This research is designed through randomization, control, and double-blind trial to explore the clinical effectiveness of intravenous laser irradiation of blood for knee degenerative arthritis; and to explore the changes in body's balance function. Furthermore to establish a new way of clinical rehabilitation therapy. The research will further study the special biomarker to investigate the mechanism of low-energy intravenous laser therapy for osteoarthritis.

Background This research is designed through randomization, control, and double-blind trial to explore the clinical effectiveness of intravenous laser irradiation of blood for knee degenerative arthritis; and to explore the changes in body's balance function. Furthermore to establish a new way of clinical rehabilitation therapy. The research will further study the special expression of blood cells after the treatment and as well as the molecular mechanism of low-energy intravenous laser therapy on hematopoietic stem cells. fold of the sun. The light accelerates blood and cells circulation in the human body, so that protein molecular structure would promote changes. Pain control is indicated in such treatment, but still lacking evidence of improving the symptoms of degenerative knee arthritis.

Purpose This research is designed through randomization, control, and double-blind trial to explore the clinical effectiveness of intravenous laser irradiation of blood for knee degenerative arthritis; and to explore the changes in body's balance function. Furthermore to establish a new way of clinical rehabilitation therapy. The research will further study the special biomarker to investigate the mechanism of low-energy intravenous laser therapy for osteoarthritis.

Method The investigators plan to recruit 20 patients who are between the ages of 50 to 75 years old, but younger than 75 years old. The participants are required to have clear conscious and be able to communicate. Their symptoms of degenerative arthritis could be one or both knees which last more than six months; with knee pain greater than 4 points when walking. The treatment group will receive an intravenous helium-neon laser phototherapy. A vein indwelling needle will be placed in their veins located in the upper elbow, and the laser fiber catheter will be introduced through the indwelling cannula. The power is set between 2.5 ~ 3.0Mw, 60 minutes each time, once a day for five consecutive days. The steps for the control group are the same, except that the output power is adjusted to zero intensity. This plan will be explained to the patient in detail during the outpatient visit and patients will sign the consent form upon agreement. Before intravenous laser irradiation, three days, one month, and three months after the therapy, 20 ml of autologous peripheral venous blood need to be drawn for basic blood tests and biomarker tests. At the same time, the clinical functions of patients will be evaluated, including visual analogous scale, Lequesne 's severity index, WOMAC scale, and balance function test.

Inclusion Criteria:

• clear conscious and be able to communicate.
• the symptoms of degenerative arthritis could be one or both knees which last more than six months
• with knee pain greater than 4 points when walking

Exclusion Criteria:

• had ever received intraarticular injection with hyaluronic acid or steroid within 6 months
• had ever received nonsteroidal anti-inflammatory drugs or steroid therapy within 1 week
• neoplasm of joint and peripheral soft tissue
• malignancy
• had ever received total knee arthroplasty or other major surgery
• rheumatoid arthritis
• coagulopathy
• unable to take balance test due to other chronic disease