Intra-articular hyaluronic acid injections are a minimally invasive surgical procedure to treat pain and inflammation associated with arthritis, particularly osteoarthritis of the knee. The procedure may also be referred to as viscosupplementation, a process that aims to restore the physiological and rheological state of the joint tissues. Intra-articular therapy, being an invasive procedure, requires strict aseptic technique.
Normal joint function is maintained by the synovial membrane and synovial fluid, which nourishes the chondrocytes and eliminates matrix degradation and metabolites. HA is produced in the synovial lining cells to help protect and maintain the articular cartilage. The clinical symptoms experienced by osteoarthritic patients are due to the inflammation of the synovium. Intra-articular injection decreases pain, discomfort, stiffness, and other OA symptoms, allowing extensive movement of the joint.
How does hyaluronic acid injection work?
The exact mechanism of action of hyaluronic acid injection has yet to be established, but it is proposed to provide OA benefits and pain relief by:
- Restoring the concentration of HA in the joints;
- Protecting cartilage cells from damage;
- Reducing cartilage cells apoptosis (cell death);
- Reducing inflammation by suppressing the binding of interleukin to its receptors;
- Blocking sensitised nociceptive nerve endings to relieve pain;
- Increasing the production of hyaluronic acid in the affected joint.
Hyaluronic Acid Injections Safety and Efficacy
Although HA injections are used in various arthritic joints, the vast majority of clinical trials have been performed in the knee and hip. Patients who are allergic to eggs and chicken should not be administered with chicken-comb derived products. The most common side effects associated with intra-articular injection of hyaluronic acid do not always require medical attention. They may go away in a few days or weeks as the patient’s body adjusts to the treatment.
Common Side Effects:
- Muscle pain
- Difficulty moving the injected joint
Less Common Side Effects:
- Lump formation