Malaysian team fabricates endoprosthetic hip stem using Metal Injection Moulding

February 23, 2018

Malaysian team fabricates endoprosthetic hip stem using MIM

SIRIM Berhad’s MIM prosthetic hip stem

 

A recently completed research project undertaken by SIRIM Berhad (formerly the Standard and Industrial Research Institute of Malaysia) and the International Islamic University of Malaysia (IIUM) has successfully produced a prosthetic hip stem using Metal Injection Moulding.

The use of Co-based alloys for surgical applications is mainly related to orthopaedic prostheses for the knee, shoulder and hip as well as to fracture fixation devices. Joint endoprostheses (prosthetics which are implanted in the body) must meet extremely high requirements with regards to biocompatibility and corrosion resistance. CoCrMo has been widely used in endoprosthetics due to its mechanical properties, good wear and corrosion resistance and biocompatibility.

Dr Mohd Afian Omar, Principal Researcher, SIRIM Bhd, and colleagues are investigating the use of Metal Injection Moulding for the production of femoral hip stem implants with high surface quality. To manufacture the new implants, the team used CoCrMo alloy metal powder with a median particle size of 15 µm and a binder consisting of palm stearin and poly ethylene, with a powder loading of 65 vol.%.

According to the team, the hip stems were injection moulded using a vertical injection moulding machine with the nozzle temperature of 200°C. The hip stems were then debound using a combination of solvent extraction and thermal pyrolysis method, before sintering under vacuum at 1390°C. The results showed that the highest final sintered densities were about 98% of theoretical maximum value with good mechanical properties, including hardness of 42 HRC, elongation of 10% and UTS of 822 MPa, in line with standard ASTM F75.

To determine the potential toxicity and biocompatibility of the prosthetic, a cytotoxicity test of the hip stem was conducted, in which it was extracted for twenty-four hours in Minimum Essential Medium (MEM), and an extract prepared from the test material then placed on cell monolayers. The cells were examined for morphologic changes, malformation, degeneration and cytolysis to determine a toxicity score.

The cell morphology showed very little change from that of the control specimen, indicating that no morphological abnormalities took place. Cell growth towards the material demonstrated good biocompatibility, particularly on longer incubation times, which also indicated good material-tissue integration. A biomechanical study and preclinical test are expected to be conducted soon.

Email: [email protected]
www.sirim.my

In the latest issue of PIM International…

Download PDF

Extensive MIM, CIM industry and sinter-based AM industry news, plus the following exclusive deep-dive articles and reports:

  • Calling all product designers: Discover what Metal Injection Moulding could do for you through these award-winning parts
  • Binder Jetting of a dual-phase steel: Process insight and optimisation using the Master Sintering Curve
  • The rise of filament-based metal AM: New materials and machines present opportunities for MIM producers
  • Sinter-based Additive Manufacturing at the 20th Plansee Seminar on Refractory Metals and Hard Materials
  • Ceramitec 2022: Opportunities abound for producers of technical ceramics by CIM and AM

The latest news from the MIM, CIM and sinter-based AM industries

Don't miss any new issue of PIM International, and stay up to date with the latest industry news. Sign up to our fortnightly newsletter.

Sign up

News from the industry…

    Discover our magazine archive…

    The free-to-access PIM International magazine archive offers unparalleled insight into the world of MIM, CIM and sinter-based AM from a commercial and technological perspective through:

    • Reports on visits to leading part manufacturers and industry suppliers
    • Articles on technology and application trends
    • Information on materials developments
    • Reviews of key technical presentations from the international conference circuit
    • International industry news

    All past issues are available to download as free PDFs or view in your browser.

     

    Browse the archive

     

    Looking for suppliers of materials, production equipment and finished MIM, CIM or sinter-based AM parts?

    Discover suppliers of these and more in our advertisers’ index and buyer’s guide, available in the back of PIM International.

    • Metal powders
    • MIM, CIM & AM parts producers
    • Binders & feedstocks
    • Feedstock mixers
    • Furnaces & furnace supplies
    • Atmospheres & gas generation
    • HIP systems & services
    • Injection moulding machines
    • AM technology
    • Debinding systems
    Download PDF
    Share via
    Copy link
    Powered by Social Snap