Ultrasound-guided Injection of Glucocorticoid Into Infrapatellar Fat Pad in Patients With Knee Osteoarthritis

Inclusion criteria

• Diagnosed with symptomatic knee osteoarthritis (OA) according to American College of Rheumatology criteria;
• Age > 45 years;
• Have knee pain for more than six months and the knee pain over the past week assessed by VAS (100 mm) ≥ 40 mm;
• Ultrasonography showed obvious synovitis with effusion in the knee joint;
• Both MRI-assessed Hoffa-synovitis score (MOAKS method) and effusion-synovitis score (modified WORMS method) ≥ 1, and their total score ≥ 3;
• Being able to listen, speak, read and understand Chinese, capable of understanding the study requirements and cooperating with the researchers during the study, and providing written informed consent.

Exclusion criteria

• Allergy to glucocorticoids;
• Knee injection of glucocorticoid or hyaluronic acid within the past six months;
• Severe trauma or arthroscopy in the knee within the past six months;
• Planned hip or knee surgery (including arthroscopy, arthroplasty, and other open joint surgeries) in the next six months;
• Contraindication to having magnetic resonance imaging (MRI) (e.g., implanted pacemaker, artificial metal valve or cornea, aneurysm clipping surgery, arterial dissection, metal foreign bodies in the eyeball, claustrophobia);
• Presence of other arthritis, such as rheumatoid arthritis and psoriatic arthritis;
• Other physical condition that is more painful than their knee OA;
• Malignant tumors or other life-threatening diseases;
• Infection, diabetes, coagulopathy, osteonecrosis, or gastric/duodenal ulcer within the past 12 months;
• Current use of oral corticosteroids, nonsteroidal anti-inflammatory drugs, or immunosuppressive medication;
• Pregnancy or lactating female;
• Use any investigational drugs or devices in the recent 30 days.