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Completed

NCT Number: NCT07630259

Effects of High-Intensity Laser Therapy Combined With Exercise in Patients With Knee Osteoarthritis

The goal of this clinical trial was to determine whether high-intensity laser therapy (HILT) combined with exercise improves pain, physical function, and muscle strength in people with knee osteoarthritis.

The main questions the study aimed to answer were:

* Did HILT combined with exercise lower pain more than sham laser combined with exercise? * Did HILT combined with exercise improve physical function more than sham laser combined with exercise? * Did HILT combined with exercise improve knee extensor muscle strength more than sham laser combined with exercise?

Researchers compared HILT plus exercise with sham laser plus exercise to determine whether HILT provided additional benefits beyond those achieved with exercise alone.

Participants:

* Received either HILT or sham laser treatment for four weeks. * Participated in a standardized exercise program. * Completed assessments of pain, physical function, and muscle strength before and after treatment.

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Key information

Conditions

Osteoarthritic Knee Pain Arthritis Joint Diseases Musculoskeletal Diseases Neurologic Manifestations Osteo Arthritis of the Knee Osteoarthitis Osteoarthritis Osteoarthritis (Knee) Osteoarthritis (OA) of the Knee Osteoarthritis in the Knee Osteoarthritis, Knee Pain Pathological Conditions, Signs and Symptoms Rheumatic Diseases Signs and Symptoms

Age range

45 year–77 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Departamento de Kinesiología

Santiago, Santiago Metropolitan, 7760197, Chile

About this study

Knee osteoarthritis is a common musculoskeletal condition associated with pain, reduced physical function, and muscle weakness. Exercise therapy is widely recommended as a first-line treatment; however, the additional benefits of high-intensity laser therapy (HILT) remain uncertain. Previous studies have reported improvements in pain and function following HILT, but results have been inconsistent, and its effects on muscle strength have not been fully established.

The purpose of this randomized, participant-blinded, sham-controlled clinical trial was to evaluate the effects of HILT combined with exercise on pain, physical function, and knee extensor muscle strength in people with knee osteoarthritis.

Participants with clinically diagnosed knee osteoarthritis were randomly assigned to one of two groups. The experimental group received HILT combined with a standardized exercise program, while the control group received sham laser treatment combined with the same exercise program. The intervention lasted four weeks and included ten treatment sessions.

Pain intensity, physical function, and knee extensor muscle strength were assessed before and after the intervention using validated clinical outcome measures. The primary objective was to determine whether HILT provides additional benefits beyond those achieved with exercise alone.

The findings of this study may help clarify the role of HILT as an adjunct treatment in rehabilitation programs for people with knee osteoarthritis and contribute to the development of evidence-based clinical recommendations.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Clinical diagnosis of knee osteoarthritis.
  • Age between 45 and 77 years.
  • Pain intensity of at least 3 points on the Visual Analogue Scale (VAS).

Exclusion criteria

  • Presence of other musculoskeletal conditions affecting the lower limbs.
  • History of lower limb surgery.
  • Tattoos in the laser application area.
  • Recent intra-articular corticosteroid injection.
  • Comorbidities limiting participation in physical exercise, such as chronic obstructive pulmonary disease, stroke, or severe heart failure.

Treatment and study plan

High intensity laser therapy

Device

High-intensity laser therapy (HILT) was delivered using an MLS laser device (MPHI D, ASA Laser, Italy), which combines synchronized 808 nm and 905 nm wavelengths. Treatment was applied to four periarticular knee regions, including the medial and lateral patellar borders, the suprapatellar region, and the medial tibiofemoral joint line. Participants received 10 treatment sessions over four weeks. HILT was administered in combination with a standardized exercise program.

Other names: HILT, MLS Laser Therapy, Photobiomodulation, Laser Therapy

sham laser

Device

Sham laser treatment was delivered using the same laser device, treatment schedule, and application sites as the active intervention. Subtherapeutic parameters were used to mimic the treatment procedure while minimizing biological effects and maintaining participant blinding. Participants received 10 treatment sessions over four weeks in combination with the same standardized exercise program used in the experimental group.

Other names: Sham Laser Therapy, Placebo Laser, Sham High Intensity Laser Therapy

Exercise

Other

The exercise program was performed during each treatment session and included strengthening, flexibility, and balance exercises targeting the lower extremities. Exercises included stationary cycling, hamstring and gastrocnemius stretching, straight-leg raises, knee extensions, heel raises, step-ups, and single-leg balance activities. The program was standardized for both study groups and was delivered over 10 sessions during a four-week period.

Other names: Therapeutic exercise, Exercise Program, Physical Therapy exercise, Rehabilitation exercise

Primary outcomes

  1. Change From Baseline in Knee Extensor Muscle Strength After 4 Weeks of Treatment

    Time frame: Baseline and Week 4

    Change in knee extensor muscle strength measured with a dynamometer. Results were expressed in Newtons (N). Higher values indicate greater muscle strength.

Secondary outcomes

  1. Change From Baseline in Pain Intensity After 4 Weeks of Treatment

    Time frame: Baseline and Week 4

    Change in pain intensity measured using the Visual Analogue Scale (VAS). Scores range from 0 to 10, with higher scores indicating greater pain intensity.

  2. Change From Baseline in WOMAC Total Score After 4 Weeks of Treatment

    Time frame: Baseline and Week 4

    Change in symptoms and functional status measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Higher scores indicate greater impairment.

Sponsors and collaborators

Lead sponsor

Universidad Metropolitana de Ciencias de la Educacion

Other

Registry information

Official study title

Effects of High-intensity Laser Therapy on Muscle Strength in People With Knee Osteoarthritis

Acronym: HILT-KOA

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Jun 5, 2026
Registry last updated
Jun 5, 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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