Multicentre randomised controlled trial protocol in China comparing postless hip arthroscopy with conventional perineal post-assisted hip arthroscopy to reduce perineal complications in patients undergoing hip arthroscopy for femoroacetabular impingement: the POSTLESS-HIP trial.

Introduction: Perineal complications-including nerve injury (eg, pudendal neurapraxia), soft tissue injury and sexual or urinary dysfunction-are well-documented adverse effects of conventional hip arthroscopy using a perineal post. Postless hip arthroscopy avoids direct perineal pressure, but high-quality randomised evidence is lacking.

Methods and analysis: This multicentre, prospective, parallel-group, randomised controlled trial will enrol 270 patients aged 15-60 years with femoroacetabular impingement syndrome requiring hip arthroscopy. Participants will be randomised 1:1 via a centralised system using stratified block randomisation by centre to postless hip arthroscopy or conventional perineal post-assisted traction. Sample size is calculated based on an assumed incidence of the primary composite endpoint (comprising perineal numbness, perineal pain, perineal soft tissue injury, sexual dysfunction and urinary dysfunction) of 10% vs 0.5%, yielding 114 per group (90% power, α=0.05); 135 per group accounts for 15% dropout. Surgeons cannot be blinded, but participants and outcome assessors are blinded. The primary outcome is the incidence of perineal nerve injury (perineal numbness, pain, soft tissue injury and sexual/urinary dysfunction) on postoperative day 1. Secondary outcomes include the incidence of perineal nerve injury at postoperative day 7 (discharge), non-perineal complications on postoperative day 1, preoperative preparation time, intraoperative traction time, total operative time, length of hospital stay censored at 6 weeks, patient-reported joint function outcomes assessed at 3 months using the Visual Analogue Scale (VAS), modified Harris Hip Score (mHHS), Hip Outcome Score and the International Hip Outcome Tool 12-item questionnaire, as well as a short-term economic evaluation consisting of 14-day postoperative VAS pain intensity, 14-day mHHS hip function and total direct healthcare costs within 14 days after surgery. Analyses will follow intention-to-treat principles.

Ethics and dissemination: Approved by the Chinese People's Liberation Army (PLA) General Hospital Ethics Review Board (No. 2024KY0158-KS001). Written informed consent will be obtained. Results will be published in peer-reviewed journals.

Trial registration number: NCT07322705.