Alex is Clinical Associate Professor in Orthopaedic Surgery at the MSK Lab, based at the Sir Michael Uren Hub on the White City Campus, and Consultant Orthopaedic Surgeon at St Mary's and Charing Cross Hospitals. His principal research interest is in the improvement of joint replacement surgery through the use of big data and new technologies. In particular, he is interested in technological approaches to the prevention and management of infection following joint replacement, and in the improvement of outcomes of partial knee replacement.

After studying medicine as an undergraduate at Imperial, Alex completed his basic and core surgical training in West London before joining the North West Thames Orthopaedic Higher Training Programme in 2010. Between 2011 and 2014 he undertook a DPhil (PhD) at the Univeristy of Oxford as an Arthritis Research UK / Royal College of Surgeons research fellow, under the supervision of Prof. David Murray, Prof. Hemant Pandit, Prof. Andy Judge and Prof. Richie Gill. His thesis, entitled "Failure of Unicompartmental Knee Replacement" was published in 2015 and resulted in a number of influential publications on the use of partial knee replacement.

Following his DPhil, Alex was appointed NIHR Clinical Lecturer at University College London, based at the Institute of Orthopaedics and Musculoskeletal Sciences at the Royal National Orthopaedic Hospital. Here he set up a study using advanced imaging technology better to understand the formation of biofilms on infected hip and knee replacements, in collaboration with Prof. Dave Spratt at the Eastman Dental Institute and funded by grants from Orthopaedic Research UK and the Royal College of Surgeons of England. Alongside this, in collboration with Mike Whitehouse at the University of Bristol, he conducted a study into the effect of implant materials on the rate of infection following knee replacement, using data from the National Joint Registry for England and Wales.

At Imperial, he has conducted large-scale projects on the outcomes of joint replacements in the hip, knee, and shoulder, and continued his work on prosthetic joint infection in conjuction with his clinical work at the West London Major Revision Centre. In collaboration with the department of Mechannical Engineering at Imperial, he has worked on novel bone-facing surfaces for joint replacement, work which has produced a novel unicompartmental knee replacement prosthesis which has been spun out into a start up company which has raised £4.5 million in grant and investment capital and is on track for first in human use in 2026. 

Alex is Surgical Speciality Lead for Elective Orthopaedic Surgery at the Royal College of Surgeons, sits on the Research Committee of the British Orthopaedic Association and the Editorial Board of the Bone and Joint Journal. He sits on the Surgical Trials Committee at Imperial College. He consults for Zimmer Biomet, JRI and AllogenRx and is Chief Medical Officer of Osstec. In his clinical work, Alex specialises in joint replacement in the hip and knee, including partial, primary and revision knee replacement, hip resurfacing, primary and revision hip replacement. He also works at the Major Trauma Centre at St Mary's Hospital, specialising in complex periarticular and periprosthetic fractures in the hip and knee.

Selected Publications
A full list is available under the 'publications' tab

Liddle AD, Judge A, Pandit H, Murray DW. Adverse outcomes after Total and Unicompartmental Knee Replacement: a study of 101,330 matched patients from the National Joint Registry for England and Wales. Lancet 2014;384(9952):1437-45.

Liddle AD, Pandit H, Judge A, Murray DW. The effect of surgical caseload on revision rate following total and unicompartmental knee replacement. J Bone Joint Surg (Am) 2016;98(1):1-8.

Liddle AD, Judge A, Pandit H, Murray DW. Determinants of revision and functional outcome following unicompartmental knee replacement. Osteoarthritis and Cartilage 2014;22(9):1241-50.

Hexter AT, Hislop SM, Blunn GW, Liddle AD. The effect of bearing surface on risk of prosthetic joint infection in total hip arthroplasty: a systematic review and meta-analysis. Bone Joint J 2018;100(2):134-142

Burn E, Liddle AD, Hamilton TW, Judge A, Pandit HG, Murray DW, Pinedo-Villanueva R. Cost-effectiveness of unicompartmental compared to total knee replacement: a population-based study using data from the National Joint Registry for England and Wales. BMJ Open 2018;8(4): e020977.

Teaching
Alex is active in teaching both undergraduate and postgraduate students. He is Assessment Lead for Year 3 of the MBBS course and chairs the Phase 1c Exam Board.. He supervises PhD and MPhil students, is an educational supervisor for surgeons in training, and teaches on internal and external courses for postgraduate surgical trainees.