Effectiveness and cost-effectiveness of orthopaedic modifications to off-the-shelf footwear for people with first metatarsophalangeal joint osteoarthritis: study protocol for a randomised controlled trial

Introduction: Osteoarthritis (OA) is a chronic joint disease, often leading to pain, joint stiffness and impaired function. The first metatarsophalangeal (MTP-1) joint is the most frequently affected joint in foot OA. Footwear interventions might have potential to reduce pain for people with MTP-1 joint OA. The aim of this study is to determine the effectiveness and cost-effectiveness of orthopaedic modifications to off-the-shelf footwear in addition to usual care, compared to usual care alone, for people with MTP-1 joint OA. Methods and analyses: We perform a pragmatic, non-blinded, two-armed, parallel-group, randomised controlled trial (RCT). A total of 136 people with MTP-1 joint OA and presence of foot pain are recruited. Participants are randomised to orthopaedic modifications to off-the-shelf footwear in addition to usual care or to usual care alone. The footwear modifications comprise a combination of sole-stiffening, rocker sole adjustments and custom-made insoles. During a 12-month follow-up period, participants receive monthly questionnaires. Primary outcomes include walking pain at 6-month follow-up and quality-adjusted life years and societal costs at 12-month follow-up. Secondary outcomes include walking pain at 12-month follow-up and foot health, physical activity level, patient acceptability and self-reported recovery at 6- and 12-month follow-up. Intention-to-treat and per-protocol analyses will be performed using (generalised) linear mixed models. Ethics and dissemination: The study is approved by the local Medical Ethics Committee of the Erasmus MC University Medical Center Rotterdam, The Netherlands (MEC-2024-0615). Prior to study participation, participants provide informed consent. Results will be disseminated amongst researchers through peer-reviewed scientific articles and presentations at conferences; and amongst people with MTP-1 joint OA and healthcare professionals through layman articles in newsletters, on websites and on social media. Discussion: This is the first RCT to investigate the effectiveness and cost-effectiveness of orthopaedic modifications to off-the-shelf footwear in addition to usual care, compared to usual care alone for people with MTP-1 joint OA. Study findings will support healthcare professionals in making substantiated decisions in the treatment of people with MTP-1 joint OA.