A new generation of "minimally manipulated" regenerative treatments are being offered at clinics across the country, but there is no strong efficacy data to support their use. The purpose of this study is to estimate the effect size of the treatment by comparing the efficacy of autologous fat to the current standard of care treatment, hyaluronic acid (HA). As a secondary aim, we will test for preliminary evidence of efficacy of autologous fat vs. HA and determine how these treatments effect the biochemical environment of the knee by comparing pre-injection and post-injection synovial fluid biomarker profiles.

In recent years, fat treatments administered for structural reconstruction, repair, or replacement are being increasingly offered at clinics across the country. These treatments contain both autologous cells that are often referred to as "stem cells" or "MSCs" and extra-cellular matrix (ECM). Cell therapies containing ECM are thought to have the following advantages over treatments prepared using enzymatic digestion: (1) preservation of the stromal vascular niche, which allows time-release of the regenerative factors; (2) release of bioactive molecules by exosomes, which have been demonstrated to be significantly greater in mechanically processed fat than enzymatically processed fat; and (3) maintenance of the structural and morphologic unit, which is thought to increase cell efficacy by making the cells more resilient to the harsh conditions in the recipient environment. Case reports investigating the use of autologous fat treatments show promise, but a number of questions remain unanswered. Agents injected into the joint tend to be quickly cleared from the body and ECM itself has the potential to produce inflammatory signals and induce osteoarthritis.

This study will use a Hyaluronic acid (HA) as an active control, which is the standard of care for pain associated with osteoarthritis. The use of HA as an active control for autologous cell-based therapies is well established and is the best option given the need to aspirate fat tissue from patients who will be receiving the study treatment.

Inclusion Criteria:

1. Age 45 to 75, inclusive
2. Normal axial alignment
3. X-ray, Kellgren-Lawrence OA grade 2 - 3, inclusive
4. WOMAC-pain: Between 9 and 19, inclusive
5. Willingness to participate all scheduled follow-ups
6. Willingness to refrain from taking NSAIDs, level 2 analgesics, and opioids for the course of the study
7. BMI < 40

Exclusion Criteria:

1. Pregnant or lactating
2. Intra-articular injection within 3 months of treatment
3. Inflammatory arthritis
4. Any disease or active drug use that significantly compromises coagulation
5. Significant damage and/or tears of the ACL or other supporting tissues
6. Prior knee surgery in the last 6 months in the knee that will be injected
7. Active tobacco use
8. Active alcohol or substance abuse within 6 months of study entry
9. Known hypersensitivity (allergy) to hyaluronan (sodium hyaluronate) preparations
10. Knee joint infections, skin diseases or infections in the area of the injection site
11. Diabetes
12. Active inhaler use
13. Any medical condition, which in the opinion of the clinical investigator, would interfere with the treatment or outcome evaluation

Patients will know which group they have been assigned to