Dose-Response Effect of Intra-Articular Ozone in Knee Osteoarthritis

Dose-Response Effect of Intra-Articular Ozone in Knee Osteoarthritis: A Randomized Controlled Single-Blind Clinical Study

The goal of this clinical trial is to evaluate the clinical efficacy of different doses of intra-articular ozone injections combined with exercise in patients aged 40-75 diagnosed with Grade 2-3 knee osteoarthritis.

The main questions it aims to answer are:

• Which intra-articular ozone doses (10 µg/mL, 15 µg/mL, or 20 µg/mL) is most effective in improving pain and physical function in knee osteoarthritis?
• Do combined ozone and exercise therapies provide superior clinical outcomes compared to exercise therapy alone? Researchers will compare four groups (Ozone 10 µg/mL + Exercise, Ozone 15 µg/mL + Exercise, Ozone 20 µg/mL + Exercise and Exercise Alone) to see the dose-dependent effects of ozone therapy.

Participants will:

• Complete a structured home exercise program for the duration of the study.
• Receive 3 sessions of intra-articular ozone injections (for patients allocated to the ozone groups).
• Participate follow-up visits for clinical and functional assessments at baseline (before the procedure), immediately after the 3rd injection session, at 1 month after the last ozone injection, and at 3 months after the last ozone injection.

Study Overview

• Status: Recruiting
• Conditions: Knee Osteoarthritis
• Intervention / Treatment: Other: ozone injection; Behavioral: Exercise

Detailed Description

This clinical trial is designed as a prospective, randomized, controlled study to investigate the dose-dependent therapeutic effects of intra-articular ozone therapy in patients with Grade 2-3 knee osteoarthritis.

Eligible participants aged 40-75 with a confirmed diagnosis of knee osteoarthritis (Kellgren-Lawrence Grade 2 or 3) will be recruited. Participants will be allocated into one of four parallel groups by computerized randomization.

All patients allocated to the ozone intervention groups will receive a total of 3 sessions of intra-articular ozone injections, administered once a week for three consecutive weeks. For all three treatment groups, the injection volume will be at 10 mL per session, while the ozone concentrations will vary according to the assigned group as follows:

Ozone 10 µg + Exercise: 10 mL of ozone injection at a concentration of 10 µg/mL + Home exercise program.

Ozone 15 µg + Exercise: 10 mL of ozone injection at a concentration of 15 µg/mL + Home exercise program.

Ozone 20 µg + Exercise: 10 mL of ozone injection at a concentration of 20 µg/mL + Home exercise program.

Exercise Alone (Control): Home exercise program alone.

All participants across all four groups will be prescribed a structured home exercise program. This program includes joint range of motion (ROM) exercises; strengthening exercises and flexibility exercises.

The home program will be performed for 30 minutes per day, 5 days a week, throughout the 3-month study period. To improve patient adherence to exercise, patients will be provided with an exercise diary and also an analgesic diary to track analgesic use.

Clinical and functional evaluations will be performed at four distinct time points: baseline (pre-treatment), immediately after the 3rd injection session (post-treatment), 1 month after the last ozone injection, and 3 months after the last ozone injection. The clinical and functional status of the participants will be evaluated using the Numerical Rating Scale (NRS) for pain severity, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for knee-specific symptoms and physical function, the Lequesne Algofunctional Index for osteoarthritis severity and physical disability, and the EuroQol 5-Dimension (EQ-5D) questionnaire for overall health-related quality of life. Additionally, objective functional capacity, dynamic balance, and mobility will be assessed using the 6-Minute Walk Test (6MWT) and the Timed Up and Go (TUG) test.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Serhat Efdal Ozbek, MD; Phone Number: +905072387257; Email: serhatefdal60@gmail.com

Study Locations

• Turkey (Türkiye)
  • Kayseri, Turkey (Türkiye), 38080
    • Recruiting
    • Kayseri City Hospital
    • Contact: Serhat Efdal Ozbek, MD; Phone Number: +905072387257; Email: serhatefdal60@gmail.com
    • Sub-Investigator: Serhat Efdal Ozbek, MD
    • Principal Investigator: Fatma Gul Ulku Demir, MD
    • Sub-Investigator: Havva Talay Calis, Professor

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients aged 40-75 years diagnosed with knee osteoarthritis according to the American College of Rheumatology 2019 criteria
• Grade 2 or 3 knee osteoarthritis based on the Kellgren-Lawrence radiological classification system.
• Presence of chronic knee pain lasting for more than 6 months.
• Numerical Rating Scale score of 3 or higher during knee-loading activities

Exclusion Criteria:

• Presence or history of acute knee infection, major knee trauma, or inflammatory arthritis
• History of knee fracture or surgical intervention involving the affected knee joint within the last 6 months.
• History of intra-articular injections (e.g., corticosteroids, hyaluronic acid, PRP) into the affected knee joint within the last 6 months.
• History of physical therapy or rehabilitation in the knee region within the last 6 months
• Presence of osteomyelitis adjacent to the knee joint, bacteremia, or hemarthrosis.
• History of malignancy involving the lower extremity.
• Known hypersensitivity or allergy to medical ozone.
• Severe anemia, thrombocytopenia, active bleeding disorders, or ongoing anticoagulant therapy.
• Pregnancy or lactation
• Active infection
• Severe systemic diseases (e.g., advanced cardiopulmonary disease, uncontrolled diabetes mellitus).
• Hyperthyroidism or progressive neuromuscular disorders.
• Cognitive impairment or inability to cooperate with the assessment tools and study protocol.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 10 µg Ozone + Exercise; 10 mL of ozone injection at a concentration of 10 µg/mL + Home exercise program	Other: ozone injection; All patients allocated to the ozone intervention groups will receive a total of 3 sessions of intra-articular ozone injections, administered once a week for three consecutive weeks. For all three treatment groups, the injection volume will be 10 mL per session, while the ozone concentrations will vary according to the assigned group as Ozone 10 µg/mL + Exercise, Ozone 15 µg/mL + Exercise, and Ozone 20 µg/mL + Exercise.; Other Names: Intra-articular Ozone Injection; Behavioral: Exercise; All participants across all four groups will be prescribed a structured home exercise program. This program includes joint range of motion (ROM) exercises; strengthening exercises (including quadriceps strengthening, hamstring strengthening, hip abductor strengthening, and seated calf raises); and flexibility exercises (including hamstring stretching, gastrocnemius-soleus stretching, and quadriceps stretching). The home program will be performed for 30 minutes per day, 5 days a week, throughout the 3-month study period. To improve patient adherence to exercise, patients will be provided with an exercise diary.
Experimental: 15 µg Ozone + Exercise; 10 mL of ozone injection at a concentration of 15 µg/mL + Home exercise program	Other: ozone injection; All patients allocated to the ozone intervention groups will receive a total of 3 sessions of intra-articular ozone injections, administered once a week for three consecutive weeks. For all three treatment groups, the injection volume will be 10 mL per session, while the ozone concentrations will vary according to the assigned group as Ozone 10 µg/mL + Exercise, Ozone 15 µg/mL + Exercise, and Ozone 20 µg/mL + Exercise.; Other Names: Intra-articular Ozone Injection; Behavioral: Exercise; All participants across all four groups will be prescribed a structured home exercise program. This program includes joint range of motion (ROM) exercises; strengthening exercises (including quadriceps strengthening, hamstring strengthening, hip abductor strengthening, and seated calf raises); and flexibility exercises (including hamstring stretching, gastrocnemius-soleus stretching, and quadriceps stretching). The home program will be performed for 30 minutes per day, 5 days a week, throughout the 3-month study period. To improve patient adherence to exercise, patients will be provided with an exercise diary.
Experimental: 20 µg Ozone + Exercise; 10 mL of ozone injection at a concentration of 20 µg/mL + Home exercise program	Other: ozone injection; All patients allocated to the ozone intervention groups will receive a total of 3 sessions of intra-articular ozone injections, administered once a week for three consecutive weeks. For all three treatment groups, the injection volume will be 10 mL per session, while the ozone concentrations will vary according to the assigned group as Ozone 10 µg/mL + Exercise, Ozone 15 µg/mL + Exercise, and Ozone 20 µg/mL + Exercise.; Other Names: Intra-articular Ozone Injection; Behavioral: Exercise; All participants across all four groups will be prescribed a structured home exercise program. This program includes joint range of motion (ROM) exercises; strengthening exercises (including quadriceps strengthening, hamstring strengthening, hip abductor strengthening, and seated calf raises); and flexibility exercises (including hamstring stretching, gastrocnemius-soleus stretching, and quadriceps stretching). The home program will be performed for 30 minutes per day, 5 days a week, throughout the 3-month study period. To improve patient adherence to exercise, patients will be provided with an exercise diary.
Active Comparator: Exercise Alone; Home exercise program alone	Behavioral: Exercise; All participants across all four groups will be prescribed a structured home exercise program. This program includes joint range of motion (ROM) exercises; strengthening exercises (including quadriceps strengthening, hamstring strengthening, hip abductor strengthening, and seated calf raises); and flexibility exercises (including hamstring stretching, gastrocnemius-soleus stretching, and quadriceps stretching). The home program will be performed for 30 minutes per day, 5 days a week, throughout the 3-month study period. To improve patient adherence to exercise, patients will be provided with an exercise diary.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Numerical Rating Scale at Third Month after the last ozone injection	The Numerical Rating Scale is an 11-point segment scale used to evaluate the severity of knee joint pain. Scores range from 0 to 10, where 0 indicates "no pain" and 10 indicates "the worst possible pain."	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knee-specific symptoms and physical function-WOMAC	The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a self-administered questionnaire specific to knee osteoarthritis, consisting of 24 items divided into 3 subscales: Pain (5 items), Stiffness (2 items), and Physical Function (17 items). Total scores range from 0 to 96, with higher scores indicating worse symptoms and greater physical limitation. Lower scores represent better functional improvement.	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.
Osteoarthritis severity and physical disability- Lequesne Algofunctional Index	The Lequesne Index is used to assess the severity of knee osteoarthritis and the level of physical disability. It includes questions regarding pain, maximum walking distance, and daily living activities. The total score ranges from 0 to 24. Higher scores indicate more severe osteoarthritis.	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.
Overall health-related quality of life- EuroQol 5-Dimension (EQ-5D) questionnaire	The EQ-5D questionnaire evaluates general health-related quality of life across 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Scores are converted into an index score ranging from less than 0 to 1. Higher scores indicate a better quality of life.	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.
6-Minute Walk Test (6MWT)	The 6MWT is an objective clinical test used to assess functional capacity and dynamic mobility. Patients are instructed to walk as far as possible along a straight corridor in 6 minutes. The total distance covered is measured in meters. An increase in the walking distance indicates an improvement in functional mobility.	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.
Timed Up and Go (TUG) Test	The TUG test is used to evaluate dynamic balance, mobility, and fall risk. Patients are timed as they rise from a standard chair, walk 3 meters, turn around, walk back to the chair, and sit down. The outcome is recorded in seconds. Shorter completion times represent better balance and mobility.	Baseline, Week 2 (immediately after the 3rd injection session), 1 month after the last ozone injection, and 3 months after the last ozone injection.

Collaborators and Investigators

• Sponsor: Kayseri City Hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 19, 2025
• Primary Completion (Estimated): November 30, 2026
• Study Completion (Estimated): November 30, 2026

Study Registration Dates

• First Submitted: June 16, 2026
• First Submitted That Met QC Criteria: June 30, 2026
• First Posted (Actual): July 1, 2026

Study Record Updates

• Last Update Posted (Actual): July 1, 2026
• Last Update Submitted That Met QC Criteria: June 30, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: osteoarthritis; knee; ozone
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Inorganic Chemicals; Gases; Oxygen; Exercise; Ozone
• Other Study ID Numbers: Kayseri-GETAT-2025-102

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No