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: Methotrexate in the Treatment of Advanced Knee Osteoarthritis With Effusion-synovitis

Eligibility criteria:
Inclusion Criteria:

          -  Meet the America College of Rheumatology (ACR) criteria for clinical knee OA assessed
             by a rheumatologist

          -  Knee pain, visual analogue scale (VAS) pain at least 40mm

          -  Kellgren-Lawrence(K-L) grade of 2-4

          -  Physical examination showed signs of inflammation (at least 2 of the following 4
             clinical signs of inflammation: warmth around the joint; tenderness around joint
             margin; articular cavity effusion; swelling of soft tissue around the knee joint)

          -  MRI evaluated effusion synovitis grade of ≥ 2

          -  Capable of understanding the study requirements and willing to cooperate with study
             instructions, and voluntarily sign informed consent

        Exclusion Criteria:

          -  Inflammatory arthritis (such as gout, reactive arthritis, rheumatoid arthritis,
             psoriatic arthritis, seronegative spondyloarthropathy), systemic lupus erythematosus

          -  Knee surgery or arthroscopic examinations were performed or planned within one year,
             Severe valgus knee deformity (angle of genu valgum > 30°) or previous traumatic
             history

          -  MRI contraindications

          -  Intra-articular injection, intramuscular injection or oral glucocorticoid were used
             within the last 4 weeks

          -  Other anti-synovitis agents (such as hydroxychloroquine and sulfasalazine) were
             applied in the past 3 months

          -  Clinical significant conditions, such as (but not limited to) active malignant tumor,
             abnormal renal function (assessed by GFR), hepatic abnormalities [active hepatitis B,
             hepatitis C, abnormal liver function (ALT is more than twice the upper limit)],
             respiratory diseases (lung infection, pulmonary fibrosis), hematological changes (e.g
             white blood cell (WBC) count < 4 x 10^9 /L, platelet < 100 x 10^9 /L or hemoglobin <
             100 g/L), serious diseases of gastrointestinal, endocrine, heart, nerve or brain
             assessed by clinical physicians

          -  Infectious history such as HIV infection

          -  Hypersensitivity to methotrexate

          -  Pregnant and Lactating women
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 45 Years old.
Subject must be at most 70 Years

Eligibility (NLI label): Entailment