Osteoarthritis is a degenerative joint disease characterized by the progressive breakdown of cartilage, the smooth tissue that cushions the ends of bones. This deterioration leads to pain, stiffness, and reduced mobility. While traditional treatments focus on managing symptoms, biologics are an emerging category of therapies. These treatments use substances from the body to address the underlying biological processes of the disease, primarily in earlier stages of osteoarthritis.
Understanding Biologic Therapies
Biologic therapies are treatments derived from living organisms, such as human cells, rather than being synthesized chemically. This sets them apart from conventional treatments like nonsteroidal anti-inflammatory drugs (NSAIDs). While an NSAID works broadly to reduce pain systemically, biologics are designed for targeted, cellular-level work within the joint. The goal is to introduce a concentrated amount of specific proteins, growth factors, or cells directly to the site of injury. The substances used are autologous, meaning they are harvested from the patient’s own body, which minimizes the risk of immune rejection or disease transmission.
Types of Biologic Injections for Osteoarthritis
Platelet-Rich Plasma (PRP) is one of the most widely studied biologic treatments. The therapy begins with a blood draw, and a centrifuge is used to concentrate platelets into a small volume of plasma. This PRP is then injected directly into the arthritic joint. The rationale lies in the high concentration of growth factors within platelets, which are released after injection. These factors are believed to reduce inflammation, inhibit destructive enzymes, and signal local cells to promote tissue maintenance.
Another treatment uses mesenchymal stem cells (MSCs), often called medicinal signaling cells. For osteoarthritis, these cells are harvested from the patient’s bone marrow or adipose (fat) tissue. The proposed mechanism for MSCs is twofold. It is believed they can differentiate into new cartilage cells, though the extent of this is still under investigation. More significantly, MSCs exert influence through paracrine signaling, releasing anti-inflammatory molecules and growth factors to modulate the joint’s environment.
Alpha-2-Macroglobulin (A2M) injections are a more recent approach. A2M is a large protein in blood plasma that functions as a protease inhibitor, trapping and neutralizing enzymes that are destructive to cartilage. In an osteoarthritic joint, these enzymes are directly responsible for breaking down the cartilage matrix. The therapy involves drawing blood and using a specialized system to concentrate the A2M protein for injection. This aims to halt or slow the progression of cartilage degradation by reducing the concentration of these destructive enzymes.
The Treatment Procedure
The procedure for biologic injections is a multi-step process often completed in a single visit. The first step is harvesting the biological material. For PRP or A2M, this is a standard blood draw, while MSC therapies require either a bone marrow aspiration from the pelvic bone or a small-scale liposuction, both performed under local anesthesia.
The harvested material is then processed in a centrifuge. This machine separates and concentrates the desired platelets, stem cells, or proteins into a small, injectable volume while the patient waits.
The final step is the injection, which demands precision. Clinicians use ultrasound guidance to visualize the needle in real-time as it passes through tissue, confirming its placement directly within the joint and avoiding nerves or blood vessels.
After the injection, patients receive specific aftercare instructions. They are advised to rest the joint and avoid strenuous activities for a period ranging from days to weeks. Patients are also instructed to avoid NSAIDs, as these drugs could interfere with the intended biological processes.
Efficacy and Regulatory Standing
The clinical effectiveness of biologic injections is still under investigation. While many smaller studies suggest that treatments like PRP and stem cell injections can reduce pain and improve function, results from large-scale clinical trials have been mixed. This variability may be due to a lack of standardization in how the biologics are prepared, the concentration of active components, the patient’s arthritis stage, and the injection technique.
The regulatory status is a significant consideration. In the United States, the Food and Drug Administration (FDA) has not approved most of these therapies specifically for treating osteoarthritis. Because they lack specific FDA approval, these therapies are considered investigational and are not covered by insurance, requiring patients to pay out-of-pocket.
Because these treatments use a patient’s own biological materials, the risk of an allergic reaction or immune rejection is very low. The most common side effects are temporary and related to the injection, including localized pain, swelling, or bruising. As with any procedure that breaks the skin, there is a small risk of infection. Patients considering these therapies should have a thorough discussion with their doctor about the current evidence and potential risks.