Researching the use of ceramic implants

Of the three types of shoulder replacement procedure, the hemiarthroplasty, a partial replacement involving the removal of the top section of the humerus, has fallen out of fashion.  This is despite the obvious advantage of this procedure being that surgeons only need to replace one side of the joint, leaving sufficient bone stem to allow further treatment should the patient’s condition deteriorate.  Unfortunately, the procedure has tended to result in a high revision rate, which is why many clinicians have preferred more invasive procedures, involving the replacement of the whole joint. These procedures are effective, especially in reducing pain, but are difficult to revise should something go wrong in the future, which is a particular concern when treating with younger patients.

This research project by a team led by Imperial College London’s Biomechanics Group is aiming to test the use of a ceramic implant in the hemiarthroplasty procedure to establish whether this material can deliver lower revision rates. The technique has been championed by consultant orthopaedic surgeon, Mr Peter Riley, who has observed that his patients experienced lower levels of bone and cartilage wear when he uses a ceramic rather than a metal implant.  The researchers have undertaken material tests to measure the relative effectiveness of ceramic and metal implants, but the new project involves the use of a shoulder simulator to provide a biomechanical test of how the materials perform.  Should this test prove successful, the data generated will be used to make a case for clinical studies into the effectiveness of the ceramic material.

Dr Ulrich Hansen, Senior Lecturer in the Medical Engineering Group within the Mechanical Engineering Department at Imperial, who is leading the project, explains how the ultimate aim is to provide evidence to support Peter Riley’s observations and change clinician’s perceptions of the effectiveness of the hemiarthroplasty procedure:

Surgeons are sceptical about the ‘hemi’ because of the apparent high revision rates, so much so that what was once the most common procedure is now only used in a small number of cases. If we can provide the clinical data to reassure clinicians, we can help to transform thinking in this area.

ORUK’s funding has been essential in helping us reach this stage. Investors and manufacturers will always be guided by the opinions of clinicians which, given their current negative perceptions of the hemi, means that we would have struggled for research funding without ORUK’s involvement. If this initial research proves successful, Peter Riley and I believe that it has the potential to unlock additional research funding and innovation from manufacturers into the use of ceramic implants.