This randomized trial seeks to investigate the difference if any between cortisone injection versus bone marrow aspirate injection in the glenohumeral joint of patients with confirmed osteoarthritis. The investigators hope that results from a prospective randomized controlled pilot study on bone marrow aspirate (BMA) glenohumeral joint (GHJ) injections will provide valuable early information on an alternative treatment for GHJ osteoarthritis (OA). This novel study will also contribute clinical data to the growing pool of research around BMA in the treatment of osteoarthritis. This study has the potential to uncover a new and more effective therapy to add to the arsenal of an orthopaedic surgeon in the management of GHJ OA. This would provide improved care and treatment for those disabled by GHJ OA. Additionally, this knowledge would be applicable to a variety of medical practitioners who treat GHJ OA from the general orthopaedic surgeon to pain subspecialists.

Glenohumeral joint (GHJ) osteoarthritis (OA) is a painful, progressive and debilitating condition that impairs quality of life. Currently, the only "cure" for arthritis is total joint replacement. This is a major operation that carries with it significant risks including infection, stiffness, limited range of motion, peri-prosthetic fracture and loosening. Furthermore, there are permanent post-operative restrictions, and in young or active people there is a significant rate of early revision surgery. Therefore, the goal of early shoulder OA management is symptom control, and postponement or prevention of the need for joint replacement.

Initial management options include physical therapy, pain-control medications, and intra-articular injections. Corticosteroid injections are the most commonly utilized injectables used in GHJ OA, with previous studies reporting good, short term pain relief and clinical improvement with corticosteroid injections for shoulder OA. However, corticosteroid injections may damage the collagen matrix of tendons and ligaments around the shoulder with repeated injections. Intra-articular hyaluronic acid (HA) injections have been proposed as an alternative to corticosteroid injections, and have demonstrated a clinically significant improvement in pain and function, albeit with a limited effect size.

Bone marrow aspirate concentrate (BMA) injections is a relatively recent option for the treatment of OA. BMA is a biological product that is produced through the centrifugation of the patient's own bone marrow, producing a cellular equivalent to iliac crest bone graft. This aspirate has been shown to contain, among other nucleated cells, mesenchymal stem cells (MSC's) and hematopoietic stem cells (which can directly convert to stromal MSC's).Furthermore, this minimally invasive procedure can be conducted as an outpatient procedure, saving operating room time.

Preliminary studies on intra-articular knee injections of BMA for early OA have reported statistically significant benefits in improved pain scores and function, with few adverse effects. The mechanism of action is likely through paracrine effects exerted by MSCs with the upshot being anti-inflammatory and potentially regenerative capabilities. These results are encouraging for the use of BMA in the shoulder, which is a non-weight bearing joint. Therefore, the investigators believe that the clinical improvements seen with BMA injections for knee OA will also be seen in the shoulder to an equal or greater extent.

To date there are no trials investigating injectable stem cell therapies in the shoulder. The investigators aim to conduct a randomized controlled study to test the safety and efficacy of BMA injections for the treatment of early to mid-stage GHJ OA.

1.2 Significance of Current Study

Results from a prospective randomized controlled pilot study on BMA GHJ injections will provide valuable early information on an alternative treatment for GHJ OA. This novel study will also contribute clinical data to the growing pool of research around BMA in the treatment of osteoarthritis.

This research group is proposing a randomized clinical trial prospectively comparing BMA GHJ injections versus Depo Medrol Cortisone GHJ injections. This study will include comprehensive clinical, functional and joint specific patient outcome scores.

After a comprehensive literature review, to the investigators knowledge, there are no studies on the efficacy of BMA injections for management of GHJ OA. Thus, this study will be the first to report on safety, efficacy and costs associated with BMA injections.

This innovative study has the potential to uncover a new and more effective therapy to add to the arsenal of an orthopaedic surgeon in the management of GHJ OA. This would provide improved care and treatment for people disabled by GHJ OA. Additionally, this knowledge would be applicable to a variety of medical practitioners who treat GHJ OA from the general orthopaedic surgeon to pain subspecialists.

Inclusion Criteria:

• Men or women above the age of 18 - 65
• Primary diagnosis of glenohumeral joint osteoarthritis (Samilson and Prieto Stage 1, 2 or 3)
• Provision of informed consent

Exclusion Criteria:

• Prior condition (such as trauma, avascular necrosis, fracture, iatrogenic or chondrolysis) resulting in secondary osteoarthritis
• Previous surgical intervention for GHJ OA
• Previous injection of cortisone or other substance
• Inability to comply with rehabilitation or form completion
• Likely problems, in the judgement of the investigators, with maintaining follow-up (i.e. patients with no fixed address, patients not mentally competent to give consent, etc.)
• WSIB involvement
• Lawsuit involvement