The purpose of this study is to assess the ability of long-duration low-intensity therapeutic ultrasound (LITUS) to alleviate knee Osteoarthritis pain over an 8-week period. The primary objective of this study is to evaluate the analgesic effect of LITUS in subjects suffering from knee Osteoarthritis pain. Secondary objectives are to assess the ability of LITUS to improve joint function.

This is an 8-week study to clinically evaluate the effectiveness of the Sustained Acoustic Medicine (SAM) device combined with diclofenac on symptoms of patients suffering from knee osteoarthritis. The class-II device, sam®, has been FDA-cleared for home use. On the first day of the study, baseline data will be collected as patients report pain score before treatment. During the following 8 weeks, patients will self-apply their assigned treatment for the 4 hours daily. Each day of the study, pain scores will be recorded immediately before application of SAM device as well as at the completion of treatment. A quality of life and function assessment will be performed prior to the patient beginning the protocol and at the conclusion of the protocol.

Over 120 subjects will be recruited from neighboring communities to the study sites. The study is designed to reach a target patient population which includes rural citizens and socioeconomic disadvantaged individuals.

Inclusion Criteria:

• Have physician-diagnosed mild to moderate knee OA (OARSI atlas grades 1-2)
• Fulfill the American College of Rheumatology clinical and radiological diagnostic criteria for knee OA
• Are between 35-80 years of age
• Report a frequent pain score between 3-7 (range: 0-10) during the week preceding enrollment
• Report that knee pain negatively affects quality of life
• Are willing not to use any cream, gel, or topical solution during the administration of treatment other than the approved treatment provided to the subject at the initiation of the study
• Are deemed appropriate by their physician or by the study site physician to participate.
• Be willing and able to self-administer treatment daily within their place of residence or during normal daily activity, excluding bathing, showering, or other water activities which may result in submersion of the study device.
• Not use or initiate opioid and/or non-opioid analgesic medications.
• Be willing to discontinue any other interventional treatment modalities on the knee during the study period (e.g., transcutaneous electrical nerve stimulation, electronic muscle stimulation, traditional ultrasound).

Exclusion Criteria:

• Cannot successfully demonstrate the ability to put on and take off the device.
• Displays any condition which, in the judgment of the investigator, would make participation in the study unacceptable including, but not limited to, the subject's ability to understand and follow instructions.
• Participated in a clinical trial for an investigational drug and/or agent within 30 days prior to screening.
• Is pregnant.
• Is a prisoner.
• Is non-ambulatory (unable to walk).
• Has a pacemaker.
• Has a malignancy in the treatment area.
• Has an active infection, open sores, or wounds in the treatment area.
• Has impaired sensation in the treatment area, such as caused by chemotherapy or anesthesia.
• Has a known neuropathy (disease of the brain or spinal nerves).
• Has a hereditary disposition (tendency) for excessive bleeding (hemorrhage).
• Have knee replacement, other surgical intervention, or hyaluronidase injection in the affected knee in the past 6 months
• Are currently taking steroids
• Have a secondary cause of arthritis (metabolic or inflammatory)