[Therapeutic effects of internal drainage by expanding arthroscopic gastrocnemius-semimembranosus bursa and cyst wall resection for the treatment of 41 patients with popliteal cysts].

OBJECTIVE: To investigate the clinical curative effects of internal drainage by expanding arthroscopic gastrocnemius-semimembranosus bursa(GSB) and cyst wall resection for the treatment of popliteal cysts. METHODS: A retrospective analysis of patients from May 2011 to December 2015. Arthroscopic treatment for 41 patients with popliteal fossa cysts, 18 males and 23 females, aged from 34 to 67 years old, averaged 42.6 years old. All the patients had preoperative magnetic resonance imagings to confirm the diagnosis and identify the valvular opening(Gastrocnemius-Semimembranosus bursa, GSB), as well as the associated intra-articular pathology. All the popliteal cysts were unilateral, including 26 cases of right knees and 15 cases of left knees. Five patients had recurrent popliteal cysts, and all of them underwent initial open Surgery. The duration from initial surgery to the recurrence ranged from 6 to 17 months(averaged, 11 months). All the patients had underwent arthroscopic treatment of internal drainage by expanding GSB and cyst wall resection. According to the Rauschning and Lindgren classification, 5 cases were grade I , 30 cases were grade II and 6 cases were grade III. Preoperative Lysholm score, 83.19±6.12 (ranged form 73 to 95). RESULTS: The GSB structure was found in all patients with popliteal cysts during operation, including cartilage degeneration in 33 cases, medial meniscus injury in 27 cases, lateral meniscus injury in 7 cases, free body in 8 cases, pigmented villonodular synovitis in 2 cases, and synovial chondromatosis in 3 cases. There were no complications related to vascular, nerve or surgical incision. All the patients were followed up, and the duration ranged from 8 to 27 months, with an average of 18 months. No recurrence of cysts was found. According to the Rauschning and Lindgren classification, there were 9 cases of grade 0, 27 cases of grade I , 4 cases of grade II, 1 case of grade III. Postoperative Lysholm score:91.32±4.26(ranged from 82 to 98). CONCLUSIONS: Arthroscopic internal drainage by expanding GSB and cyst wall resection surgery in the treatment of popliteal cysts has the advantages of less trauma, faster recovery and low relapse rate, which has a good short-term effect.