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: Efficacy of Intra-Articular Injection of Etanercept for Moderate and Severe Knee Osteoarthritis

Eligibility criteria:
Inclusion Criteria:

          1. Willing and able to give full consent;

          2. According with classification of "Clinical Image" of 1986 American college of
             rheumatology criteria in osteoarthritis of the knee ;

          3. Grade II-III of Kellgren-Lawrence (KL) grading system, revealing synovial inflammation
             or synovial fluid by combining ultrasound and/or MRI

          4. Knee pain for at least 1 Month and Pain VAS Score>4 during the last week;

          5. Fertile women agreed to adopt effective contraceptive measures during the test.

        Exclusion Criteria:

          1. Allergic to pharmaceutical ingredients;

          2. Received Tumor Necrosis Factor inhibitor (TNFI) or other biologics preparation within
             3 months;

          3. Received physical therapy or articular injection, taking antidepressants or
             antispasmodic, opioids within 3 months ;

          4. Patients with history of knee surgery or upcoming surgery within 10 years;

          5. Patients accompanied by other complications or joint disease (such as septic
             arthritis, osteonecrosis,haemochromatosis, ochronosis, etc.);

          6. Patients with serious joint deformation or joint deformities;

          7. Patients with active or a history of recurrent infections;

          8. Patients existing active tuberculosis (TB) or has a history of active TB;

          9. Patients with positive on hepatitis b surface antigen or hepatitis c antibody;

         10. Patients with a history of severe lung disease, tumor;

         11. Patients with severely abnormal function on liver and kidney (liver enzyme > = 2 times
             normal, creatinine > = normal);

         12. Patients with pregnancy, ready for pregnancy or lactation;

         13. Patients with other conditions which not suitable for use of Etanercept.
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.



Eligibility (NLI label): Entailment