Metallic Materials for Artificial Hip Joints

Length: 2 weeks (introductory lecture, presentations, independent study)

Level: Year 2 Biomaterials/Bioengineering

Key skills: Group working, communication (presentation skills), independent study

Assessment: Group report and presentation and peer assessment



This is a group-based activity which looks at the metallic materials used in artificial hip joints.

Aims – to develop an appreciation of:

  • the types and the relative merits of the metallic materials used in the artificial hip joints.
  • factors influencing the choice of materials and component design for artificial hip joints.
  • how hip joint components are manufactured, and the importance of microstructural control.

Objectives – at the end of this case study students should be able to

  • establish the main design and property requirements for artificial hip protheses.
  • understand the microstructure and properties of 316L stainless steel, Co-Cr-Mo and Ti-6A14V alloys.
  • describe the processing routes (investment casting and forging) and their relative merits and pitfalls.
  • select surface engineering technologies to enhance fixation and combat wear.

Session 1

Briefing into the case study

Introductory lecture

Session 2

Work on task

Supervisor will be present to answer basic questions and check progress

Session 3

Group presentation

Finalise the reports, allowing for any information gained from the presentation.

Tasks

You will be expected to complete one of the following tasks (your supervisor will inform you of which task you are carrying out).

Task 1: Basic design and historical evolution

When to use an artificial hip joint (AHJ)

Main element of a AHJ

Different types of AHJs

Historical evolution of AHJs

Resources:

A. Eftekhar, N. S.  Principles of total hip arthroplasty

B. Sedel, L.  and Cabanela, M. E.  (eds.), Hip Surgery-Materials and Developments, Ch. 3/43

C. www.sulzerorthoeu.com/technology/tribology/metasu

D. http://www.midmedtec.co.uk

Task 2: Criteria for materials selection

Biocompatibilty

Mechanical properties

Surface properties

Resources:

A: Rubin, L. R.  Biomaterials in Restructive Surgery

B: Helsen, J. A. and Breme, H. J.  (eds), Metals as Biomaterials, Ch. 1

Task 3: Metallic alloys for AHJs

Titanium and titanium alloys

Austenitic stainless steels

Co-Cr alloys

Resources:

A: Ratner, B. D. et al. (eds), Biomaterials Science, Ch 1.

B: Dearnley, P. A.  Proc. Instn. Mech.Engrs. Vol. 213, Part H, pp. 107-135

C: Noort, R. V. (1987)  Journal of Materials Science, 22 , pp.3901-3811

Task 4: Processing routes

Forging and machining

Investment casting

PM/HIPping

Resources:

A: Helsen, J. A.  and Breme, H. J.  (eds), Metals as Biomaterials, Ch. 1.

B: Beeley, P. R. et al.(1995) (eds), Investment Casting, Section 12.4, Institute of Materials.

C: Luckey, H. A. and Kubli, F. (eds), Titanium Alloys in Surgical Implants, pp. 33 – 42.

Task 5: Fixation, surface engineering and British Standards

Assessment

Each group must submit a single written report addressing their task and summarising the main findings and conclusions drawn (60% of the case study mark). Each group must also give a 15 minute presentation (20% of the case study mark). You must allow 5 minutes at the end for questions. Ensure you introduce who you are and the main areas of your talk. Finish with a slide showing the main conclusions. Click for tips on presentations and reports.