Abstract:[Objective] To investigate the clinical efficacy and safety of arthroscopic debridement and microfracture combined withplatelet-rich plasma (PRP) for post-traumatic osteoarthritis (PTOA) of the ankle. [Methods] A retrospective study was done on 41 patientswho received surgical treatment for PTOA from February 2019 to February 2021. According to doctor-patient communication, 23 patients re-ceived PRP injection intraarticularly following the arthroscopic procedure, while the remaining 18 patients had hyaluronic acid (HA) inject-ed intraarticularly after surgery. The document regarding perioperative period, follow-up and auxiliary examination were compared betweenthe two groups. [Results] There were no significant differences in operation time, intraoperative blood loss, total incision length, incisionhealing grade, deep venous thrombosis of lower limbs and hospital stay between the two groups (P>0.05). All patients in both groups were fol-lowed up for more than 12 months, without a significant difference in the time to resume full weight-bearing activity between the two groups(P>0.05). The VAS and AOFAS scores improved significantly (P<0.05), while the ankle dorsal-plantar flexion range of motion (ROM) re-mained unchanged over time in both groups (P>0.05). At 12 months after surgery, the PRP group proved significantly superior to the HAgroup in terms of VAS score [(1.3±0.6) vs (2.7±1.1), P<0.05] and AOFAS score [(80.9±6.5) vs (71.0±5.6), P<0.05]. Regarding laboratory test-ing, the Hs-CRP, IL-6 and TNF-α significantly decreased in both groups over time (P<0.05). The PRP group was significantly better thanthe HA group in terms of Hs-CRP [(3.1±0.3) mg/L vs (6.7± 0.1) mg/L, P<0.05], IL-6 [(3.0±0.3) ng/L vs (4.0±0.3) ng/L, P<0.05] and TNF-α[(4.2±0.6) ng/L vs (5.2±0.6) ng/L, P<0.05] 12 months postoperatively. Radiographically, there were no significant changes in TT and mLDTAin both groups 6 and 12 months postoperatively compared with those preoperatively (P>0.05). However, the Kellgren-Lawrence (K-L) classi-fication for osteoarthritis in the PRP group significantly improved 12 months after surgery (P<0.05), which in the HA group remained not sig-nificantly changed (P>0.05). At 12 months after surgery, the PRP group proved significantly superior to the HA group in K-L stage [I/II/IIIa/IIIb/IV, (0/16/6/1/0) vs (0/7/7/4/0), P<0.05]. [Conclusion] Arthroscopic debridement and microfracture combined with PRP does signifi-cantly improve the clinical efficacy for post-traumatic osteoarthritis of the ankle with high safety.