Effect of High Intensity Laser in Treatment of Myofascial Trigger Points in Symptomatic Knee Osteoarthritis

Effect of High Intensity Laser in Treatment of Myofascial Trigger Points in Symptomatic Knee Osteoarthritis

Effect of High Intensity Laser in Treatment of Myofascial Trigger Points in Symptomatic Knee Osteoarthritis : A Randomized Single-blinded Controlled Trial

This study was conducted to investigate the effect of High intensity laser therapy( HILT) on pressure pain threshold, serum cortisol level, passive knee range of motion, and changes of functional disability in patients with active myofascial trigger points(MTrPs) pain associated wit knee osteoarthritis(OA) .

Osteoarthritis (OA) is the most common cause of musculoskeletal pain and disability. It is a chronic degenerative disorder of multifactorial etiology, including acute and/or chronic insults from normal wear and tear, age, obesity and joint injury. The true pathogenesis remains poorly understood. OA is characterized by a degradation of the articular cartilage, resulting in an alteration of its biomechanical properties, which in turn contributes to a focal loss of articular cartilage, loss of joint space, osteophyte formation, focal areas of synovitis, per articular bone remodeling and sub chondral cysts , OA presents with symptoms such as joint pain, stiffness, motion limitations, motor and sensory dysfunction and functional impairments, thus, preventing patients from participating in regular physical activities , The common sites of OA appear on the knees, hands, and hips, whereas knee OA is the most common . Pain is the most frequent complaint for patients with knee OA to seek medical attention. If left untreated, pain and stiffness can result in a loss of physical function and independence during daily activities. The presence of OA-related knee pain has also been associated with increased risks of physical disability in the community . Many studies have revealed a discrepancy between patients' reports of pain and their radiographic findings , a plausible option is that the pain originates from the myofascial trigger points (MTrPs) in the surrounding muscles (myofascial pain) and cannot be visualized by imaging. The term myofascial pain is defined as "the complex of sensory, motor, and autonomic symptoms caused by MTrPs , MTrPs, hyperirritable spots found in the skeletal muscles, are associated with hypersensitive palpable nodules located in a taut band. The spots are painful on compression and may produce characteristic referred pain, referred tenderness, motor dysfunction, and autonomic phenomena. All studies found a high prevalence of myofascial pain in knee OA patients . study of OA patients, MTrPs were found in all participants, especially in the medial head of the gastrocnemius (92%) and the vastus medialis muscle (67%). The treatment of MPS includes: In activation of trigger points, relaxation of taut bands, and breaking the pain-spasm-ischemia-pain cycle. The most widely used treatment methods for MPS are education, exercise, non steroidal anti-inflammatory drugs (NSAIDs), superficial and deep heat, electrotherapy, laser therapy, and local injections. Laser treatment : Is non- invasive and painless and can be easily administered in therapy units for a wide range of conditions . Recently, high-intensity laser therapy (HILT) was introduced to the field of physical therapy. The advantage of HILT over Low level laser therapy(LLLT) is that HILT is able to reach and stimulate the large and/or deep joints that are difficult to reach in LLLT . The use of HILT has been proven to significantly reduce pain . Previous studies describe the anti-inflammatory, anti-edematous, and analgesic effects of HILT, thus justifying its use in the therapy of pain .

1. Experimental group (A) the laser group (n=20) which received high intensity laser therapy(HILT) knee osteoarthritis conventional exercises program in form of stretching exercises for both vastus medialis and gastrocnemius muscles , ROM exercises for knee flexion and extension , and isometric strengthening exercise of previously mentioned muscles . all interventions were done under the supervision of physiotherapist for 30 minutes once a day for 3 days per week during a period of 4 weeks.

the Sham group (n= 20) which received sham HILT knee osteoarthritis conventional exercises program previously mentioned . all interventions were done under the supervision of physiotherapist for 30 minutes once a day for 3 days per week during a period of 4 weeks.

Zimmer High power laser (with 810 and 980 nm and maximal output power of pmax 7 w cw , made in Germany) with serial number : IEC 60825-1:2007

20 patients received high power laser therapy . Zimmer High power laser applied by laser probe perpendicular to and in slight contact with the skin around knee joint , the total energy was delivered to the patient during one session was 1060 j in 3 phases of treatment.

20 patients received placebo laser " sham laser . The same treatment protocol of HILT was given to the sham group, but the laser instrument was switched off during applications. All laser applications were performed by the same physiotherapist.

knee osteoarthritis conventional exercises program in form of stretching exercises for both vastus medialis and gastrocnemius muscles , ROM exercises for knee flexion and extension , and isometric strengthening exercise of previously mentioned muscles . all interventions were done under the supervision of physiotherapist for 30 minutes once a day for 3 days per week during a period of 4 weeks.

For measuring serum cortisol level, Each patient was drawn two 5 ml blood samples from cubital vein two times.

The first sample was obtained before the first day of treatment and the second sample was obtained after 4 weeks (1 month) of treatment

Pressure pain threshold: The Commander Algometer (JTECH Medical, Midvale, Utah, USA) was used to measure the PPT.

It's a hand-held tool that uses manual pressure to test pain sensitivity in deeper structures. It's a valid tool that's been widely used. The algometer's tip was positioned on the trigger area, and pressure was increased at a rate of 1 kg per second. When the patient expressed discomfort and verified it verbally, the pressure measurement was recorded as kg/cm2, the technique was done three times at 60-second intervals and the average was taken .

The first measure was obtained before the first day's treatment and the second measure was obtained after 4 weeks of treatment (1 month).

Knee Function: knee injury and osteoarthritis outcome score ( KOOS )Score was used to measure the changes of functional disability.

KOOS is a valid, and reliable questionnaire used for assessing the functional status and quality of life (QoL) of patients with any type of knee injuries and osteoarthritis .It assesses five outcomes: pain , symptoms , activities of daily living , sport and recreation function and knee related quality of life . It is a 42-itemself-reported, joint-specific questionnaire which comprises five subscales: Pain (nine items), Symptoms (seven items), Activities of daily life (ADL) (17 items), Function in Sport and Recreation (Sport/Rec) (five items) and Knee-related quality of life (QoL) (four items). Each item is scored from 0 (no problems) to 4 (extreme problems). For each subscale, the score was normalized to a 0-100 scale with higher scores indicating better status.

The first score was taken before the first day's treatment and the second score was taken after 4 weeks of treatment (1 month).

Passive Knee range of motion ( ROM): measured by the digital electronic goniometer Halo device through a standard measuring procedure.

the Electro Goniometer device is considered as standard, simple, portable, valid and reliable device for measuring joints range of motion

The first measure was obtained before the first day's treatment and the second measure was obtained after 4 weeks of treatment (1 month) .

Inclusion Criteria: Patients diagnosed as II degree bilateral knee OA having active MTrP in vastus medialis and medial head of gastrocnemius muscles and over the calf muscle . The patients from both gender aged were ranged from 35 to 55 years. Exclusion Criteria: Reactive synovitis, corticosteroids or hyaluronic acid application during the last six months Not indicated and no history of knee joint arthroplastic surgery. Malignant tumors and chronic infection. Not diagnosed with cushing's syndrome.

data obtained through this study may be provided to qualified researchers with academic interest in myofascial trigger points pain and application of high intensity laser therapy

data requests can be submitted starting 9 months after article publication and the data will be made accessible for up to 2 months.

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