Abstract:[Objective] To compare the clinical outcomes of two anchor techniques in arthroscopic repair of the anterior talofibular liga- ment (ATFL) for chronic lateral ankle instability (CLAI). [Methods] A retrospective study was performed on 88 patients who underwent ar- throscopic repair of ATFL with anchors for CIAI in our hospital from January 2018 to January 2021. According to the doctor-patient com- munication preoperatively, 49 patients received repair with the knotless anchor, while the other 39 patients were with the knotted anchor. The perioperative, follow-up and imaging data of the two groups were compared. [Results] Although there were no significant differences in operation time, intraoperative blood loss, incision length, walking time and hospital stay between the two groups (P>0.05), the knotless group got significantly lower incidence of foreign body reaction than the knoted group (0% vs 33.3%, P<0.001). All patients were followed for more than 24 months, and there was no statistically significant difference in the time to regain full weight bearing between the two groups (P>0.05). Compared with those preoperatively, the ankle dorsal extension-plantar flexion range of motion (ROM), Karlson-Peterson score and AOFAS score significantly increased (P<0.05), while the varus-valgus ROM and VAS scores significantly reduced (P<0.05), and the anterior drawer test significantly improved in both groups at the latest follow-up (P<0.05). However, there were no statistically signifi- cant differences in the above indexes between the two groups at any time points accordingly (P>0.05). Regarding imaging, the talar tilt (TT) under inversion stress and anterior displacement (AD) under anterior drawer stress significantly reduced in both groups at the last followup compared with those preoperatively (P<0.05), whereas which were not statistically significant between the two groups at any time points accordingly (P>0.05). [Conclusion] Both kinds of anchor used in arthroscopic repair of ATFL for the CLAI do restore stability and achieve good clinical consequences. In contrast, the knotless anchor has less the early foreign body reaction than the knotted counterpart.