Low Level Laser Therapy in Patients With Partial Anterior Cruciate Ligament Tear

University of Lahore

Status: Completed

Conditions: Anterior Cruciate Ligament (ACL) Tear

Treatments: Device: Low-Level Laser Therapy (LLLT); Behavioral: Standard Physiotherapy and Shortwave Diathermy

Study type: Interventional

Funder types: Other

Identifiers

NCT07089459

REC-UOL-/505/08/24

Details and patient eligibility

About

This clinical study aims to explore whether a non-invasive treatment known as Low-Level Laser Therapy (LLLT) can help people with a partial tear of the anterior cruciate ligament (ACL) in their knee. The ACL is one of the major ligaments that helps stabilize the knee joint. When partially torn, it can cause knee pain, weakness, and trouble walking or doing daily activities.

Traditional physiotherapy is often used to treat ACL injuries without surgery. In this study, researchers are testing whether adding LLLT to standard physiotherapy improves outcomes more than physiotherapy alone. LLLT, also called photobiomodulation, is a painless treatment that uses low-energy laser light to reduce swelling and promote tissue healing.

The study includes 72 patients, aged 20 to 40, who have been diagnosed with a partial ACL tear. All participants will receive standard physiotherapy exercises and shortwave diathermy (a type of deep heat therapy). Half of the participants will also receive LLLT, while the other half will not.

The main goals are to see if LLLT can:

Reduce knee pain

Improve knee strength

Help patients perform daily activities more easily

Each participant will be monitored over 6 weeks, with assessments at the beginning, the 3rd week, and the 6th week. Pain levels, muscle strength, and ability to perform daily activities will be measured using standard tools.

Full description

Background & Rationale:

Partial ACL tears are a common orthopedic injury that can cause pain, instability, reduced strength, and functional disability. These injuries are frequently seen in young adults who engage in sports involving pivoting and sudden direction changes. While complete ACL tears often require surgical intervention, partial tears are typically managed conservatively through physiotherapy and other non-surgical interventions.

Low-Level Laser Therapy (LLLT), also known as photobiomodulation, has emerged as a promising treatment to enhance tissue repair, reduce inflammation, and relieve pain. It works by applying low-energy laser light to injured tissue, which stimulates cellular processes and promotes healing. Despite positive results in treating other musculoskeletal conditions, evidence specifically addressing the efficacy of LLLT for partial ACL tears remains limited.

Study Design and Methodology:

This single-blinded, randomized controlled trial includes 72 participants with MRI-confirmed partial ACL tears. Participants are between 20 and 40 years of age, and both genders are included. After screening and consent, eligible participants are randomly assigned to two groups (n=36 each):

Group A (Intervention group): Receives Low-Level Laser Therapy (LLLT) + Standard Physiotherapy + Shortwave Diathermy

Group B (Control group): Receives only Standard Physiotherapy + Shortwave Diathermy

LLLT Parameters:

Wavelength: 830 nm

Power Output: 150 mW

Power Density: 5 W/cm²

Frequency: 2-3 sessions/week for 6 weeks

Probe contact time: 3-4 minutes per site (multiple areas around knee joint)

Standard Therapy (both groups):

Exercises: Heel slides, partial knee bends, quad sets, step-ups

Frequency: 2 sets of 10 reps, rest interval 3-5 seconds

Shortwave Diathermy: 2-3 sessions, 20-30 minutes, 27.12 MHz

Outcome Measures:

Assessments will be done at baseline, 3rd week, and 6th week using the following tools:

Pain: McGill Pain Questionnaire

Strength: Handheld dynamometer for quadriceps/hamstrings

Functional Disability: KOOS (Knee injury and Osteoarthritis Outcome Score)

Blinding & Randomization:

Participants are randomized using computer software

The study is single-blinded; assessors will not know the group assignments

Ethical Considerations:

Approved by the University of Lahore Ethical Committee

Informed written consent obtained

Confidentiality, voluntary participation, and withdrawal rights ensured

Expected Impact:

This study will provide evidence on the clinical value of LLLT as an adjunct to standard rehabilitation for patients with partial ACL tears. It has the potential to guide best practices in conservative management and offer an effective, non-invasive option for improving patient outcomes without surgery.

Enrollment: 72 patients

Sex: All

Ages: 20 to 40 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Pain in knee lasting more than 15 days (Masiero et al., 2020)
• Unilateral partial ACL tear diagnosed with positive lachman test and negative pivot shift test (+ve pivot shift leads to complete tear) with or without other ligament tear (Song et al., 2024)
• No other osteoarticular or soft tissue lesion (Masiero et al., 2020)

Exclusion criteria

• Patients with tumors or other serious diseases (Song et al., 2024)
• History of deep vein thrombosis or vascular pathology in any lower limb (Song et al., 2024)
• Rheumatoid arthritis or other signifcant co-morbidities (Masiero et al., 2020)
• Intraarticular injections into the knee in the preceding 6 months (Song et al., 2024)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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72 participants in 2 patient groups

Low-Level Laser Therapy with Standard Physiotherapy for Partial ACL Tear

Experimental group

Description:

Participants in this arm will receive Low-Level Laser Therapy (LLLT) along with standard physiotherapy exercises and shortwave diathermy. LLLT will be administered 2-3 times per week for 6 weeks using an 830 nm wavelength, 150 mW power output, and 5 W/cm² power density. Standard exercises include heel slides, partial knee bends, quad sets, and step-ups. Shortwave diathermy will be delivered at 27.12 MHz frequency, 20-30 minutes per session. The intervention aims to improve pain, strength, and functional disability in patients with partial ACL tears.

Treatment:

Device: Low-Level Laser Therapy (LLLT)

Standard Physiotherapy Only for Partial ACL Tear

Active Comparator group

Description:

Participants in this arm will receive only standard physiotherapy and shortwave diathermy without Low-Level Laser Therapy. Exercises include heel slides, partial knee bends, quad sets, and step-ups, performed under supervision. Shortwave diathermy will be applied 2-3 times using 27.12 MHz frequency for 20-30 minutes. This arm serves as the control to evaluate the added benefit of LLLT in managing partial ACL tears.

Treatment:

Behavioral: Standard Physiotherapy and Shortwave Diathermy