A randomised controlled trial of the clinical and cost-effectiveness of ultrasound-guided intra-articular corticosteroid and local anaesthetic injections: the hip injection trial (HIT) protocol.

BACKGROUND: Evidence on the effectiveness of intra-articular corticosteroid injection for hip osteoarthritis is limited and conflicting. The primary objective of the Hip Injection Trial (HIT) is to compare pain intensity over 6 months, in people with hip OA between those receiving an ultrasound-guided intra-articular hip injection of corticosteroid with 1% lidocaine hydrochloride plus best current treatment with those receiving best current treatment alone. Secondary objectives are to determine specified comparative clinical and cost-effectiveness outcomes, and to explore, in a linked qualitative study, the lived experiences of patients with hip OA and experiences and impact of, ultrasound-guided intra-articular hip injection.

METHODS: The HIT trial is a pragmatic, three-parallel group, single-blind, superiority, randomised controlled trial in patients with painful hip OA with a linked qualitative study. The current protocol is described, in addition to details and rationale for amendments since trial registration. 204 patients with moderate-to-severe hip OA will be recruited. Participants are randomised on an equal basis (1:1:1 ratio) to one of three interventions: (1) best current treatment, (2) best current treatment plus ultrasound-guided intra-articular hip injection of corticosteroid (triamcinolone acetonide 40 mg) with 1% lidocaine hydrochloride, or (3) best current treatment plus an ultrasound-guided intra-articular hip injection of 1% lidocaine hydrochloride alone. The primary endpoint is patient-reported hip pain intensity across 2 weeks, 2 months, 4 months and 6 months post-randomisation. Recruitment is over 29 months with a 6-month follow-up period. To address the primary objective, the analysis will compare participants' 'average' follow-up pain NRS scores, based on a random effects linear repeated-measures model. Data on adverse events are collected and reported in accordance with national guidance and reviewed by external monitoring committees. Individual semi-structured interviews are being conducted with up to 30 trial participants across all three arms of the trial.

DISCUSSION: To ensure healthcare services improve outcomes for patients, we need to ensure there is a robust and appropriate evidence-base to support clinical decision making. The HIT trial will answer important questions regarding the clinical and cost-effectiveness of intra-articular corticosteroid injections.

TRIAL REGISTRATION: ISRCTN: 50550256 , 28th July 2015.