Extracorporeal Shock Wave Therapy in the Treatment of Periarticular Bone Marrow Edema in Patients With Knee Osteoarthritis

Bone marrow edema (BME) is a radiological finding characterized by increased fluid content and structural changes within the bone marrow. It most commonly affects weight-bearing joints such as the hip, knee, and ankle. Patients with BME may present with pain during activity or at rest, tenderness, swelling, joint effusion, and limitation of joint motion. Magnetic resonance imaging (MRI) is considered the gold standard for diagnosis. BME is commonly observed in patients with knee osteoarthritis (OA) and may be associated with increased pain, impaired joint function, and progression of structural joint damage. Therefore, recognition and treatment of BME may be clinically important in patients with knee OA. Treatment options for BME include conservative and surgical approaches. Standard conservative treatment generally includes activity and weight-bearing modification, analgesics and nonsteroidal anti-inflammatory drugs, and physical therapy modalities. Extracorporeal shock wave therapy (ESWT) is one of the non-invasive physical therapy options that can be added to standard conservative treatment. Surgical treatment, including core decompression, may be considered in patients who do not respond to conservative treatment. ESWT may exert beneficial effects by improving local blood flow, promoting angiogenesis, stimulating bone remodeling and regeneration, and providing analgesia. Previous studies in patients with knee-related BME have suggested that ESWT may reduce pain, improve functional outcomes, and decrease BME findings on MRI. Kang et al. reported more rapid improvements in pain, functional outcomes, and the MRI-detected area of BME within three months with ESWT compared with alendronate therapy. Sansone et al. found that ESWT resulted in greater reductions in pain and BME area, together with clinically meaningful improvement at three months, compared with conservative treatment consisting of unloading and analgesics. In a prospective randomized controlled trial, Gao et al. further showed that ESWT provided more favorable six-month outcomes in terms of pain, functional scores, and MRI-assessed BME area than intravenous prostacyclin combined with oral bisphosphonate therapy. Collectively, these findings suggest that ESWT may provide sustained clinical and radiological benefits in patients with knee BME. This study aims to investigate the effects of adding ESWT to standard conservative treatment in patients with knee osteoarthritis accompanied by bone marrow edema. Patients receiving active ESWT will be compared with those receiving sham ESWT in terms of pain, functional outcomes, patient satisfaction, and changes in bone marrow edema volume on MRI.

Inclusion Criteria: * Aged 40-70 years * Radiographic evidence of knee osteoarthritis classified as Kellgren-Lawrence grade 2 or 3 * Unilateral BME in the bones around the knee, limited to either the medial or lateral compartment of the knee joint, as confirmed by MRI. The affected sites may include the medial femoral condyle, medial tibial plateau, or both; or the lateral femoral condyle, lateral tibial plateau, or both * Willingness to participate in the study * Provision of written informed consent Exclusion Criteria: * Insufficient cognitive ability to complete the questionnaires * Physical therapy, corticosteroid injection, or surgery involving the affected area within the previous 6 months * Previous ESWT treatment * Open wounds, infection, bleeding, skin lesions, or metal implants around the knee * Presence of a cardiac pacemaker * Peripheral arterial occlusive disease * Polyneuropathy or sensory impairment * Inflammatory rheumatic disease * Severe cardiovascular disease * Pregnancy * History of epilepsy * History of malignancy * Bleeding disorders