Double-Blind Randomized Controlled Trial Comparing the Effectiveness of Two Standardized Radial Pressure Wave Techniques Versus Pain-Site Guided Therapy in Patients With Knee Osteoarthritis.

Methods Patients The study will enroll patients between the ages of 50 and 80 years with chronic and current knee pain and a clinical and radiographic diagnosis of knee osteoarthritis (OA). Participants will be recruited through the "Treatment of Knee OA with Radial Pressure Wave Therapy" campaign conducted by the Physical Medicine and Rehabilitation Department of the Hospital Civil de Guadalajara "Fray Antonio Alcalde" in México. Recruitment will take place during the months of August and September 2024. Individuals with a history of knee surgery, inflammatory arthritis, septic arthritis, fibromyalgia, cancer, or severe vascular insufficiency will be excluded from participation in this study.

Ethical Statement The participants will be required to sign an informed consent form which will include all details of the study. The patients will be free to decide whether or not to participate or to withdraw from the protocol at any time. The study was approved by the Research Ethics Committee of the Hospital Civil de Guadalajara Fray Antonio Alcalde (number: CEI 157/24) and was conducted in accordance with the World Medical Association's Declaration of Helsinki.

Randomization After obtaining written informed consent, the participants will be randomized to one of three treatment groups: radial pressure wave therapy (RPWT) at the two most painful points (control group), RPWT at the medial interarticular line (medial group), or RPWT at the medial and lateral interarticular lines (medial and lateral group). Randomization will be performed using the paper envelope randomization method. For this purpose, the investigators will prepare a series of opaque papers, each indicating one of the three possible assignments. These papers will be placed in an opaque bag, and during the enrollment process, each patient will randomly draw a paper from the bag. The patient's group assignment will be determined by the label on the paper drawn.

Treatment The three groups will receive RPWT using the BTL-6000 Radial Shockwave Therapy device (BTL Industries, Ltd.). Each patient will receive 3 sessions of RPW, once a week, in the supine position with knee flexion of 30 to 60 degrees, 2,000 pulses per session, 2.0 bar, and frequency of 10 Hz. The air pressure and frequency will be adjusted according to discomfort. The control group will receive 1,000 pulses to the two most painful areas of the treated knee, according to the technique used in most previous studies in this area. The medial group will receive 2,000 pulses at the medial interarticular line of the treated knee, while the medial and lateral groups will receive 1,000 pulses at the medial interarticular line and 1,000 pulses at the lateral interarticular line of the treated knee. All participants will be trained to perform a home exercise program for 4 consecutive weeks, three sessions per week, consisting of superficial thermotherapy for 10 minutes, hamstring and quadriceps stretching, medial gluteus medius and quadriceps strengthening, and propioception exercises. The interventions will be performed at the Physical Medicine and Rehabilitation Department of the Civil Hospital of Guadalajara "Fray Antonio Alalde". Complications, adverse effects and complaints during treatment will be documented.

Outcome measures A questionnaire will be used to assess sociodemographic characteristics, including age, gender, and education level for all patients. In addition, the numerical and categorical forms of body mass index (BMI), physical activity habits, and analgesic use will be assessed after eligibility criteria are established using the aforementioned instrument. The severity of knee OA will also be measured by a board-certified rheumatologist using the Kellgren & Lawrence scale.