Aim Vagus nerve stimulation has emerged as a plausible intervention to reduce ileus after surgery. An early development study was undertaken with the aim of exploring the feasibility of self‐administered, noninvasive vagus nerve stimulation (nVNS) after major colorectal surgery. Method A parallel‐group, randomized controlled trial was undertaken between 1 January 2018 and 31 August 2019. Forty patients undergoing colorectal surgery for malignancy were allocated equally to Sham and Active stimulation groups. Electrical vagus nerve stimulation was self‐administered bilaterally over the cervical surface landmarks for 5 days before and after surgery. Outcomes of interest were postoperative complications and adverse events measured using the Clavien–Dindo scale, treatment compliance, device usability according to the Systems Usability Scale (SUS) and clinical measures of bowel recovery. Results Forty patients were randomized and one withdrew, leaving 39 for analysis. Postoperative complications occurred in 9/19 (47.4%) participants receiving Sham and 11/20 (55.0%) receiving Active stimulation and were mostly minor. Compliance with treatment before surgery was 4.7 ± 0.9 days out of 5 days in the Sham group and 4.7 ± 1.1 in the Active group. Compliance with treatment after surgery was 4.1 ± 1.1 and 4.4 ± 1.5, respectively. Participants considered the intervention to be ‘acceptable’ according to the SUS. The most prominent differences in bowel recovery were days to first flatus (2.35 ± 1.32 vs 1.65 ± 0.88) and tolerance of solid diet (2.18 ± 2.21 vs 1.75 ± 0.91) for Sham and Active groups, respectively. Conclusion This study supports the safety, treatment compliance and usability of self‐administered nVNS in patients undergoing major colorectal surgery.

Introduction Knee replacement (KR) is a clinically proven procedure typically offered to patients with severe knee osteoarthritis (OA) to relieve pain and improve quality of life. However, artificial joints fail over time, requiring revision associated with higher mortality and inferior outcomes. With more young people presenting with knee OA and increasing life expectancy, there is an unmet need to postpone time to first KR. Knee joint distraction (KJD), the practice of using external fixators to open up knee joint space, is proposed as potentially effective to preserve the joint following initial studies in the Netherlands, however, has not been researched within an NHS setting. The KARDS trial will investigate whether KJD is non-inferior to KR in terms of patient-reported postoperative pain 12 months post-surgery. Methods and analysis KARDS is a phase III, multicentre, pragmatic, open-label, individually randomised controlled non-inferiority trial comparing KJD with KR in patients with severe knee OA, employing a hybrid-expertise design, with internal pilot phase and process evaluation. 344 participants will be randomised (1:1) to KJD or KR. The primary outcome measure is the Knee Injury and Osteoarthritis Outcomes Score (KOOS) pain domain score at 12 months post-operation. Secondary outcome measures include patient-reported overall KOOS, Pain Visual Analogue Scale and Oxford Knee Scores, knee function assessments, joint space width, complications and further interventions over 24 months post-operation. Per patient cost difference between KR and KJD and cost per quality-adjusted life year (QALY) gained over 24 months will be estimated within trial, and incremental cost per QALY gained over 20 years by KJD relative to KR predicted using decision analytic modelling. Ethics and dissemination Ethics approval was obtained from the Research Ethics Committee (REC) and Health Research Authority (HRA). Trial results will be disseminated at clinical conferences, through relevant patient groups and published in peer-reviewed journals. Trial registration number NCT14879004;recruitment opened April 2021.