https://www.selleckchem.com/products/dyngo-4a.html The 100% response rate confirmed ease of use. There were no redundant items. There were strong correlations between the 12-item and longer versions (>0.9). The HOOS-12 and KOOS-12 scores were reliable and valid 1) there were no ceiling or floor effects for pre- or postoperative KOOS-12 scores, although a ceiling effect was found for HOOS-12 postoperatively (20% of patients having maximum scores of 100); 2) internal consistency was confirmed, with Cronbach alpha>0.8; 3) external consistency between Oxford-12 and HOOS-12/KOOS-12 was excellent, with Pearson correlation coefficient>0.8. Sensitivity to pre-/postoperative change was confirmed, with effect size>0.8. The present study confirmed the usefulness of this new 12-item form for HOOS and KOOS. Properties were identical between the French- and English-language versions, authorising everyday use of these simpler versions. IV; prospective study without control group. IV; prospective study without control group. Preliminary evidence suggests that the COVID-19 pandemic has had a negative impact on children's mental health. Given these problems can have significant impacts throughout the lifespan, preventing the negative repercussions of COVID-19 on children's mental health is essential. Philosophy for children (P4C) and mindfulness-based interventions (MBIs) show promise in this regard. The goal of the present study was to compare the impact of online MBI and P4C interventions on mental health, within the context of the COVID-19 pandemic. We used a randomized cluster trial to assess and compare the impact of both interventions on elementary school students' (N=37) anxiety and inattention symptoms as well as on their basic psychological need satisfaction (BPN). ANCOVAs revealed a significant effect of the P4C intervention on mental health difficulties, controlling for baseline levels. Participants in the P4C group showed lower scores on the measured symptoms at post-test