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: A Study to Investigate the Safety and Effectiveness of Different Doses of Sprifermin in Participants With Osteoarthritis of the Knee

Eligibility criteria:
Inclusion Criteria:

          -  Age from 40 to 85 years; of either sex

          -  Primary femorotibial osteoarthritis according to American College of Rheumatology
             (ACR) clinical and radiographic criteria , and meeting protocol-specified X-ray
             criteria in the target knee at screening

          -  Pain score in the target knee and/or the need for regular symptomatic treatment of
             knee pain with paracetamol (acetaminophen), systemic non-steroidal anti-inflammatory
             drugs (NSAIDs) including cyclooxygenase (COX)-2 selective inhibitors (coxibs), or
             tramadol on most days in the previous month (that is, more than half of the days in
             the previous month)

          -  A history of pain due to Osteoarthritis in the target knee for at least 6 months

          -  A protocol-specified pain score for the target knee in response to Question 1 of the
             WOMAC pain index ("how much pain have you had [in the target knee, over the past 48
             hours] when walking on a flat surface?") after washout of at least 5 half-lives of
             analgesic medication(s): acetaminophen, topical or oral NSAIDS, coxibs, opioids,
             and/or tramadol

          -  Women of childbearing potential must use a form of contraception with a failure rate
             of less than 1 percent per year throughout the trial

        Exclusion Criteria:

          -  Malalignment of greater than 5 degrees in the femorotibial axis of the target knee

          -  Clinical signs of inflammation (redness) in the target knee

          -  Intra-articular administration of corticosteroids or hyaluronic acid into either knee
             within 6 months before Screening

          -  Planned knee surgery (affecting either the target or the contralateral knee) within
             the next two years

          -  Concomitant conditions or treatments deemed to be incompatible with trial
             participation

          -  Any contraindication to MRI according to MRI guidelines, including the inability to
             undergo a knee MRI exam because of inability to fit in the scanner or knee coil

          -  Pregnancy or breastfeeding

          -  Participation in another clinical trial within the 30 days (or 5 half-lives of the
             investigated compound, whichever is longer) before screening

          -  Legal incapacity or limited legal capacity
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): Entailment