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NCT Number: NCT07662512

Different Ozone Concentrations for Knee Osteoarthritis

Knee osteoarthritis is a common condition that causes pain, stiffness, and difficulty with daily activities. Ozone injection therapy is a minimally invasive treatment that has been increasingly used to relieve symptoms in people with knee osteoarthritis. However, it is not clear whether different ozone concentrations produce different treatment outcomes.

In this study, we compared the effects of two commonly used ozone concentrations (15 μg/mL and 25 μg/mL) in patients with knee osteoarthritis. A total of 159 patients received intra-articular ozone injections and were followed for 3 months. Pain, physical function, and quality of life were assessed before treatment and at 1 and 3 months after the injections.

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Key information

Conditions

Knee Osteoarthristis Arthritis Gonarthrosis Joint Diseases Musculoskeletal Diseases Osteoarthritis Osteoarthritis, Knee Rheumatic Diseases

Age range

50 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Sakarya University

Adapazarı, Sakarya, 54010, Turkey (Türkiye)

About this study

Background: Knee osteoarthritis (KOA) is a prevalent joint disorder globally, resulting in pain and disability, with various treatment options available. Intra-articular ozone (O2-O3) administrations are an efficient therapeutic approach commonly employed in this condition. With this study, we aimed to compare the effect of varying ozone concentrations on treatment outcomes.

Method: This multicenter single-blind, cohort study was conducted at two distinct university hospitals between May 2023 and September 2024. Patients who underwent intra-articular knee ozone injection were examined and divided into two groups as 15 μg/ml (Group A) and 25 μg/ml ozone (Group B). Participants' pain scores were measured by Numeric Rating Scale (NRS), functional status by Western Ontario and McMaster Universities Arthritis Index (WOMAC) and quality of life by Short Form-12 (SF-12) before and at 1 and 3 months following ozone therapy.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients aged 50-85 years with a diagnosis of primary knee osteoarthritis according to the American College of Rheumatology [12] criteria, symptomatic knee with KL [13] grades II, III and IV, who underwent intra-articular ozone treatment.

Exclusion criteria

  • Patients with a history of any intra-articular injection within 3 months before the first ozone injection, a history of previous knee surgery, a diagnosis of malignancy, missing follow-up parameters, bilateral intra-articular knee ozone injection, a secondary knee osteoarthritis diagnosis (trauma, inflammatory joint disease, etc.), patients without demographic and clinical data, or direct radiographs.

Treatment and study plan

ozone injection

Other

Ozone (O2-O3) therapy is widely used in clinical practice as an alternative medical approach in the treatment of musculoskeletal diseases. Many recent studies have reported that intra-articular ozone implementation has a positive impact on knee osteoarthritis. Most available studies have focused on the comparison of ozone therapy with other intra-articular injections. However, the influence of the concentration and/or volume of the ozone used during injection on treatment outcomes has been omitted. The concentration of ozone administered into the joint varies, typically ranging from 15 to 30 μg/ml in these studies; however, there is no consensus regarding the appropriate dosage to be used. Based on this gap in the literature, we aimed to compare pain, functional status and quality of life among patients treated with different concentrations of intra-articular ozone therapy.

Primary outcomes

  1. Numeric rating scale (NRS)

    Time frame: prior to the procedure and at 1 and 3 months post-procedure.

    The NRS is a widely utilised tool for assessing and tracking pain severity. The rating scale consists of 11 points, where 0 signifies the absence of pain and 10 denotes the most excruciating pain imaginable. The patient is instructed to assess their pain on this scale from 0 to 10.

Secondary outcomes

  1. Western Ontario and McMaster Universities Arthritis Index (WOMAC)

    Time frame: prior to the procedure and at 1 and 3 months post-procedure.

    This questionnaire was developed to assess joint function associated with osteoarthritis and consists of three main sections: pain, stiffness, and physical function.

Other outcomes

  1. Short Form-12 (SF-12)

    Time frame: prior to the procedure and at 1 and 3 months post-procedure.

    This short form aims to measure the physical and mental health status of the patients and includes a total of 12 questions.

Sponsors and collaborators

Lead sponsor

Sakarya University

Other

Registry information

Official study title

Is Intra-articular Injection of High-concentration Ozone (O2-O3) More Effective in Treating Knee Osteoarthritis?: A Multicenter Clinical Trial

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Jun 23, 2026
Registry last updated
Jun 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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