The goal of this clinical trial is to learn if a combination of patient self-administered joint mobilization and exercise works to treat knee osteoarthritis in adults. The main questions it aims to answer are:

• Does self-administered joint mobilization improve the ability to perform regular daily activities?
• Does self-administered joint mobilization improve knee motion?
• Does self-administered joint mobilization improve hip strength?

Researchers will compare the program of self-administered joint mobilization to a joint mobilization administered by a physical therapist.

Participants will:

• Attend 8-12 physical therapy clinic visits over 6 - 8 weeks
• Perform home exercises
• Visit the clinic 6 months later for a brief check-up

This study will take place in the Outpatient Rehabilitation Clinic at Texas Health Resources (THR) in Plano, or in the Texas Health Sports Medicine Clinic in Allen.

Participants in this study will be asked to complete the same intake forms and questionnaires as any other physical therapy patient being seen for knee pain at all of the THR physical therapy clinics. These will include questions about health history, learning style, living situation, and goals for physical therapy treatment. One investigator will perform a physical therapy evaluation, including joint motion, muscle strength, and flexibility measurements, as well as functional testing.

For this study, we will measure one knee motion and one hip strength item and ask participants to complete a knee- specific questionnaire 3 times: on the initial evaluation visit, during the last visit of physical therapy, and during a 6-month follow-up visit.

After the initial evaluation visit, we will assign each participant into one of the two treatment groups, self-joint mobilization or joint mobilization performed by a physical therapist. Participants will be asked to attend 7 - 11 physical therapy treatment visits over 7-8 weeks for strength training exercises, flexibility exercises, joint mobilization, and a home exercise program. Each physical therapy visit, including the initial evaluation visit will last 45 minutes. Participants will be asked to track compliance with a home program and attend a follow-up appointment about 6 months after the initial evaluation. This follow-up visit will last about 30 minutes.

All appointments, except for the 6-month follow-up, will be structured and carried out as they would for any other patient receiving physical therapy for knee pain.

Inclusion Criteria:

• Meets National Institute for Health and care Excellence (NICE) criteria for knee osteoarthritis:
• Age 45 years or older
• Movement-related knee pain
• No morning stiffness or morning stiffness < 30 minutes
• Knee flexion contracture (kFC) at least 1cm, measured by heel-height
• Fluency in verbal and written English for completion of outcome measure and screening, and to take directions.
• Able to attend all study-related appointments

Exclusion Criteria:

• Assistive device required for ambulation
• Systemic disease affecting joint function (diabetes, rheumatological disorders, etc)
• Previous lower extremity joint replacement
• Lower quarter surgery, injection, or therapy in the past year
• Other functionally-limiting physical impairment of the lower quarter
• Spine or lower extremity compensation claim (work, accident, etc)

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