This observational study aims to identify baseline factors that predict clinical response at six months in patients with knee osteoarthritis treated with radial pressure wave therapy (rESWT). The study is a secondary analysis of data obtained from a randomized double-blind clinical trial conducted in 2024 at a tertiary care hospital in Mexico.

Knee osteoarthritis is a common condition that causes pain, stiffness, and reduced physical function. Radial pressure wave therapy is a non-invasive treatment that has shown benefits in improving symptoms; however, not all patients respond equally.

This study will analyze patient characteristics at baseline, such as age, body mass index, pain severity, and functional status, to determine which factors are associated with meaningful improvement in pain and function after treatment. The results may help clinicians better identify which patients are more likely to benefit from this therapy and improve personalized treatment decisions.

Background: Knee osteoarthritis (OA) is a leading cause of pain and disability worldwide. It is characterized by progressive joint degeneration, resulting in pain, stiffness, and functional limitations. Radial pressure wave therapy (rESWT) is a non-invasive treatment that has demonstrated effectiveness in reducing pain and improving function in patients with knee OA. However, there is significant variability in patient response, and the factors that predict treatment success are not well established.

Objective: The aim of this study is to identify baseline predictors of clinical response at six months in patients with knee OA treated with rESWT.

Methods: This study is a secondary analysis of a randomized double-blind clinical trial conducted in 2024 at the Antiguo Hospital Civil de Guadalajara "Fray Antonio Alcalde". The original trial evaluated the effectiveness of three standardized rESWT protocols in patients with knee OA. The present study is designed as an observational cohort analysis including patients with complete baseline and follow-up data.

Baseline variables include demographic characteristics (age, sex), clinical factors (body mass index, baseline pain intensity, functional status), and radiographic severity. The primary outcome is the achievement of the minimal clinically important difference (MCID) in the WOMAC score at six months. Secondary outcomes include MCID in pain intensity measured by the Numerical Pain Rating Scale (NPRS) and changes in WOMAC and NPRS scores over time.

Statistical analyses will be conducted to identify independent predictors of clinical response and to explore the interaction between baseline characteristics and treatment protocols.

Significance: Identifying predictors of response to rESWT may improve patient selection, optimize treatment strategies, and contribute to more personalized and cost-effective care in patients with knee osteoarthritis.

Inclusion Criteria:

• Clinical and radiographic diagnosis of knee osteoarthritis
• Participation in the original randomized double-blind clinical trial evaluating radial pressure wave therapy (rESWT) in 2024
• Availability of complete baseline data
• Availability of follow-up data up to 6 months

Exclusion Criteria:

• Incomplete baseline or follow-up data
• Withdrawal from the original trial before completion
• Missing outcome measurements required for analysis
• Presence of conditions that could interfere with outcome assessment or data validity

Adult patients with clinically and radiographically confirmed knee osteoarthritis who participated in a randomized double-blind clinical trial evaluating radial pressure wave therapy (rESWT) at a tertiary care hospital in Mexico in 2024. Only participants with complete baseline and six-month follow-up data are included in this secondary analysis.