Joint discomfort, caused by osteoarthritis, is a common condition in older canine (and feline) patients. When surgical correction of the underlying condition has already been pursued or is not an option, joint injections can play an important role in the management of arthritis pain. These injections are delivered in sterile under light sedation via small needles directed into the joint, or intra-articular. All joint injections work best when combined with other methods of medical management for osteoarthritis. There are several options for joint injections. It is important to note that none of these injections can reverse cartilage loss in the joint. Early intervention is key to decrease inflammation, pain, and slow the progression of cartilage damage.
Hyaluronic Acid
Hyaluronic Acid, or HA, is a component of normal synovial joint fluid. Its role is to decrease friction in the joint. The concentration of HA can decrease in joints with age. By injecting HA, we can promote a thicker, more protective joint fluid in cases of mild to moderate osteoarthritis. Typically, HA is combined with other joint injections to increase efficacy.
Platelet rich plasma
Platelets are a component of the blood that is mainly involved in the coagulation (clotting) cascade. However, platelets also have a role in injury healing via cytokines and growth factors. These items attract other cells, such as macrophages, to the inflamed/wounded area and activate cells, such as fibroblasts, to repair the damaged tissues.
Platelet rich plasma (PRP) is a concentrated portion of the blood with an increased number of platelets. Blood is removed from a patient’s vein and placed in a centrifuge. The various components of blood are separated into layers by this centrifuge. After the spin cycle is complete, the platelet rich plasma layer is separated from the remaining blood components. This PRP is then injected intra-articular to decrease inflammation and promote healing of tissues. Autologous condition plasma, or ACP, is a similarly isolated product that can be injected into joints/tissues.
PRP has also shown promise in the healing of tendons, ligaments, muscle, and skin wounds.
Side effects are minimal but may include mild discomfort, irritation, or bleeding at the venipuncture and injection sites.
On a theoretical level, PRP is a strong therapy against inflammatory conditions like osteoarthritis. However, in-depth research is limited regarding the clinical efficacy of regenerative medicine in veterinary patients. Several small clinical trials show positive outcomes associated with PRP. However, this injection is rarely used by itself but rather via a multi-modal approach, making it difficult to obtain a definitive assessment of PRP’s impact.
Steroids
Steroids given within the joint have similar, but more targeted effects. These injections directly reduce inflammation and the pain associated with inflammation. While often very effective initially, steroid injections are often reserved for older, end-stage osteoarthritis patients. The effects can wane over time, and multiple injections may have a negative impact on the remaining cartilage. Side effects can be similar to systemic steroids- increased drinking/urination, appetite, or panting.
SpryngTM
SpryngTM injections manage osteoarthritis through a different mechanism. Instead of treating inflammation directly or stimulating tissue healing, it addresses the mechanical friction that occurs with damaged cartilage in osteoarthritic animals. These injections deliver a shock-absorbing matrix that creates a “cushion” in the joint fluid to improve comfort. With this improved joint function, the recurring inflammatory stimulus is reduced, leading to a healthier joint.
Synovetin OA®
Synovetin OA® contains a radioactive isotope that targets pro-inflammatory macrophages. The decrease in macrophages leads to a subsequent decrease in inflammation and associated pain. For more information, please see our page dedicated to Synovetin OA®.
During your consultation, you will discuss which of these injections may be appropriate for your pet. Not all patients will respond the same to a joint injection, and the duration of clinical improvement can be variable. Given the progressive nature of osteoarthritis, early intervention with a multi-modal approach is recommended to provide a good quality of life to your pet for as long as possible.