https://www.selleckchem.com/products/avelestat-azd9668.html 71-0.93). In mode C, all measurements showed high to very high relative reliability (ICC 0.70-0.94) except upper extremity error rate and non-involved knee extension reaction time in PFPS group. The result of intra-session reliability showed that all measurements had high to very high relative reliability (ICC 0.78-0.94) in mode A. In mode B, all measurements showed high to very high relative reliability (0.78-0.94). The braking time seems more reliable than other reaction time tasks. In addition, the results showed that mode A is more reliable than other modes. The newly designed package is a reliable tool to measure the knee extension reaction time in patients with knee musculoskeletal disorders. The braking time seems more reliable than other reaction time tasks. In addition, the results showed that mode A is more reliable than other modes. The newly designed package is a reliable tool to measure the knee extension reaction time in patients with knee musculoskeletal disorders. Medical students and residents rely increasingly on web-based education. Online videos provide unique opportunities to share knowledge. The objective of this study was to investigate the accuracy and quality of instructional videos on the physical examination of the elbow and identify factors influencing educational usefulness. On October 7, 2018, a search on YouTube, VuMedi, Orthobullets, and G9MD was performed. Videos were rated for accuracy and quality by two independent authors using a modified version of a validated scoring system for the nervous and cardiopulmonary system. Inter-rater reliability was analysed. The 126 included videos were uploaded between June 2007 and February 2018. Twenty-three videos were indicated as useful for educational purposes. Accuracy, quality and overall scores were significantly higher for videos from specialized platforms (VuMedi, Orthobullets, G6MD) compared to YouTube. Video accuracy and quali