Arthroscopic Internal Drainage And Arthroscopic Internal Drainage Combined With Cyst Wall Excision To Treat Unicameral Popliteal Cysts: A Retrospective Case-control Study

Objective:To compare the clinical efficacy and safety of arthroscopic internal drainage and arthroscopic internal drainage combined with cyst wall excision for the treatment of unicameral popliteal cysts.Methods:This was a retrospective case-control study of 73 patients diagnosed with unicameral popliteal cysts from January 2012 to January 2019 who received arthroscopic treatment.The study included 38 cases with internal drainage combined with cyst wall excision(experimental group)and 35 cases with internal drainage(control group).The experimental group consisted of 14 men and 24 women with an average age of 51.8 years,while the control group consisted of 13 men and 22 women with an average age of 52.0 years.All patients were examined for intra-articular lesions and communicating ports by magnetic resonance imaging(MRI)prior to surgery,and recurrence of cysts was evaluated at the last follow-up examination.Rauschning and Lindgren grade and Lysholm score were used to evaluate clinical outcomes.In addition,operation time and complications were recorded.Results:The average length of follow-up was 24.2 months(range 16 to 32 months).There were no considerable differences in age,gender,cyst size,Lysholm score,R-L grade and concomitant intra-articular cases between two groups prior to surgery(P>0.05).The last follow-up MRI scans showed that in the experimental group,the cyst disappeared in 25 cases and shrunk in 13 cases.In the control group,the cyst disappeared in 22 cases,shrunk in 12 cases and persisted in 1 case.There was no obvious difference in recurrence rate between the two groups(0% vs 2.9%,P =0.899).At the last follow-up,there were no differences in the Rauschning and Lindgren grade(P=0.630)and Lysholm score(88.3±5.6 points vs 90.1±3.8 points,P=0.071)between the two groups.Compared with the control group,operation time was significantly prolonged in the experimental group(38.3±3.1min vs 58.3±4.4min,P < 0.05).In the experimental group,six cases occurred fluid infiltration under the gastrocnemius muscle,which improved after pressure bandaging and cold compress.The incidence of complications in the experimental group was markedly higher than that in the control group(15.8% vs 0%,P < 0.05).During the follow-up period,none of the patients developed serious complications such as neurovascular injury,deep venous thrombosis or infection.Conclusion:For unicameral popliteal cysts,arthroscopic internal drainage combined with resection of the cyst wall did not further improve the clinical outcomes or reduce the recurrence rate,while prolonging the operation time and increasing the possibility of complications.