Terminated early for poor study design.

The primary objective of this study is to determine the levels of proteins and/or cellular components of the synovial fluid that are indicative of microenvironment phenotypes of the osteoarthritic knee compared to unilateral unaffected joints pre-injection to 6 weeks post-Regenexx® SD treatment.

The primary objective of this study is to determine the levels of proteins and/or cellular components of the synovial fluid that are indicative of microenvironment phenotypes of the osteoarthritic knee compared to unilateral unaffected joints pre-injection to 6 weeks post-Regenexx SD treatment (day 0).

Secondary objective is an evaluation of possible direct and/or indirect associations between the measured levels of proteins and/or cellular components of the synovial fluid in the osteoarthritic knee joint with the administration of the Regenexx SD treatment. The secondary objective will include MRI evidence of cartilage repair; incidence of post-operative complications, adverse events, re-injections, and surgical intervention; change in pain score and use of pain medications.

Inclusion Criteria:

1. Voluntary signature of the IRB approved Informed Consent
2. Unilateral osteoarthritic male or female ages 35-85
3. Pain, swelling, and/or functional disability in the affected knee consistent with osteoarthritis in one knee joint
4. Physical examination consistent with osteoarthritis in one knee joint
5. Restricted range of motion of the affected knee (<135 degrees in flexion and/or >0 degrees of extension)
6. Kellgren-Lawrence grade 2 or greater knee osteoarthritis with diagnostic MR imaging of the affected knee showing osteoarthritis
7. Limited knee effusion in osteoarthritic knee (i.e. not more than 20 ml of visible joint fluid on ultrasound examination of the knee.)
8. Normal range of motion of the unaffected knee
9. No sign of pain, swelling, and/or functional disability of the unaffected knee
10. No history of acute injury in the unaffected knee
11. Is independent, ambulatory, and can comply with all post-operative evaluations and visits

Exclusion Criteria:

1. Knee injections of any type within 6 months prior to the study.
2. Inflammatory or auto-immune based joint diseases or other lower extremity pathology (e.g., rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, polymyalgia, polymyositis, gout pseudogout)
3. Quinolone or Statin induced myopathy/tendinopathy
4. Symptomatic lumbar spine pathology (e.g. radicular pain)
5. Severe neurogenic inflammation of the cutaneous nerves about the knee or thigh (i.e. evidence of complex regional pain syndrome or central sensitization with allodynia present on exam).
6. Contraindications for MRI
7. Tested positive or has been treated for a malignancy in the past five years or is suspected of having a malignancy or is currently undergoing radiation or chemotherapy treatment for a malignancy anywhere in the body, whether adjacent to or distant from the proposed injection site
8. Condition represents a worker's compensation case
9. Currently involved in a health-related litigation procedure
10. Is pregnant
11. Bleeding disorders
12. Currently taking anticoagulant or immunosuppressive medication
13. Allergy or intolerance to study medication
14. Use of chronic opioid
15. Documented history of drug abuse within six months of treatment

18) Any other condition, that in the opinion of the investigator, that would preclude the patient from enrollment

Subjects will have unilateral knee OA as evidenced with physical examination and MRI. Subjects will be recruited from the physician practice and will be males and females age 35-85.