Abstract: Objective To investigate the clinical effect of direct extra-articular endoscopic excision of popliteal cyst using double posteromedial portals.Methods For 92 patients in our department who suffered from symptoms such as pain and discomfort in the popliteal fossa,limited knee flexion,swelling after activity,and were diagnosed with popliteal cyst based on imaging examinations from March 2017 to January 2023,we performed direct extra-articular endoscopic excision of popliteal cyst using double posteromedial portals.The recurrence of cysts was evaluated by MRI at last follow-up.The Rauschning and Lindgren classification was used to evaluate clinical outcomes.Results A total of 92 patients were included in the study.Arthroscopic examination revealed intra-articular lesions in 80 patients (86.96%),including degenerative cartilage lesion in 52 patients (56.52%),medial meniscus tear in 48 patients (52.17%),lateral meniscus tear in 28 patients (30.43%),anterior cruciate ligament injury in 17 patients (18.48%),chondromalacia patellae in 3 patients (3.26%),intra-articular loose body in 2 patients (2.17%),tibial intercondylar eminence fracture in 1 patient (1.09%),gouty arthritis in 1 patient (1.09%),synovitis in 3 patients (3.26%) and septic arthritis in 1 patient (1.09%).The average duration of symptoms was 11.71 months (0.03 to 120 months).All patients were followed up postoperatively,with an average follow-up period of 12.8 months (6 to 23 months).There were no serious complications such as deep vein thrombosis,neurovascular injury or infection.Two patients were found to have residual cysts by MRI at last follow-up.According to the Rauschning and Lindgren classification:pre-operation:13 cases of grade Ⅰ,53 cases of grade Ⅱ and 26 cases of grade Ⅲ;post-operation:74 cases of grade 0 and 18 cases of grade Ⅰ.Conclusion Direct extra-articular endoscopic excision of popliteal cyst using double posteromedial portals has several advantages,such as mini-invasion,fast recovery,short surgical time and low recurrence rate.

Key words: arthroscopic；popliteal cyst；double posteromedial portals；extra-articular excision