Effect of High Intensity Laser Therapy on Pain and Function in Patients with Medial Meniscal Injury of Knee - An Experimental Study

Title : Effect of High Intensity Laser Therapy on Pain and Function in Patients with Medial Meniscal Injury of Knee - An Experimental Study

The meniscus is a critical fibrocartilaginous structure within the knee joint, with the medial meniscus forming a C-shaped wedge that covers approximately 50-60% of the medial tibial plateau. Its primary biomechanical functions include shock absorption, load transmission between the femur and tibia, enhancement of joint congruency and stability, and joint lubrication. The medial meniscus is firmly attached to the deep fibers of the medial collateral ligament and the joint capsule, which limits its mobility and renders it more susceptible to injury compared to the more mobile lateral meniscus.

Meniscal tears are among the most common orthopedic injuries, affecting a wide demographic. They can occur from acute trauma, typically involving rotational or shearing forces on a flexed, weight-bearing knee, or from degenerative changes that weaken the meniscal tissue over time. The proposal cites a notable incidence of 222 MRI-confirmed meniscal tears per 100,000 people in symptomatic knees. Clinical presentation commonly includes localized joint line pain, effusion (swelling), stiffness, and mechanical symptoms such as a popping sensation at the time of injury, catching, or locking of the knee joint.

The proposed intervention, HILT, is an emerging electrotherapeutic modality that is distinct from the more established Low-Level Laser Therapy (LLLT). HILT utilizes laser beams with a power output greater than 500 mW, allowing for deeper tissue penetration and the rapid delivery of a substantial amount of energy to the target pathology. The therapeutic rationale for HILT is based on its ability to induce photothermal, photochemical, and photomechanical effects at the cellular level. These effects are proposed to stimulate biological processes conducive to healing, including increased cellular metabolism and adenosine triphosphate (ATP) production, enhanced local blood circulation, and modulation of inflammatory mediators. The ultimate clinical goals are analgesia, reduced inflammation, and accelerated tissue repair.

The study is designed as a pre-post experimental trial to be conducted within outpatient physiotherapy departments in Surat, India. The target population consists of male and female patients aged 18 to 40 years with a recent MRI confirming a Grade 1 or Grade 2 traumatic medial meniscal injury. Participants will be randomly allocated to one of two groups. The control group (Group B) will receive a conventional treatment protocol comprising Interferential Current (IFC) therapy and a structured program of therapeutic exercises. The experimental group (Group A) will receive the identical conventional protocol with the addition of HILT.

The primary outcomes for the study are pain intensity and knee function. Pain will be quantified using the Numeric Pain Rating Scale (NPRS), a well-validated tool for assessing subjective pain levels. Knee function will be evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS), a comprehensive, patient-reported outcome measure. Notably, the protocol includes the use of the validated Gujarati version of this instrument (KOOS-G) to ensure cultural and linguistic appropriateness for the local population.

The patient will be screened on the basis of inclusion and exclusion criteria and their demographic data will be taken by an assessment Performa. Prior to the Commencement of the study, detailed procedure of the study will be explained to the Patients and a signed informed consent form will be taken from them. Then the Patient will be randomly assigned to a 4-week intervention protocol and allocated randomly to Group A and Group B. The subjects will be allocated to any of the two groups by random allocation using chit method. The therapist will measure pain, Functionality before the intervention on the first day of the Treatment.