Objective:To explore the mechanism of extracorporeal shock wave combined with platelet rich plasma in the treatment of articular cartilage injury in knee osteoarthritis (KOA) rats based on the silent information regulator 1 (Sirt1)/forkhead transcription factor O1 (FoxO1) pathway.Methods:15 SD rats were used for platelet rich plasma extraction and 35 SD rats were randomly divided into blank control group, model group, extracorporeal shock wave group, platelet rich plasma group, and extracorporeal shock wave + platelet rich plasma group. Each group had 7 cases. After the intervention, HE staining of articular cartilage tissue was used to observe changes in articular cartilage morphology, Mankin score was used for pathological evaluation, CCK-8 method was used to detect chondrocyte vitality and proliferation, ELISA method was used to detect inflammatory factor levels in joint fluid, and Western Blot method was used to detect the expression levels of Sirt1 and acely-FoxO1/FoxO1 in five groups of articular cartilage tissue.Results:The HE staining of articular cartilage tissue showed that model group, extracorporeal shock wave group, platelet rich plasma group, and extracorporeal shock wave + platelet rich plasma group had varying degrees of pathological damage, with model group having the most severe pathological damage, while the other three experimental groups had no significant differences. The Mankin score and the level of acely-FoxO1/FoxO1 in articular cartilage tissue showed that blank control group < extracorporeal shock wave + platelet rich plasma group < platelet rich plasma group < extracorporeal shock wave group < model group (all P < 0.05). The results of Sirt1 level in articular cartilage tissue, activity, and proliferation ability of articular chondrocytes showed that model group < extracorporeal shock wave group < platelet rich plasma group < extracorporeal shock wave + platelet rich plasma group < blank control group (all P < 0.05). Comparison of inflammatory factor levels in joint fluid, blank control group < extracorporeal shock wave + platelet rich plasma group < extracorporeal shock wave group < platelet rich plasma group < model group (all P < 0.05). Conclusions:The combination of extracorporeal shock wave and platelet rich plasma can promote the proliferation of osteoarthritis chondrocytes and alleviate joint inflammation and cartilage damage in KOA rats by upregulating Sirt1 expression and downregulating FoxO1 acetylation levels.