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

Istanbul University - Cerrahpasa

Status: Begins enrollment this month

Conditions: OMERACT; Fenestration; Musculoskeletal Ultrasound; Baker Cyst; Steroid Injection; Knee Osteoarthritis

Treatments: Procedure: Baker's Cyst Aspiration; Procedure: Ultrasound-Guided Fenestration; Drug: Steroid-Lidocaine Injection

Study type: Interventional

Funder types: Other

Identifiers

NCT07385560

E-24687290-604.01-1407310 (Other Identifier)

Details and patient eligibility

About

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.

Full 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.

Enrollment: 44 estimated patients

Sex: All

Ages: 40 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adults aged 40 to 75 years
• Diagnosis of knee osteoarthritis according to the 2010 American College of Rheumatology (ACR) criteria
• Presence of a symptomatic Baker's cyst confirmed by ultrasonography
• Ability to understand study procedures and provide written informed consent
• Sufficient intellectual and social capacity to comply with study visits and follow-up requirements

Exclusion criteria

• Presence of inflammatory arthritis, septic arthritis, crystal arthropathy, or secondary causes of knee osteoarthritis
• Kellgren-Lawrence grade 4 knee osteoarthritis
• Active systemic infection
• History of malignancy
• Intra-articular knee injection within the past 3 months
• Knee trauma within the past 3 months
• History of knee surgery
• Contraindications to aspiration or corticosteroid injection (e.g., local infection, bleeding disorders, uncontrolled diabetes mellitus)
• Requirement to continue medications for inflammatory arthritis
• Diagnosed psychiatric disorder that may impair study participation
• Use of nonsteroidal anti-inflammatory drugs (NSAIDs) within the past 1 week
• Physical therapy applied to the knee region within the past 1 month

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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44 participants in 2 patient groups

Aspiration + Steroid-Lidocaine

Active Comparator group

Description:

Ultrasound-guided aspiration of Baker's cyst followed by injection of corticosteroid and lidocaine mixture. No fenestration is performed.

Treatment:

Drug: Steroid-Lidocaine Injection

Procedure: Baker's Cyst Aspiration

Arm Title: Aspiration + Steroid-Lidocaine + Fenestration

Experimental group

Description:

Ultrasound-guided aspiration followed by corticosteroid-lidocaine injection and fenestration using multiple needle perforations under real-time ultrasound guidance.

Treatment:

Drug: Steroid-Lidocaine Injection

Procedure: Ultrasound-Guided Fenestration

Procedure: Baker's Cyst Aspiration