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: Pilot Study of Therapy With Hylan G-F 20 Exercise Capacity

Eligibility criteria:
Inclusion Criteria:

          -  Male and female individuals aged between 40 and 70 meeting the American College of
             Rheumatology (ACR) criteria for primary knee OA with radiographic and symptomatic
             evidence of TF OA for ≥6 months.

          -  Radiographic osteoarthritis Kellgren-Lawrence Grade II-III (radiographs taken at
             entry) in affected knee.

          -  Average pain numeric rating (defined as moderate level) of 4 - 8 on a scale of zero to
             10 over the past week.

          -  No previous viscosupplement therapy in any joint in past 12 months at the time of
             randomization.

          -  No intra-articular steroids in the past 6 months.

          -  Currently sedentary per American College of Sports Medicine (ACSM) criteria (MET level
             <9) and at least one of the following cardiovascular risk factors:

          -  Obesity (BMI between 30 and 40)

          -  Diabetes mellitus

          -  HTN (JNC guidelines for HTN stage 1: Systolic >/=140 and diastolic >/= 90)

          -  Dyslipidemia (ATP3 Guidelines for dyslipidemia: LDL>160, total cholesterol >/=240 and
             HDL<40)

          -  Established CAD per clinical or imaging diagnosis

          -  Allowed medications include stable prescription dose of NSAIDS and/or tramadol. Ad lib
             use of OTC analgesics will be allowed in both groups.

        Exclusion Criteria:

          -  Grade I and IV OA.

          -  History of viscosupplementation in any joint in the past 12 months at the time of
             baseline visit.

          -  Isolated patello-femoral OA or isolated anterior knee pain (patello-femoral OA
             co-existing with tibia femoral KOA may be included).

          -  Symptomatic bilateral knee OA (unless the contra-lateral knee involvement is limited
             to radiographic OA and not symptomatic).

          -  Ipsi-lateral symptomatic OA of hip or ankle; contra-lateral symptomatic OA of hip,
             knee, or ankle, or clinical evidence of hip disease.

          -  Clinically apparent tense effusion or other acute inflammation of the target knee at
             baseline.

          -  History of:

               -  Septic OA of any joint

               -  Inflammatory arthropathy such as rheumatoid arthritis, gout, pseudogout, lupus,
                  crystalline arthropathy, chondrocalcinosis and other rheumatology diagnosis in
                  judgment of the investigator.

          -  Active infection of lower extremity (e.g., cellulitis).

          -  Prosthetic implant in hip and/or lower extremities.

          -  Any clinical indication for arthroscopic surgery at the time of enrollment.

          -  Planned surgeries during the trial period (e.g., scheduled/awaiting for arthroscopy or
             a knee replacement procedure for OA of the knee).

          -  Plans to initiate other OA treatments including, but not limited to non-pharmacologic,
             pharmacologic, surgical, chiropractic, acupuncture, yoga, Tai chi, physical therapy
             during the study period

          -  Any other intra-articular knee joint injection during the study.

          -  History of systemic and/or intra-articular steroid injection in target knee within six
             months of baseline visit.

          -  History of arthroscopic surgery in affected knee in past 12 months at baseline visit.

          -  Cruciate/collateral knee ligament instability, ligament laxity, or meniscal
             instability of target knee.

          -  Significant alignment deformity such as varus/valgus of target knee in the judgment of
             the investigator.

          -  Venous or lymphatic stasis in either leg.

          -  Peripheral vascular disease.

          -  Concurrent multi-system or multi-limb trauma.

          -  Pregnancy or mothers who are breastfeeding. Urine pregnancy test will be administered
             at baseline for women of childbearing potential.

          -  On chronic opioid analgesic therapy that cannot be altered. Chronic is defined as ≥6
             months.

          -  Known contraindication to acetaminophen.

          -  Currently enrolled in another clinical trial or history of trial enrollment within
             three months at baseline.

          -  Plans to move/relocate significantly out of area during study period.

          -  Workman's Compensation beneficiary at base line visit.

          -  The presence of secondary diagnosis such as neuropathy (any type), radiculopathy, or
             other nervous system conditions in the judgment of the investigator, contributing to
             other lower extremity pain that limits activity.

          -  Physical Therapy for OA of the lower extremity within 6 months prior to enrollment
             into the study.

          -  Any musculoskeletal condition besides OA of the knee that limits exercise or normal
             daily function.

          -  Acute coronary conditions that are deemed inappropriate for participating in an
             exercise program.

          -  Pulmonary conditions limiting functional capacity.

          -  Known allergy to hylan G-F 20 or any, of its components, or to avian proteins, eggs,
             feathers, down or poultry.
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 70 Years

Eligibility (NLI label): Contradiction