Grip on Knee Osteoarthritis; DIstraction Versus Arthroplasty

Overview

The goal of this pragmatic, open, (1:1) randomized, multi-centre, non-inferiority trial is to to determine whether knee-joint distraction (KD) is non-inferior on patient reported effectiveness as compared to a knee-prosthesis (KP; i.e. usual care) for relatively young patients with end-stage knee Osteoarthritis (OA). The main question\[s\] it aims to answer are: * Is KD non-inferior to KP regarding pain, function and stiffness (as indicated by the total score on the total Western Ontario and McMaster Universities Osteoarthritis Index' (WOMAC), with a non-inferiority limit of 15 points) at 2 years? * Is KD non-inferior to KP regarding Quality of Life (36-Item Short Form Health Survey, (SF36), Physical- and Mental- Component Summary (PCS/MCS), with a non-inferiority limit of 10 points) at 2 years? * Does KD lead to regeneration of tissue (increase in minimum joint-space-width \> 0.05mm on x-ray) over 2 years? Participants will be allocated to undergo either a knee joint distraction or prosthesis (total- or unicompartmental KP according to orthopedic surgeon/patients discretion), and groups will be compared using will be compared between groups using (multivariable) random effects (mixed) modelling to account for the nested and longitudinal structure of the data over the 24 months follow-up. The stratification factors for randomization, center (using a random intercept) and gender, as well as a limited number of a priori defined prognostic factors (i.e. baseline WOMAC total score, age, BMI, severity of cartilage damage) will be accounted for in this analysis. The difference in mean total WOMAC score at 24 months between treatment groups will be estimated from this model with a 95% confidence interval (CI) and non-inferiority will be determined using the lower limit of this confidence interval.