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: Effect of Hip and Core Muscle Strengthening for Patellofemoral Osteoarthritis: A Feasibility Study

Eligibility criteria:
Inclusion Criteria:

        Patellofemoral Osteoarthritis group: 1) age 35-70 years, 2) have been diagnosed with knee
        osteoarthritis in one or both knees with symptoms primarily in the anterior knee, 3)
        radiographic evidence of ≥ Grade 1 osteophytes or joint space narrowing at the
        patellofemoral joint according to the Osteoarthritis Research Society International (OARSI)
        grading scale (0 = none, 1 = mild/possible, 2 = moderate/definite, 3 = severe), 4) pain
        produced by ≥ 2 of the following: descending steps, ascending steps, sit-to-stand,
        squatting, kneeling, prolonged knee flexion, increased activity (e.g., hiking), morning
        stiffness < 30 minutes, stiffness after sitting ≥ 30 minutes, history of patellar
        subluxation or dislocation in the past.

        Control group: 1) age 35-70 years, 2) no known diagnosis by a physician of knee
        osteoarthritis, 3) pain free in the lower extremities at the time of enrollment into the
        study and for 1 week prior to enrollment.

        Exclusion Criteria:

        Patellofemoral Osteoarthritis (PFOA) group: 1) the presence of other conditions that may
        cause knee pain (e.g., patellar tendonitis, rheumatoid arthritis), 2) neurologic or
        musculoskeletal conditions that may alter lower extremity kinematics (e.g., multiple
        sclerosis, hip arthritis/arthroplasty), 3) history of a fracture of the knee, 4) pregnancy,
        5) knee injections within the past 3 months, 6) inability to understand English.

        Control group: 1) all previously listed exclusion criteria for the PFOA group, 2) knee pain
        produced by 2 or more of the following: descending steps, ascending steps, sit-to-stand,
        squatting, kneeling, prolonged knee flexion, or a history of patellar subluxation or
        dislocation in the past.
No condition on gender to be admitted to the trial.
Accepts Healthy Volunteers
Subject must be at least 35 Years old.
Subject must be at most 70 Years

Eligibility (NLI label): Entailment