OBJECTIVE: Evaluation of the clinical effectiveness and safety of a new custom-made valgus knee brace (OdrA) in medial knee osteoarthritis (OA) in terms of pain and secondary symptoms. METHODS: Open-label prospective study of patients with symptomatic medial knee OA with clinical evaluation at 6 and 52 weeks (W6, W52). We systematically assessed pain on a visual analog scale (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), spatio-temporal gait variables, use of nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesic-sparing effects of the brace and tolerance. Mean scores were compared at baseline, W6 and W52 and the effect size (ES) and 95% confidence intervals (95% CIs) were calculated. RESULTS: We included 20 patients with knee OA (mean age 64.2+/-10.2 years, mean body mass index 27.2+/-5.4 kg/m2). VAS pain and KOOS were improved at W6 and W52: pain (ES=0.9 at 1 year), amelioration of other symptoms (ES=0.4), and function in activities of daily living (ES=1.1), sports and leisure (ES=1.5), quality of life (ES=0.9) and gait speed (ES=0.41). In total, 76% of patients showed clinical improvement at 1 year. Analgesic and NSAIDs consumption was significantly decreased at W6 and W52. One serious adverse effect noted was lower-limb varices, and observance was deemed satisfactory at 1 year. CONCLUSION: This new unloader brace appeared to have good effect on medial knee OA, with an acceptable safety profile and good patient compliance.