Effects of Low Level Laser Therapy on Knee Pain and Function in Patients With Knee Osteoarthritis

One of the most common forms of arthritis is Osteoarthritis. Approximately 15% of the population is affected by the disease. The prevalence of the disease increases with the age, with the peak incidence at fourth decade of life. Study shows that in Southern Pakistan mean age of the patients suffering from Osteoarthritis was 58 years. The disease was more dominant in women with the 3:8 male to female ratio. Study shows that 13.9% of adults aged 25 years and above and 33.6% of older adults aged over 65 years are suffering from osteoarthritis.

According to Johnston County Osteoarthritis Project prevalence of symptomatic knee OA was recorded to be 16% and 28% for radiographic knee OA. Kellgren-Lawrence classified knee osteoarthritis based on the appearance of osteophytes in knee AP radiographs. Grades 0-4 were assigned with >2 indicating radiographic OA. Pain and stiffness are significant clinical features of OA which leads to reduced physical function while articular cartilage degeneration is considered to be important pathological feature of OA. Genetic factors, age-related physiological changes and biomechanical factors are considered risk factors of osteoarthritis. Several studies shows that increased age and BMI increases the risk of knee osteoarthritis. One of the important factors in knee osteoarthritis is being overweight.Physical inactivity is also associated with osteoarthritis. Most notable symptom of osteoarthritis is pain which is also determining factor of disability in patients with osteoarthritis. Pain increases physical inactivity which leads to increased body weight and eventually predispose the person to osteoarthritis.Quadriceps weakness may contribute to prompt clinical finding of knee osteoarthritis. Pain of osteoarthritis may causes reduced quadriceps strength. However some studies reveal that quadriceps weakness plays as a risk factor for knee osteoarthritis especially in females. Reduced muscle strength was reported in 24% of patients with Kellgren-Lawrence grade II knee OA. It is widely accepted that among the patients with knee osteoarthritis quadriceps weakness is caused by muscle atrophy which reduces muscle strength. It is reported that age-related quadriceps weakness is linked with functional limitations and increased rate of falling among elders.

Treatment options for osteoarthritis include pharmacological and non-pharmacological methods. The primary goal of these treatments is to relieve joint pain and improve functional quality of life. Non-steroidal anti inflammatory (NSAIDS) are used widely but their use is now limited due

to high frequency of side effects specially side effects of gastrointestinal tracts.Therefore non-pharmacological treatment is preferred for elderly patients. Non-pharmacological treatment includes weight reduction, manual therapy, strengthening exercises, electrical stimulation, ultrasound, interferential current and laser therapy.

Low level laser therapy (LLLT) is non-invasive and painless modality used for the treatment of knee osteoarthritis. Studies show that it markedly alleviates both acute and chronic conditions such as carpal tunnel syndrome, knee injuries, low back pain, chronic arthritis and rheumatoid arthritis. Due to its stimulatory effect on tissue metabolism and ability to regulate the inflammatory effect after knee injuries, LLLT is considered as a favorable therapeutic modality for OA. It is reported that LLLT was effective for fibroblast and osteoblast proliferation, bone regeneration, collagen synthesis, cellular oxygenation and release of neurotransmitters linked with pain modulation.