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NCT Number: NCT06965946

Intermittent Hypoxia-Hyperoxia Combined With Physical Therapy for Knee Osteoarthritis

This randomized controlled trial aims to evaluate the effectiveness of combining intermittent hypoxia-hyperoxia therapy (IHHT) with conventional physical therapy in improving pain, function, gait, balance, and general health among patients with knee osteoarthritis. The study will be conducted at the Physical Therapy Department of Rehman Medical Institute, Peshawar, Pakistan, over a period of one year.

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Key information

Conditions

Osteo Arthritis Knee Arthritis Joint Diseases Musculoskeletal Diseases Osteoarthritis Osteoarthritis, Knee Rheumatic Diseases

Age range

45 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Rehman Medical Institute

Peshawar, Khyber Pakhtunkhwa, 25000, Pakistan

About this study

Osteoarthritis (OA) is a prevalent chronic condition that leads to joint pain, stiffness, and impaired mobility, particularly among middle-aged and elderly populations. In Pakistan, knee OA is common and significantly impacts quality of life. Existing treatments are largely symptomatic and often insufficient, especially in resource-constrained settings.

Intermittent hypoxia-hyperoxia training (IHHT), involving alternating periods of low (13-15%) and high (40%) oxygen concentrations, has shown promise in improving physical and psychological outcomes in musculoskeletal disorders. However, evidence regarding its efficacy in knee OA is scarce, especially in low- and middle-income countries.

This trial seeks to explore whether the combination of IHHT and conventional physical therapy leads to superior improvements in clinical outcomes compared to conventional therapy alone. Participants will undergo 12 treatment sessions over 4 weeks. The primary outcome measures include pain (NPRS), function (KOOS), balance (Timed Up and Go Test), gait (Functional Gait Assessment), and inflammatory markers (CRP). The feasibility, safety, and effectiveness of this novel intervention will also be evaluated.

The study design includes assessor and participant blinding and uses rigorous methods including pre- and post-intervention assessments and statistical analysis with SPSS. Findings from this study may inform future guidelines for non-pharmacological, low-cost interventions for knee OA rehabilitation in similar contexts.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Participants aged 45 and above.
  • Participants (both male and female) with knee pain for 3 months or more with any three of the following six items: age of 50 years or more, crepitations, enlarged bone, no palpable warmth, morning stiffness for less than 30 minutes, and bony tenderness.
  • Patients who can walk and have a minimum score of 4 on the Numeric Pain Rating Scale.
  • Participants who have intact cognition with a score of 24 and above on Mini Mini- Mental State examination.
  • Participants able to walk independently for at least 45 meters in the 6-minute walk test.
  • Participants having a recent X-ray (done within the past 3 months).

Exclusion criteria

  • Patients with hip or knee arthroplasty.
  • Participants with above or below knee surgery or radiating pain to the lower limb.
  • Patients with history of epilepsy, pregnancy
  • Diagnosed neurological condition that affects lower-limb strength or walk (e.g., stroke/ basal ganglia dysfunction/ trauma)
  • Patients who refused to participate in the study or to be randomly allocated.
  • Patients receiving steroids or any medicine other than that prescribed by the screening orthopaedic surgeon.

Treatment and study plan

Intermittent Hypoxia-Hyperoxia Therapy (IHHT)

Procedure

Participants receive 4 cycles per session of 5 minutes of hypoxia (13-15% O₂) followed by 2 minutes of hyperoxia (40% O₂) using a hypoxia generator (Olive OLV 10H). Sessions are delivered before each conventional physical therapy session, 3 times per week for 4 weeks (total 12 sessions). Participants are monitored for heart rate, blood pressure, and oxygen saturation throughout the intervention.

Other names: Olive OLV 10H Hypoxia Generator

Conventional Physical Therapy

Procedure

Participants receive individualized conventional physical therapy for knee osteoarthritis based on current clinical practices in tertiary hospitals of Peshawar. Therapy is delivered 3 times per week for 4 weeks (total 12 sessions) and includes strength training, mobility exercises, and patient education.

Normoxic Air Placebo

Procedure

Participants in the control group inhale normoxic air (19.8% O₂) using the same Olive OLV 10H hypoxia generator to maintain blinding. Each session consists of 4 cycles of 5 minutes of normoxia followed by 2 minutes of normoxia, simulating the timing of hypoxia-hyperoxia therapy. Sessions are administered prior to conventional physical therapy, 3 times per week for 4 weeks (total 12 sessions). Patients are monitored for vital signs throughout.

Primary outcomes

  1. Pain Reduction

    Time frame: Baseline and 4 weeks (12 sessions of therapy)

    Measured on the Numeric Pain Rating Scale (NPRS), which has levels ranging from 0 to 10 in severity. 0 indicates no pain, and 10 indicates severe pain. The scale is divided into 3 categories. 1-3 indicates mild pain, 4-6 indicates moderate pain, and 7-10 indicates severe pain.

  2. Functional Status - KOOS Activities of Daily Living Subscale

    Time frame: Baseline and 4 weeks

    The Knee Injury and Osteoarthritis Outcome Score (KOOS) will be used to assess pain, recreation and quality of life, symptoms and stiffness, ADL and functional sports. The scores of each category will be calculated and converted to percentages (100%). 0-39% will indicate severe condition, 40- 59% will indicate moderate condition, 60-79% will indicate mild condition, and 80-100% will indicate no dysfunction.

  3. Inflammatory Marker - C-Reactive Protein (CRP)

    Time frame: Baseline and 4 weeks

    Change in serum CRP levels measured through a blood sample as a biomarker of osteoarthritis-related inflammation. CRP levels will be taken on a continuous scale.

  4. Balance - Timed Up and Go Test (TUG)

    Time frame: Baseline and 4 weeks

    Time taken (in seconds) to rise from a chair, walk 3 meters, turn, walk back, and sit down using a stop watch. A time of < or equal to 10 seconds will be considered normal, 11-20 seconds indicates good mobility with functional indipendence. > or equal to 20 seconds indicates that person needs assistance outside, 30 seconds or more indicates that person is prone to fall. MCID for time up and Go test is 2.1 seconds.

Secondary outcomes

  1. Gait Performance - Functional Gait Assessment (FGA) Score

    Time frame: Baseline and 4 weeks

    Evaluation of gait performance and stability using the FGA scale. Normal (score of 3) performances will be walking a distance of 6 meters in less than 5.5 seconds with no assistive device and no evidence of imbalance, a normal gait pattern, and not deviating more than 6 inches out of 12 12-inch walkway width. Mild impairment (score of 2) will be recorded when a person walks 6 meters with the use of an assistive device at a slower speed and mild gait deviation (15.24-25.4 cm) outside 12 12-inch walkway. Participants will be scored 1, moderate impairment, if they walk with a slower speed, abnormal gait pattern, evidence of imbalance, deviates 10-15 inches outside 12 12-inch walkway width. Participants will be said to have severe impairment, score of 0, if they can not walk 6 meters (20 feet) without assistance, severe gait deviations or imbalance, deviates greater than 15 inches outside 12 12-inch walkway width or will not attempt the task.

  2. Functional mobility - 6-Minute Walk Test (6MWT)

    Time frame: Baseline and 4 weeks

    Distance (in meters) covered during a 6-minute walk test to assess aerobic capacity and endurance. Normal score ranges from 400-700 meters. The participants will be asked to walk for 6 minutes, and the distance covered will be noted. The MCID for the 6-minute walk test is 45 meters.

Sponsors and collaborators

Lead sponsor

Khyber Medical University Peshawar

Other

Collaborators

  • Rehman Medical Institute - RMI

Registry information

Official study title

Effectiveness of Combining Intermittent Hypoxia-Hyperoxia and Conventional Physical Therapy for Patients With Knee Osteoarthritis: A Randomized Controlled Trial

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
May 11, 2025
Registry last updated
Jun 25, 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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