Low-level Laser Therapy and Static Stretching in Knee Osteoarthritis.

Osteoarthritis (OA) is a highly prevalent and disabling disease. It is estimated that by 2030 the prevalence of symptomatic OA could reach 30% of the population above 60 years. It is associated with significant morbidity being one of the most common causes of joint pain, functional disability and compromised quality of life. This randomised controlled trial will investigate the effect of low-level laser therapy (LLLT) and static stretching exercises, as monotherapy and in combination, on pain, quality of life, function, mobility, knee range of motion (KROM) and hamstring length in participants with knee OA.

This study will involve 145 people aged 50-75 years with symptomatic radiographic knee OA and will consist of two types of treatments: Low-level laser therapy (LLLT) and stretching exercises. The patients will be randomly allocated to five study groups LLLT active+Stretch, LLLT placebo+Stretch, Stretch, LLLT and Control (with n=29 each). Treatment frequency will be three sessions/week for all active groups. LLLT will involve the use of a Galium-Arsenide laser (904nm, 40 milliwatts, 3 Joules/point, 27 Joules/knee) over 24 sessions for the monotherapy group and 9 sessions for the LLLT+Stretch groups. Stretching will consist of seven exercises completed over 24 sessions. The control group will receive a booklet.

The primary outcome is pain measured by Visual Analogue Scale. Secondary outcomes included quality of life assessed by Western Ontario and McMaster Universities Arthritis Index (WOMAC), function by Lequesne Algofunctional Index, mobility by Timed Up and Go Test (TUG), KROM by goniometry of knee flexion and hamstring shortening by popliteal angle. The statistical method will follow the principles of per-protocol analysis.

Physical performance as a determinant of disability in osteoarthritis (OA) has been investigated extensively, but research has focused primarily on the effect that the decrease in muscle strength has on the functionality in patients with OA. However, the reduced range of motion in affected joints is also an important risk factor for the occurrence of locomotor disability and other developing disability in patients with OA.

Studies using stretching exercises are scarce in the Reid \& Mc Nair (2010) specifically examined the range of motion can be improved in subjects with knee osteoarthritis, although this study did only stretching the hamstrings. The results indicate that there is immediate benefits of stretching in subjects with osteoarthritis of the knee joint, providing evidence for the long term development of stretching programs for this population.

In the literature are observed inconsistent results regarding the benefits of laser treatment in improving pain and function in individuals with knee OA. Also there are few studies that specify which dosage and frequency of laser must be used.

In view of the increasing need to support the role of physiotherapy in evidence-based practice, this study is justified by the need to test the effectiveness of stretching exercises and elucidate the effectiveness of low intensity laser therapy in patients with knee OA.

Eligibility Criteria:
Inclusion Criteria:

* radiographic evidence of knee osteoarthritis between 2-4 in Kellgren \& Lawrence classification
* pain intensity ≥3 on a 10cm Visual Analogue Scale (VAS)
* knee symptoms for at least 3 months

Exclusion Criteria:

* symptomatic hip osteoarthritis
* any disease where laser treatment is contraindicated (cancer and uncontrolled diabetes mellitus)
* continuous use of anti-inflammatory drugs
* other concurrent injury/conditions that will affect their ability to participate in the rehabilitation program and/or assessment procedures.