Patient case (clinical description): A 47-year-old woman comes to the office complaining of pain in the calf and knee when she bends down. The pain limits her activity. Her medical history is significant for osteoarthritis, for which she uses nonsteroidal anti-inflammatory drugs (NSAIDs) for the past two years. She is living with her husband and has 3 children. She doesn't smoke but drinks alcohol occasionally. Her vital signs are normal. On physical examination, there is a small effusion in the right knee. The effusion grew a little larger and she developed a tender swelling in the popliteal fossa and calf. Both the pain and swelling worsened as she bent and straightened her knee.

Patient's own account: I'm a 47-year-old woman, married with 3 kids. I don't smoke and I drink occasionally. I went to the doctor because of pain in my calf and knee when I was bending down. This has been limiting my daily activities. I have been diagnosed with osteoarthritis for which I have taken anti-inflammatory drugs for the past 2 years. The doctor saw a small fluid buildup in my right knee. This buildup became a bit bigger and I have a swollen calf. The pain is worse when I bend and straighten my knee.

Clinical trial: Evaluation of the Efficacy of a Home-Use Photobiomodulation Device for the Treatment of Patients With Knee Osteoarthritis: A Prospective Double Blind, Randomized, Sham-Controlled Clinical Study

Eligibility criteria:
Inclusion Criteria:

          -  Diagnoses of knee osteoarthritis:( American College of Rheumatology (ACR) criteria
             (see below) - possibilities:ACR1: Fulfilled at least one of the classification
             criteria of the American College of Rheumatology ACR2: KOA verified with the American
             College of Rheumatology criteria using a history and physical examination, i.e. knee
             pain and at least three of the following: 50-85 years old, ≤ 30 minutes of morning
             stiffness, crepitus on active range of motion, bony tenderness, bony enlargement, and
             no palpable warmth of synovia Radiographic evidence of knee osteoarthritis between 2-3
             in Kellgren and Lawrence classification

          -  KOA grade 2-3

          -  Knee pain on movement 40 to 90 mm Visual Analog Scale

          -  Knee pain for the last ≥ 3 months

          -  Functional reduction in the last three months

          -  Agrees not to use NSAIDs throughout the experiment

          -  Agrees not to use any other treatment (except rescue drugs) for KOA during
             participation in this study.

        Exclusion Criteria:

          -  Other causes of knee-related pain (e.g. hip OA, arterial insufficiency, etc) have been
             ruled out by physical examinations

          -  Knee surgery for KOA

          -  Intra-articular steroid injection and/or oral steroid treatment within the last six
             months

          -  Rheumatoid arthritis;

          -  Symptomatic OA in other joints (i.e. hip, hand)

          -  Use of analgesics on the day of evaluation

          -  Use of NSAIDs 2 weeks before the beginning of the treatment

          -  Active malignancy

          -  Uncontrolled diabetes mellitus

          -  Neurological conditions: sciatica, neuropathy, multiple sclerosis

          -  Other chronic pain conditions: Fibromyalgia, back pain, hip pain

          -  Enrolled in any other clinical trial within the last 6 weeks or enrollment in another
             clinical trial during participation in this trial.
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 50 Years old.
Subject must be at most 85 Years

Eligibility (NLI label): Contradiction