The Effectiveness of High-intensity Laser Therapy on Post-surgical Rehabilitation After Total Knee Arthroplasty

April 28, 2026 updated by: Istituto Ortopedico Rizzoli

The Effectiveness of High-intensity Laser Therapy on Post-surgical Rehabilitation: a Randomized Controlled Trial

This randomized controlled trial aims to evaluate the effectiveness of high-intensity laser therapy (HILT) as an adjunct to conventional rehabilitation in patients undergoing total knee arthroplasty (TKA).

Persistent pain and functional limitations are common after TKA despite standard rehabilitation, highlighting the need for adjunctive therapies to optimize postoperative recovery. High-intensity laser therapy has been proposed as a non-invasive intervention with potential analgesic and anti-inflammatory effects; however, its effectiveness in this population remains unclear.

Participants will be randomly allocated to one of two groups: an experimental group receiving HILT in addition to conventional physiotherapy and a control group receiving sham laser therapy combined with the same rehabilitation program. Both groups will undergo standardized rehabilitation sessions lasting 60 minutes, including 15 minutes of active or sham laser therapy and 45 minutes of conventional physiotherapy.

The primary outcome is postoperative pain. Secondary outcomes include joint swelling, range of motion, muscle strength, physical function, and quality of life.

Assessments will be conducted at baseline (preoperative), at 1 month after surgery (prior to the start of rehabilitation), during the rehabilitation program (after the fourth, seventh, and tenth physiotherapy sessions), and at 4 months postoperatively (follow-up).

A total of 46 participants (23 per group) will be enrolled in the study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
46

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Italy
      • Bologna, Italy, 40136
        • IRCCS Istituto Ortopedico Rizzoli

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients undergoing primary unilateral total knee arthroplasty for primary knee osteoarthritis
  • Age between 50 and 80 years
  • Pain intensity greater than 30/100 on the Visual Analog Scale (VAS)
  • Ability and willingness to provide written informed consent

Exclusion Criteria:

  • Psychiatric disorders
  • Cognitive impairments
  • Previous major trauma or surgery involving the affected knee
  • Rheumatic diseases or fibromyalgia
  • Vascular diseases
  • Neoplastic diseases
  • Infectious diseases
  • Neurological disorders
  • Hemophilia or bleeding disorders
  • Current anticoagulant therapy
  • Presence of a pacemaker
  • History of epileptic seizures
  • Known hypersensitivity or contraindication to laser therapy
  • Suspected conditions in which tissue heating is contraindicated
  • Use of photosensitizing medications or known photosensitivity
  • Skin lesions or abrasions at the treatment site
  • Tattoos in the treatment area
  • Intra-articular steroid injections in the target knee within the previous 2-3 weeks
  • Recent significant trauma or injury
  • Use of anti-inflammatory or analgesic medications or other pain-relieving treatments (if not controlled or standardized)
  • Pregnancy or breastfeeding
  • Positive status for human immunodeficiency virus

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High level laser therapy group

High-intensity laser therapy (HILT) will be delivered using the HIRO TT device (ASA S.r.l.), which employs a patented pulsed laser system (FDA-approved in 2003) based on a solid-state Nd:YAG source emitting near-infrared (NIR) radiation at a wavelength of 1064 nm. The device operates with a mean power of 10.5 W and a peak power of 3 kW.

Three treatment areas (each measuring 15 × 10 cm) will be targeted: two longitudinal areas over the quadriceps muscle and one transverse area over the knee joint.

The treatment will be delivered at a frequency of 15 Hz, with a total energy dose of 2000 J, corresponding to an energy density of 4.5 J/cm². The total treatment time will be 14 minutes and 30 seconds.
Device: High level laser therapy

High-intensity laser therapy (HILT) will be delivered using the HIRO TT device (ASA S.r.l.), which employs a patented pulsed laser system (FDA-approved in 2003) based on a solid-state Nd:YAG source emitting near-infrared (NIR) radiation at a wavelength of 1064 nm. The device operates with a mean power of 10.5 W and a peak power of 3 kW.

Three treatment areas (each measuring 15 × 10 cm) will be targeted: two longitudinal areas over the quadriceps muscle and one transverse area over the knee joint.

The treatment will be delivered at a frequency of 15 Hz, with a total energy dose of 2000 J, corresponding to an energy density of 4.5 J/cm². The total treatment time will be 14 minutes and 30 seconds.
Sham Comparator: Sham laser therapy group

The sham laser intervention will be delivered using the same HIRO TT device and identical treatment procedures as the active HILT group.

The same anatomical areas (two longitudinal areas over the quadriceps muscle and one transverse area over the knee joint) will be targeted, with identical session duration and positioning.

During sham treatment, the device will remain switched on; however, no therapeutic laser emission will be delivered. This approach is intended to ensure participant blinding by replicating the visual and procedural aspects of the active intervention without providing any active therapeutic effect.
Other: Sham laser therapy

The sham laser intervention will be delivered using the same HIRO TT device and identical treatment procedures as the active HILT group.

The same anatomical areas (two longitudinal areas over the quadriceps muscle and one transverse area over the knee joint) will be targeted, with identical session duration and positioning.

During sham treatment, the device will remain switched on; however, no therapeutic laser emission will be delivered. This approach is intended to ensure participant blinding by replicating the visual and procedural aspects of the active intervention without providing any active therapeutic effect.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Visual Analogue Scale
Time Frame: after 3 weeks
The VAS consists of a 100-mm horizontal line anchored by two descriptors: "no pain" (0 mm) and "worst imaginable pain" (100 mm). Participants will be asked to mark a point on the line corresponding to their perceived level of pain. The score will be determined by measuring the distance in millimeters from the left end of the line to the patient's mark, with higher scores indicating greater pain intensity.
after 3 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Visual Analogue Scale
Time Frame: Baseline, after 1 week, after 2 weeks, after 4 months follow-up
The VAS consists of a 100-mm horizontal line anchored by two descriptors: "no pain" (0 mm) and "worst imaginable pain" (100 mm). Participants will be asked to mark a point on the line corresponding to their perceived level of pain. The score will be determined by measuring the distance in millimeters from the left end of the line to the patient's mark, with higher scores indicating greater pain intensity.
Baseline, after 1 week, after 2 weeks, after 4 months follow-up
Range of Motion
Time Frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Knee range of motion (ROM) will be assessed bilaterally, both actively and passively, including maximum flexion and full extension.

Measurements will be obtained using a digital goniometer. The axis of rotation will be aligned with the lateral femoral condyle. The stationary arm will be aligned with the longitudinal axis of the femur, using the greater trochanter as a proximal reference point, while the movable arm will be aligned with the longitudinal axis of the fibula, using the fibular head and lateral malleolus as reference points.

ROM values will be recorded in degrees, with higher flexion values and lower extension deficits indicating better joint mobility.
Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up
Swelling
Time Frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Knee swelling will be assessed using circumferential measurements (cm) obtained with a flexible measuring tape.

Measurements will be performed with the participant in the supine position and the lower limbs in full extension. Circumference will be recorded at standardized anatomical landmarks: 1 cm below the inferior pole of the patella (knee joint line), 10 cm and 20 cm above the patellar base, and 5 cm below the patellar apex.

Two measurements will be taken at each site, and the mean value will be used for analysis. Higher circumference values will indicate greater swelling.
Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up
Lower limb muscle strength
Time Frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Lower limb muscle strength will be assessed using a handheld dynamometer during isometric knee extension and flexion of the operated limb.

Participants will perform three maximal voluntary isometric contractions for each movement, each lasting 5 seconds, with a 30-second rest interval between repetitions. The mean value of the three trials will be used for analysis.

For knee extension assessment, participants will be seated with the hip and knee flexed at 90°. For knee flexion assessment, participants will be positioned prone with the knee flexed at 90°. In both conditions, limb positioning will be standardized using a digital goniometer and stabilized with a fixation strap.

The dynamometer will be placed at the distal third of the leg, approximately 10 cm proximal to the ankle joint. The device will be manually stabilized by the assessor to ensure consistent positioning and minimize compensatory movements.

Higher values will indicate greater muscle strength.
Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up
Western Ontario and McMaster Universities Osteoarthritis Index
Time Frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

The WOMAC is a patient-reported outcome measure specifically designed for individuals with knee osteoarthritis. It consists of three subscales assessing pain, stiffness, and physical function. The physical function subscale includes items related to activities of daily living such as walking, stair use, sitting, and standing.

Each item is scored on a Likert scale, and total scores are calculated by summing item responses. Higher scores indicate worse pain, stiffness, and functional limitation.
Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Istituto Ortopedico Rizzoli

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 28, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 5, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 5, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • LASER_KNEE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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