Arthroscopic Popliteal Cyst Excision: Technique and Outcomes with 2-Year Follow-Up

Purpose: This study describes an arthroscopic technique for popliteal cyst excision and report preliminary outcomes data. Methods: We retrospectively-identified patients with symptomatic popliteal cysts who underwent popliteal cyst excision at our institution between 2013 and 2020. Arthroscopic popliteal cyst excision was performed using dual posteromedial portals, expansion of the valvular mechanism, and cyst wall resection. International Knee Documentation Committee (IKDC) scores were collected pre-operatively and at follow-up. We calculated the proportions of patients meeting Patient Acceptable Symptomatic State (PASS) cutoffs for the IKDC, compared baseline and follow-up IKDC scores and the proportions of patients meeting PASS cutoffs, and examined the association between demographic and injury variables and outcomes. Results: Forty patients were eligible to be included in this study (mean age=52.1 years; mean follow-up time=3.7 years), and baseline IKDC data were available for 30 patients. The mean IKDC score at baseline was 42.6±14.9, compared to 70.4±22.4 at follow-up (p<0.01). At baseline, 13% of the cohort met the PASS cutoff for the IKDC. The proportion of the cohort meeting the IKDC PASS significantly increased at follow-up to 70% (p<0.01). Longer time post-surgery was associated with lower IKDC scores at follow-up (R2=12.7%; p=0.02) and with lower odds of meeting IKDC PASS at follow-up (OR=0.57; p=0.04). Higher pre-operative BMI was associated with lower IKDC scores at follow-up (R2=10.2%; p=0.04). No patients reported cyst recurrence nor need for surgical revision. Conclusions: This arthroscopic technique utilizing two posteromedial portals, expansion of the valvular mechanism, and cyst wall resection demonstrates good clinical outcomes at mean follow-up of 3.7 years in a cohort of 40 patients. Level of Evidence: IV (case series)