NCT07385560

"The Importance of Adding Fenestration to Ultrasound-Guided Baker's Cyst Aspiration"

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (estimated)
• Sponsor: Istanbul University - Cerrahpasa · Academic / Other
• Sex: All
• Age: 40 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

This study aims to evaluate whether adding a fenestration procedure to standard ultrasound-guided aspiration and corticosteroid-lidocaine injection provides additional clinical benefits for patients with symptomatic Baker's cyst associated with knee osteoarthritis. Baker's cyst is a fluid-filled swelling located behind the knee that may cause pain, stiffness, swelling, and limited mobility. Although aspiration with medication injection is commonly used to relieve symptoms, recurrence of the cyst is frequent. Fenestration is a minimally invasive technique in which small controlled openings are created in the cyst wall under ultrasound guidance to improve internal drainage and potentially reduce recurrence. In this prospective, randomized, double-blind, controlled study, participants will be assigned to one of two groups: 1. aspiration with corticosteroid and lidocaine injection, or 2. aspiration with corticosteroid and lidocaine injection plus fenestration. Pain, functional scores, cyst measurements, and recurrence will be assessed at follow-up visits at 2 weeks, 1 month, and 3 months. The purpose of this study is to determine whether the addition of fenestration results in better symptom improvement and lower rates of recurrence compared with standard aspiration alone.

Detailed description

Baker's cyst, also known as a popliteal cyst, is frequently observed in patients with knee osteoarthritis and is typically associated with intra-articular pathology that increases synovial fluid production. Ultrasound-guided aspiration combined with corticosteroid-lidocaine injection is a widely used minimally invasive treatment; however, recurrence remains a significant limitation of this method. Fenestration involves creating multiple small perforations in the cyst wall using a needle under real-time ultrasound guidance. This technique is expected to enhance communication between the cyst and surrounding tissues, promote better fluid redistribution, and reduce the likelihood of reaccumulation. This prospective, randomized, double-blind, controlled clinical trial will enroll adult patients meeting the 2010 ACR criteria for knee osteoarthritis and demonstrating a symptomatic Baker's cyst on ultrasound. Participants will be randomized in a 1:1 ratio into two groups: Group 1: aspiration + corticosteroid-lidocaine injection Group 2: aspiration + corticosteroid-lidocaine injection + fenestration All procedures will be performed by a trained physiatrist using sterile technique and real-time ultrasonography. Outcome measures include VAS pain scores, KOOS, WOMAC, Rauschning-Lindgren classification, ultrasonographic cyst dimensions, and aspirated fluid volume. Assessments will be conducted at baseline and at 2-week, 1-month, and 3-month follow-up visits. The primary objective is to investigate whether fenestration, when added to aspiration, enhances clinical outcomes and reduces recurrence rates. Secondary objectives include evaluating functional improvements, changes in cyst size, and patient-reported symptoms. The study duration for each participant is 3 months, and the overall study is planned to be completed within 5 months.

Conditions

• Baker Cyst
• Fenestration
• Musculoskeletal Ultrasound
• Steroid Injection
• OMERACT
• Knee Osteoarthritis

Interventions

Type	Name	Description
PROCEDURE	Baker's Cyst Aspiration	With the patient in the prone position, the ultrasound probe is placed transversely over the gastrocnemius-semimembranosus bursa. Under real-time ultrasound guidance, the needle is advanced while visualizing neurovascular structures to avoid injury. Aspiration of the cyst content is performed in all participants.
DRUG	Steroid-Lidocaine Injection	Following aspiration, an injection mixture consisting of 1 mL betamethasone, 1 mL of 2% lidocaine, and 1 mL of 0.9% isotonic sodium chloride is administered into the decompressed cyst cavity under ultrasound guidance.
PROCEDURE	Ultrasound-Guided Fenestration	After aspiration, fenestration of the cyst wall is performed under ultrasound guidance. The cyst wall is punctured at a minimum of six different points using a needle to create communication with surrounding tissues and reduce recurrence. Following fenestration, the same steroid and local anesthetic mixture is administered.

Timeline

• Start date: 2026-02-15
• Primary completion: 2026-05-30
• Completion: 2026-05-30
• First posted: 2026-02-04
• Last updated: 2026-02-04

Locations

1 site across 1 country: Turkey (Türkiye)