Abstract:[Objective] To evaluate the clinical outcomes of high tibial osteotomy (HTO) combined with platelet-rich plasma (PRP) for medial knee osteoarthritis (MKOA) . [Methods] A retrospective study was conducted on 88 patients for MKOA in our hospital from Decem- ber 2016 to March 2020. According to doctor-patient communication results, patients were divided into 3 groups, 29 patients received HTO, 31 patients underwent PRP, while the remaining 28 patients were treated by HTO combined with PRP (the combined group) . The periopera- tive period, follow-up and imaging data were compared among the 3 groups. [Results] All the patients in the 3 groups had the corresponding procedures performed successfully without serious complications, and were followed up for more than 18 months. The combined group re- sumed full weight-bearing activity significantly earlier than the HTO group (P<0.05) . The VAS scores decreased significantly (P<0.05) , while the knee flexion and extension ROM and KOOS scores significantly increased in all the 3 groups over time (P<0.05) . Although there was no significant difference in the above items among the three groups before operation (P>0.05) , the combined group proved significantly superior to the other two groups at 6 months after operation (P<0.05) . At latest follow-up, the HTO group and the combined group proved sig- nificantly superior to the PRP group in terms of abovementioned scores (P<0.05) , while there were no significant differences in the scores be- tween the composite group and the HTO group (P>0.05) . Regarding imaging, the femorotibial angle (FTA) and medial proximal tibial angle (MPTA) were significantly improved in the HTO group and the combined group both immediately after surgery and at the last follow-up (P< 0.05) , but there was no significant change in Kellgren-Lawrence grade in the medial compartment (P>0.05) . At the corresponding time points, there was no significant difference in the above imaging indexes between the two groups (P>0.05) . [Conclusion] This HTO com- bined with PRP does significantly improve knee function and relieve pain, which is superior to any single therapy.