Abstract:[Objective] To investigate clinical efficacy of high tibial osteotomy (HTO) combined with arthroscopic debridement (AD)and platelet-rich plasma (PRP) intraarticular injection for medial knee osteoarthritis (mKOA). [Methods] A retrospective study was conduct-ed on 33 patients who received HTO for mKOA in our hospital from November 2015 to July 2019. According to doctor-patient communica-tion, 17 patients received HTO+AD+PRP treatment (combination group), and the other 16 patients received HTO treatment only. The periop-erative, follow-up and imaging data of the two groups were compared. [Results] All patients in both groups were operated on smoothly, with-out significant differences in operation time, total incision length, intraoperative blood loss, incision healing grade, ambulation time and hos-pital stay between the two groups (P>0.05). All patients were followed up for more than 30 months, and the combined group resumed fullweight-bearing activities significantly earlier than the HTO group [(58.1±4.6) days vs (66.1±4.0) days, P<0.05]. The VAS and WOMACscores decreased significantly (P<0.05), while Lysholm and HSS scores significantly increased over time in both groups (P<0.05). Althoughthere was no significant differences in abovesaid scores between the two groups before operation (P>0.05), the combined group proved signifi-cantly superior to the HTO group in terms of VAS [(2.4±0.5) vs (2.8 ±0.5), P<0.05], WOMAC [(18.4± 2.0) vs (23.7±2.5), P<0.05], HSS [(80.8±3.0) vs (73.3±2.5), P<0.05] and Lysholm score [(79.1±3.6) vs (71.4±2.8), P<0.05] at the latest follow-up. Regarding imaging, the medial prox-imal tibial angle (MPTA) and femorotibial angle (FTA) significantly improved (P<0.05), whereas the K-L classification remained unchangedin both groups at 6 months and 1 year after surgery compared with those preoperatively (P>0.05). However, there were no statistically signifi-cant differences in the above imaging items between the two groups at any time points accordingly (P>0.05). [Conclusion] HTO combinedwith arthroscopic debridement and PRP does significantly improve knee joint function, relieve pain and improve patient satisfaction, andachieves clinical efficacy better than that of HTO only.