Bone Cement and its Pressurisation within the Acetabulum during Total Hip Arthroplasty

Lead Research Organisation: Newcastle University
Department Name: Sch of Engineering

Abstract

Aim
To further the understanding of bone cement behaviour and the relationship between pressure, cement penetration and longevity of implant when different pressurisers are used, and use this knowledge to compare efficacy of existing designs of acetabular cement pressurisers. This will increase understanding and highlight the properties which govern longevity of the acetabular cup in a total hip arthroplasty, improving patient satisfaction and reducing the cost spent by the NHS on revision surgery.

Background
As the population ages the bill that the NHS must pay for joint replacements continues to rise, and efforts to improve the longevity of implants is crucial for both the NHS and for patients receiving them. This project will focus on total hip replacements (THR). There are three fixation methods: uncemented, cemented and hybrid; the first two are self-explanatory, hybrid fixation meaning the femoral component is cemented and the acetabular cup is fixed using uncemented means. The hybrid fixation method is currently the most cost effective while cemented is the cheapest; the uncemented method performs worst in terms of cost. Despite this, according to National Joint Registry (NJR) data, the hybrid method of fixation is the least popular as of 2016 but is increasing in popularity, cemented is only just more common with decreasing popularity, and uncemented is the most popular but is also decreasing in popularity. According to other NJR data regarding cumulative percentage probability that an implant will need revision some years after implantation, hybrid and cemented implants perform similarly in terms of likelihood of revision over 13 years while uncemented implants are far more likely to need revision at any point after surgery. All this data suggests that if the longevity of total hip replacements implanted using cemented fixation methods is slightly improved it would be the most cost effective method.

The primary location of failure of cemented total hip replacements is at the bone cement-bone interface on the side of the acetabular component; therefore, studying this interface with the aim of improving its longevity shall be the focus of this project.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509528/1 01/10/2016 30/09/2021
1953073 Studentship EP/N509528/1 01/10/2017 30/09/2021 Alexander Boote
 
Description Whilst PMMA Bone Cement is setting a equilibrium modulus appears and increases. The development of an equilibrium modulus means that deformations that are applied to the cement that are not allowed to recover will result in a residual stress. This can weaken the cement and significantly reduce its longevity.
Exploitation Route Development and further testing of new designs of surgical instruments to minimise deformation.
Sectors Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology