Innovate UK has provided funding for the research and clinical trials of a bio-active implant to treat post-operative infection following a total knee replacement (TKR).

It is expected to result a significant cost reduction incurred by the post-operative complications to the National Health Service (NHS), which is estimated to be £300m per year.

The programme is led by implant manufacturers MatOrtho and advanced metal coating developer the Wallwork Group.

Known as Smart Spacer, the new bio-active implant combines a bespoke TKR implant with surface coating, which responds to the physical and chemical stimulation triggered by use and implantation in the body.

Wallwork applies the physical vapour deposition (PVD) technique on its smart coating.

Its patented chromium-nitride silver coating (CrN-Ag) is fused directly to an existing cobalt-chromium TKR prosthesis.

It is usually placed after the removal of the primary TKR implant at the site of post-operative infection.

The device can facilitate faster stabilisation of the infection and is believed to reduce dependence on antibiotics.

It will be used as a temporary spacer device while treating periprosthetic infection.

The Smart Spacer directly treats infections such as MRSA and Staphylococcus Epidermis which are resistant to standard antibiotics.

The device involves two initial functions which are the release of silver ions from the CrN-Ag coating resulting to an active reduction of infection.

The coating also protects the cobalt-chromium TKR device, preventing the release of harmful metal ions into the patient.

Operating in two phases with movement and loading of the knee joint, the coating boosts silver ions from the sacrificial surface layer immediately after initial implantation to counter infection.

The device will then release lower levels of silver ions to maintain stability as recovery progresses.

"The programme is led by implant manufacturers MatOrtho and advanced metal coating developer the Wallwork Group."

The programme will be conducted over several key stages, the first being the simulated life testing of the coated knee joints by mechanical replication of normal movement enabling the Wallwork scientists optimises coating performance.

Completion of the first phase will be followed by a closely supervised clinical trial with patients.

The clinical trials are also being supported by the Royal National Orthopaedic Hospital, University College London and Queen Mary University London.

Image: The Smart Spacer. Photo: courtesy of Innovate UK/ ResponseSource Ltd. / Ainsworth Maguire.