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

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.

Conditions

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

Interventions

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.

Sponsors & Collaborators

• Istanbul University - Cerrahpasa

  lead OTHER

Principal Investigators

• TUTKU NAZ BULUT, MD · Istanbul University - Cerrahpasa

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

40 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-02-15

Primary Completion

2026-05-30

Completion

2026-05-30

Countries

• Turkey (Türkiye)

Study Locations