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: Different Volumes of Durolane in Knee OA

Eligibility criteria:
Inclusion Criteria:

          -  Subject (female or male)

          -  40-85 years of age

          -  Unilateral knee pain fulfilling American College of Rheumatology (ACR) criteria for
             diagnosis of osteoarthritis(OA)

          -  Radiographic evidence of OA in the study knee

          -  WOMAC pain score of 7-17 in the study knee

          -  WOMAC pain score of 2-3 in the study knee (WOMAC Likert 3.1 A1)

          -  Subject normally active

          -  Subject has attempted but not responded adequately to previous non-pharmacological
             therapy(ies)and to simple analgetics

          -  Subject cooperative and able to communicate effectively with the investigators

          -  Body mass index ≤ 35 kg/m2;

          -  Signed informed consent obtained

        Exclusion Criteria:

          -  Knee effusion

          -  Contralateral knee OA

          -  Clinically significant joint pain from joints other than the knee

          -  Previous intra-articular steroid injection into the study knee within the last 6
             months

          -  Previous intra-articular Hyaluronic Acid (HA) injection into the study knee within the
             last 9 months

          -  Previous allergic type reaction to a HA product

          -  Treatment with analgesics other than paracetamol (acetaminophen) (including topical
             agents for the knee) within 5 half lives of the drug prior to the baseline visit

          -  Use of analgesics 48 hours preceding the baseline visit

          -  Use of systemic glucocorticosteroids (excluding inhaled steroids) within the last 3
             months

          -  Treatment with glucosamine/chondroitin sulfate initiated within the past 3 months

          -  Change in physical therapy for the knee within the last three months

          -  Arthroscopy or other surgical procedure in the study knee within the past 12 months

          -  Serious injuries to the study knee in the past

          -  Any planned arthroscopy or other surgical procedure during the study period

          -  Previous history or presence of active septic arthritis

          -  Active skin disease or infection in the area of the injection site

          -  Systemic active inflammatory condition or infection

          -  Bleeding diathesis or use of anticoagulants

          -  History of drug or alcohol abuse within 6 months

          -  Any medical condition that in the opinion of the investigator makes the subject
             unsuitable for inclusion

          -  Pregnant or breastfeeding woman or woman of childbearing potential not practicing
             adequate contraception

          -  Involvement in other clinical trials
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 40 Years old.
Subject must be at most 85 Years

Eligibility (NLI label): Contradiction