Low Level Laser Therapy in 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.

Evidence shows that regular physical activity reduces pain and improves physical function among the patients with knee OA. However being inactive and disuse of affected limb may disturbs joint mechanics leading to softening of articular cartilage which leads to rapid degeneration of cartilage. This study will focus on additive effects of LLL therapy on knee OA patients for improving pain and function. This study will provide an insight in traditional methods that are used in OA patients.

1. LITERATURE REVIEW: Osteoarthritis is the most common form arthritis which is overall ranked among 50 common sequelae of injuries and diseases. Almost 250 million people or 4% of the world's population is affected by osteoarthritis. It is generally divided into primary OA and secondary OA. Etiology of primary OA is not clear but some factors such as genetic factor, ethnicity, age related changes and biomechanical factors play an important role. Post traumatic, dysplastic, infectious, inflammatory or biomechanical etiologies are common cause of secondary OA.

Females are more affected with hand, feet and knee OA. Women are more subjected to severe knee OA than men especially after menopause due to the role of estrogen. Oestrogen unmasks the symptoms of OA by increasing pain sensitivity(1). According to a study male to female ratio affected by OA in Pakistan is 3:8.

Most significant symptom of knee OA is pain leading to increased physical inactivity which increases body weight and predispose the person to OA. Obesity is also a risk factor for developing knee OA.

Pain in knee OA also reduces strength in quadriceps muscle. Quadriceps weakness in OA may be associated with the action of quadriceps during gait. Shock absorption at the knee is provided by eccentric contraction of quadriceps. The spontaneous loading at the knee resulting from inability to compensate the large compressive forces leads to quadriceps weakness and osteoarthritic changes.

A number of evidence shows that exercise reduces the symptoms of OA and improves the knee joint function. However the most advantageous type or combination of exercises is uncertain. Physical inactivity and disuse of the affected limb result in loss of flexibility around knee joint leading to impaired joint mechanics and increased clinical findings of pain. Participation in physical activity and exercise has been recorded to improve joint function and beneficial for the treatment of knee OA.

Physical therapy interventions for knee OA include electrical stimulation, manual therapy, strengthening exercises, ultrasound, interferential current therapy, laser therapy and orthotic devices. Low level laser therapy (LLLT) has been widely used for relieving pain in many

musculoskeletal disorders. It has been considered as non-invasive and safe treatment for knee OA due its stimulatory effect on tissue metabolism and ability to regulate inflammatory process after injury Osteoarthritis is more common in females as compared to males. Pain, joint stiffness and reduced physical activity are prominent symptoms of knee OA. Genetic factors, reduced BMI, overweight, age related physical changes and quadriceps weakness are considered risk factors for knee OA. Physical inactivity disturbs the knee biomechanics and increases the symptoms of knee OA. Studies show that exercise helps to improve the symptoms of knee OA and enhance physical function. Low level laser therapy is non-invasive and painless therapeutic modality used for treating knee OA. Evidence proves that LLLT helps in relieving pain of OA and improving microcirculation due to its stimulatory effect on tissue metabolism.