Knee osteoarthritis (OA) is a leading cause of disability. The objectives of treatment are to reduce pain, improve function, and slow down further breakdown of the knee. Recently, research on nonsurgical treatment options for knee OA has increased significantly. One potential treatment of interest is the use of stem cell injections. Stem cells are one's own cells that have the ability to divide into other types of cells, and may cause regrowth of cartilage when injected into the knee. There have been few, but promising, studies that show improvements in pain and function with stem cell injections in those with knee OA. Therefore, more research is needed to identify patients who might benefit from this injection. This pilot study will look at changes in pain and function for 20 patients at 1, 3, 6, and 12 months after a stem cell injection into the knee. Patients will also undergo magnetic resonance imaging at 6 months and 12 months following the injection.

Inclusion Criteria:

• >=3 months of symptomatic knee OA unresponsive to at least two of the following: activity modification, physical therapy, bracing, assistive devices, acupuncture, non-steroidal anti-inflammatory medications, local steroid injections, and hyaluronic acid injections
• Radiographically confirmed Kellgren-Lawrence I-II knee OA (mild knee OA; no bone-on-bone)
• Age 18-79 years

Exclusion Criteria:

• Presence of loose bodies on baseline magnetic resonance imaging
• Clinically and radiologically confirmed anterior/posterior cruciate ligament deficiences
• History of meniscal injury other than degenerative meniscal tears
• Previous knee surgery
• Presence of a degenerative meniscal tear causing mechanical symptoms such as locking, buckling, or give-way
• Intra-articular injection to affected knee within 6 weeks of intra-articular BMA injection
• Mechanical axis deviation greater than 7 degrees
• Intolerance to acetaminophen or hydrocodone (i.e., Vicodin)
• Use of non-steroidal anti-inflammatory drugs <1 weeks prior to BMA
• Injection of the joint scheduled for treatment within 3 months of BMA injection
• Body mass index of 30 or more
• History of drug abuse
• Current cigarette smokers
• Current use of systemic steroids
• History of or current alcohol abuse or dependence
• History of anemia, bleeding disorders, or inflammatory joint disease
• Active infection
• Active malignancy per medical or surgical history, diagnosed by primary case physician or treating specialist, undergoing treatment, has undergone treatment, or has declined treatment
• Inability to refrain from statin regimen from 1 month pre-injection to 1 month post-injection
• Pregnancy or breastfeeding at time of treatment
• Participating or planning to participate in a worker's compensation program at the time of treatment or follow-up period
• Pending or planned legal action pertaining to knee pain
• Non-English speaking