One of the treatment methods we use to reduce pain and increase functionality in joint and tendon pain, which is a general health problem, is hyaluronic acid injections.
What Is Hyaluronic Acid?
Hyaluronic acid is named after the Greek word “Hyalos“. This word means glass, and it was given this name because of its shiny and transparent appearance. Hyaluronic acid is the main component of synovial fluid. It is naturally found in the body. It is a high-molecular-weight glycosaminoglycan produced by synoviocytes, chondrocytes, and fibroblasts.
It is responsible for the nutrition of joints and bones and the provision of lubrication. A healthy knee contains 2.5-4 mg/ml of hyaluronic acid.
In osteoarthritis, the amount of hyaluronic acid decreases by up to 50% due to decreased production and increased destruction. It is poorly absorbed when taken orally. Therefore, it is preferred to be given by injection into the joint.
How Does Hyaluronic Acid Injection Work?
The exact mechanism of action is not clear. It is thought that it may have many effects such as reducing friction, improving elasticity and shock absorption in the knee joint, increasing the flexibility of the cartilage, increasing the lubricity of the joint surfaces that are impaired by the decrease in joint fluid, forming a protective barrier on the synovial membrane and joint surface, reducing the inflammatory response in the joint.
It is also reported to suppress pain perception and reduce tissue destruction. The half-life of externally injected hyaluronic acid is 2-8 days.
However, clinical improvement is observed 6 months-1 year after injection. This is thought to be related to the increase in hyaluronic acid synthesis in the body with external injection.
Is The Molecular Weight Of Hyaluronic Acid Important?
Low and high molecular weight preparations are available. There is conflicting information on this subject. It has been reported that the molecular weight should be at least 500.000 Daltons.
What Diseases Are Hyaluronic Acid Injections Beneficial For?
- Osteoarthritis of the knee
- Osteoarthritis of the hip
- Temporomandibular joint (TMJ) injection
- Osteoarthritis of the shoulder/ankle
How To Decide Which Of The Available Injection Treatments To Choose?
The treatment plan is made by evaluating the patient’s age, clinical findings, X-ray findings, expectation from the treatment, and previous treatments.
How Long Is The Efficacy After This Injection?
An efficacy of between 6 months and 1 year has been reported.
What Are The Side Effects Of Hyaluronic Acid Injections?
This injection is very safe. Side effects are very rare and temporary. There is no known drug interaction. However, redness, heat increase, swelling, tenderness, pain may occur at the injection site.
Can Hyaluronic Acid Be Combined With PRP?
Yes, studies have reported that when these two injections are given in combination, the efficacy is better than when they are given alone. However, the cost increases. At the same time, more volume is given during intra-articular injection.