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. 2025 Feb 10;6(2):164-177.
doi: 10.1302/2633-1462.62.BJO-2024-0155.R1.

Total versus robotic-assisted unicompartmental knee replacement (TRAKER) for medial compartment osteorthritis: a randomized controlled trial

Nick D Clement  1 ; TRAKER Research Group; Chloe E H Scott  1   2 , Gavin J Macpherson  1 , Philip M Simpson  1 , Gillian Leitch  1 , James T Patton  1 , Issaq Ahmed, Anish K Amin, Paul Gaston, Ewan Goudie, Stuart Goudie, Deborah M Macdonald, Eliott Martinson, Matthew Moran, Fazer Wade
Affiliations

Total versus robotic-assisted unicompartmental knee replacement (TRAKER) for medial compartment osteorthritis: a randomized controlled trial

Nick D Clement et al. Bone Jt Open. .

Abstract

Aims: Unicompartmental knee arthroplasty (UKA) is associated with an accelerated recovery, improved functional outcomes, and retention of anatomical knee kinematics when compared to manual total knee arthroplasty (mTKA). UKA is not universally employed by all surgeons as there is a higher revision risk when compared to mTKA. Robotic arm-assisted (ra) UKA enables the surgeon to position the prosthesis more accurately when compared to manual UKA, and is associated with improved functional outcomes and a lower early revision risk. Non-randomized data suggests that, when compared to mTKA, raUKA has a clinically meaningful greater functional benefit. This protocol describes a randomized controlled trial that aims to evaluate the clinical and cost-effectiveness of raUKA compared to mTKA for individuals with isolated medial compartment osteoarthritis (OA).

Methods: The total versus robotic-assisted unicompartmental knee arthroplasty (TRAKER) trial is a patient- and assessor-blinded, pragmatic parallel two-arm randomized superiority trial of adults undergoing elective primary knee arthroplasty for primary medial compartment OA at a single NHS hospital (ClinicalTrials.gov NCT05290818). Participants will be randomly allocated on a 1:2 basis to either raUKA or mTKA, respectively. The primary analysis will compare the Oxford Knee Score (OKS) six months after surgery. Secondary outcomes measured at three, six, and 12 months include the OKS, Forgotten Joint Score, patient expectations, EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (EQ-VAS), patient satisfaction, range of motion, postoperative complications, need for further surgery, resource use, and financial costs. Cost-effectiveness will be measured over a ten-year time span. A total of 159 patients will be randomized (n = 53 raUKA vs n = 106 mTKA) to obtain 80% power to detect a five-point difference in OKS between the groups six months after surgery.

Conclusion: The trial findings will provide evidence about the clinical and cost-effectiveness of raUKA compared to mTKA in patients with isolated medial compartment OA. This will inform future National Institute for Health and Care Excellence guidelines on primary knee arthroplasty in the UK.

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Conflict of interest statement

C. E. H. Scott reports an institutional grant and payment for teaching on courses from Stryker; consulting fees from Stryker, Smith & Nephew, and Osstec; participation on the advisory board for Osstec and Smith & Nephew, and participation on the data safety monitoring for the PASHION study; and being the Editor-in-Chief for Bone & Joint Research and on the editorial board for The Bone & Joint Journal, all of which are unrelated to this manuscript. N. D. Clement is also on the editorial board for The Bone & Joint Journal and Bone & Joint Research, which are unrelated. G. J. Macpherson discloses a consultant contract, and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Stryker, which are unrelated to this work. J. Patton also receives unrelated payments for lectures and teaching from Stryker, and is a board member for The Bone & Joint Journal. P. Simpson also reports payments for the development of a robotic-assisted knee arthroplasty and educational courses from Stryker, which are also unrelated.

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