Article15(4)_OA9 ORIGINAL ARTICLE INTERNATIONAL JOURNAL OF BIOMEDICINE Orthopedics Biomechanical Analysis of Newly Developed Local Hip Implant from Stainless Steel, Cobalt-Chrome, and Titanium Materials Using the Finite Element Method Hantonius1,2, Kukuh Dwiputra Hernugrahanto1,2, Fahmi Mubarok3, Dwikora Novembri Utomo1,2* Department of Orthopaedics and Traumatology, Faculty of Medicine, Universitas Airlangga, Surabaya, Indonesia 2 Department of Orthopaedics and Traumatology, Dr. Soetomo General Academic Hospital, Surabaya, Indonesia 3 Department of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia 1 Abstract Background: Total hip arthroplasty (THA) is one of the most successful health interventions in the last century. However, there have been several reports of dissatisfaction with the hip implant. Most modern implants are manufactured based on Western morphology. This generalized design may not be suitable for all races, particularly Asians, who tend to have a more petite physique and distinct femoral anatomy. Methods and Results: This study evaluated the biomechanical properties of a newly developed local hip implant using the Finite Element method based on ISO 7206-4, ISO 7206-6, and ASTM F2996-20. The implants were analyzed under static and dynamic load, and three different implant materials were used. The results showed that the titanium (Ti6Al4V) implant had the lowest von Mises stress, the cobalt-chrome (Co28Cr6Mo) implant had the lowest total deformation, and the stainless steel (SS316L) implant had the highest alternating stress and a lower life cycle. All of the materials have more than 1 (>1) safety factor value, which is considered safe for implant manufacturing. Conclusion: This study offers insights into the performance of various materials under static and dynamic loading conditions, demonstrating that all simulated materials are deemed safe for implant manufacturing.(International Journal of Biomedicine. 2025;15(4):700-703.) Keywords: biomechanical analysis • hip implant • finite element method For citation: Hantonius, Hernugrahanto KW, Mubarok F, Utomo DN. Biomechanical Analysis of Newly Developed Local Hip Implant from Stainless Steel, Cobalt-Chrome, and Titanium Materials Using the Finite Element Method. International Journal of Biomedicine. 2025;15(4):700-703. doi:10.21103/Article15(4)_OA9 Introduction Total hip arthroplasty (THA) is a surgical procedure that has a significant impact on restoring the function of damaged hip joints and is one of the most successful health interventions in the last century.1 Presently, hip joint arthroplasty has a 10year success rate and 95% survivorship for patients older than 70 years.2 However, despite the long-term stability and functionality of the Total Hip Replacement system, a 7% rate of dissatisfaction was observed after the THA operation.3 The configuration of the prosthesis has been recognized as a crucial determinant of the contact condition between the implant and the bone. Most modern implants are manufactured based on Western morphology and surgical standards.4 This generalized design template may not be adequate for all races, especially Asians, who are reported to have a more petite physique and possess smaller femoral anatomy compared to Caucasians.5 Institut Teknologi Sepuluh Nopember (ITS), in collaboration with the Orthopaedic Department of Dr. Soetomo Hospital, has developed a locally manufactured Indonesian hip implant (ORTHOHITS), whose design is tailored to the Mongoloid race, with a neck offset and neck length shorter than those of European brands. This implant is expected to offer more precise anatomical accuracy and improved biomechanics for Indonesians compared to European brands. Hantonius et al. / International Journal of Biomedicine 15(4) (2025) 700-703 Currently, there are no other locally made Indonesian hip implants available.6 Biomechanical testing is a critical component in implant development, as it not only measures durability but also ensures that the implant can function optimally under realistic physiological conditions after several years of use without failure.7 Numerous studies comparing experimental fatigue data with fatigue life simulation analysis have demonstrated that Finite Element Analysis (FEA) can accurately depict the true stress variations of the hip implant.8-10 This study aimed to evaluate the biomechanical performance of ORTHOHITS, a newly designed hip implant adjusted for the Mongoloid race by FEA. A total of three implant materials were analyzed using Finite Element models. Methods This study compares the biomechanical properties of titanium (Ti6Al4V), cobalt-chrome (Co28Cr6Mo), and stainless steel (SS316L) hip implants created locally. The test was done in accordance with ISO 7206-4, ISO 7206-6, and ASTM F2996-20 standards to provide guidance to implant designers during the FEA process for hip implants.11-13 The ORTHOHITS hip joint implant design (Figure 1) was used in this work’s geometrical analysis. Materials used in this investigation were stainless steel (SS316L), cobaltchrome (Co28Cr6Mo), and titanium (Ti-6Al-4V). 701 geometries and numerical solutions to highly complicated stress problems.14 The commercial program Ansys Workbench 2021 R1 was used to generate the FEA model. Three-dimensional tetrahedron meshing was used because this method offers flexibility, allowing tetrahedral elements to be used to unite three-dimensional volumes regardless of their shape or topology. The optimal mesh size was estimated, and the highest von Mises stresses remained constant between 3 and 1 mm of mesh size. We used a 2 mm mesh size for rapid, precise, and reliable simulation; the total elements and nodes from the 2 mm mesh size are 15.565 and 27.388. According to ASTM F2996-20, ORTHOHITS hip joint implant boundary condition is 90 mm from the head’s center because the length of the prosthesis ranges between 120-15 0mm. Figure 2 shows the boundary conditions for the ORTHOHITS hip joint implant simulation.13 Figure 2. Positioning of the THA implant during simulation. Figure 1. ORTHOHITS hip implant design. The prototype implant presented in this study is a newly designed, collarless, cemented hip implant featuring a trapezoidal shape in the proximal region and a rounded stem region. Its purpose is to transmit the principal stress applied to the bone, which is an important factor for maximum principal stress distribution. The ORTHOHITS hip joint implant stem length is 130mm with neck offset 35 mm, neck length 33.6 mm, neckshaft angle 135-degrees, and distal stem diameter 5.4 mm. The design is based on a standard European THA brand but with 3mm shorter neck offset, 2-3 mm shorter neck length and 1.5 mm smaller stem diameter. The femoral head size is 32 mm. The analysis method employed in this study is FEA using ANSYS Static Structural sof (...truncated)