Biomechanical and Wear Performance of a Total Ankle Replacement

Overview:

Ankle osteoarthritis is a relatively common condition involving wear and tear of the ankle joint and is associated with severe pain, impaired function and reduced quality of life. 65-80% of cases are post-traumatic, caused by sporting injuries and sprains. Ankle fusion is the most common end-stage treatment for ankle osteoarthritis, which involves fusing the three ankle joint bones together that limits the movement to reduce pain. Total ankle replacement (TAR) is an alternative to fusion, replacing the surfaces of the damaged joint with a motion preserving mechanical joint. However, TARs are associated with high surgical complexity and poor long-term survival rates (45% to 91% after 15 years) compared to fusion.

Mechanical joint simulators have successfully been used to mimic the load and range of motion produced by hip and knee replacements to determine their function and wear behaviour. There is still a lack of relevant pre-clinical testing to understand failure modes and wear behaviour, with current international standards using motion profiles from healthy ankle data and not from TAR patients. Therefore, the current project aims to understand how a TAR functions and wears under a range of clinically-relevant loading and range of motion conditions.

Motion capture software (gait analysis) will be used to identify key loading and range of motions of the ankle and lower body from fusion and TAR patients during a number of activities of daily living. The development of more clinically relevant mechanical wear simulations will improve the understanding of TAR function and wear. This will help guide surgical decision, improve international wear testing standards and increase the potential for successful and longer lasting future designs.   

Aims and Objectives:

1. To understand the function and wear of an ankle replacement under a number of loading and range of motion conditions.
2. To determine whether TAR provides better functional and patient reported outcomes than ankle fusion during a variety of activities of daily living.

Key Findings:

This work highlighted the influence of a variety of implant and simulator parameters on Total Ankle Replacement (TAR) wear simulation, alongside the improved biomechanical function of TAR when compared to Ankle Arthrodesis (AA). The study provided a useful benchmark for future TAR wear simulations, which should aim to develop a clinically relevant wear simulation protocol, under a variety of activities of daily living, to further understand the biomechanical and wear performance of a TAR.

Outputs:

J. Hopwood, A. Redmond, G. Chapman, L. Richards, S. Collins, C. Brockett. 2021. The Effect of Artificial Ageing on the Wear of a Total Ankle Arthroplasty. Orthopaedic Research Society, Virtual Meeting (12th-16th February 2021).

J. Hopwood, A. Redmond, G. Chapman, L. Richards, S. Collins, C. Brockett. 2020. A Comparison of Electromechanical versus Pneumatic-Controlled Knee Simulators for the Wear Performance of a Total Ankle Replacement. British Orthopaedic Research Society, Virtual Meeting (8th-9th September 2020).

J. Hopwood, A. Redmond, G. Chapman, L. Richards, S. Collins, C. Brockett. 2019. Influence of Implant Size on the Wear Performance of a Total Ankle Arthroplasty. International Society for Technology in Arthroplasty 32nd Annual Congress, Toronto, Canada (2nd-5th October 2019).

J. Hopwood, A. Redmond, G. Chapman, L. Richards, S. Collins, C. Brockett. 2018. The Biomechanical and Wear Performance of Total Ankle Replacements. Tissue and Cell Engineering Society, Keele, UK (2nd-4th July 2018).

Work Package	Early Disease and Risk Prediction: Prevent
Objective	3.1
Lead	James Hopwood
Investigators	Anthony Redmond, Graham Chapman, Laura Richards, Simon Collins and Claire Brockett
Institution	University of Leeds