Author contribution: Lychagin AV devised a KJDS scale, planned the study, performed arthroscopy and follow-up observation, processed and analyzed the data. Garkavi AV planned the study and proposed its design, performed arthroscopy, intraarticular injections and follow-up observation, processed and analyzed the data, and wrote the manuscript. Meshcheryakov VA performed arthroscopy, intraarticular injections and follow-up observation, surveyed the patients. Kaykov VS performed arthroscopy, intraarticular injections, and follow-up observation, surveyed the patients.