Osteoarthritis (OA) of knee is the most common form of arthritis in the world1e, and it has received growing attention in the society because of the increase of old age population, disabled people, and medical expenses from this disease. 99Tc-MDP is effective for rheumatoid arthritis. Therefore, the investigators try to investigate the effects of 99Tc-MDP treatment in patients with osteoarthritis of knee as compared with celecoxib.

The prevalence of osteoarthritis of the knee (OA) is increasing worldwide and this burden will continue to increase owing to aging of the general population 99Tc-MDP is effective for rheumatoid arthritis. Consequent to an increase in incidence is the rise in the number of patients with knee OA who are prone to further deterioration of the knee. It therefore is important to better understand, control, and attempt to prevent further progression of disease in patients with knee OA. Limitations in walking, stair climbing, and squatting are common patient complaints that greatly interfere with activities of daily living and recreation. Currently there is no definite consensus on the standardized management of OA. Oral analgesic and anti-inflammatory agents are perhaps the most commonly prescribed treatments to alleviate knee OA symptoms. The failure of nonsurgical therapies to modify quality of life in knee OA patients is not surprising given their inability to alleviate physical manifestations of OA. Surgical knee OA interventions generally result in good to excellent patient outcomes. However, there are significant barriers to considering surgery, which limits clinical utility.

99Tc-MDP is actually the decay product of 99mTc-MDP (99mTc-methylene diphosphonate, a US Food and Drug Administration-approved radioactive agent widely used for bone scintigraphy). 99Tc-MDP (Chengdu Yunke Pharmaceutical, Sichuan, China) is a kind of anti-inflammatory drug patented in China (patent no. ZL94113006.1). It was approved for production by the State Food and Drug Administration of China in October 1997. 99Tc-MDP has been demonstrated to be safe and effective in the clinical treatment of immune diseases, such as rheumatoid arthritis (RA), ankylosing spondylitis (AS) and certain bone diseases, such as skeletal metastases from cancer in China. 99Tc-MDP also showed clinical effect on knee OA in our practice. Therefore, the investigators try to investigate the effects of 99Tc-MDP treatment in patients with osteoarthritis of knee as compared with celecoxib.

Inclusion Criteria:

1. Participants with painful osteoarthritis;
2. The standard uptake value (SUV) of OA related knee greater than 10 on 18F- sodium fluoride bone scan;
3. Participants voluntarily participate in the trial, and signed the informed consent.

Exclusion Criteria:

1. Knee joint replacement;
2. Inflammatory arthritis or joint infection of knee;
3. Nervous joint disease;
4. Fracture of joint;
5. Gout arthritis of the knee;
6. Traumatic arthritis.