Viscosupplementation is a non-surgical treatment approach for osteoarthritis of the knee. It involves injecting hyaluronic acid into the knee joint space. Hyaluronic acid is a natural substance that is present in the synovial fluid of normal joints. The synovial fluid acts as a lubricant and shock absorber inside the knee joint. In osteoarthritis, the hyaluronic acid level in the synovial fluid decreases, resulting in damage to the articular cartilage. This helps to restore some of the density and viscosity of the synovial fluid.

How does Hyaluronic Acid Work?
Hyaluronic acid acts as a lubricant and shock absorber between the joints. When injected into the knee joint, it supplements the natural synovial fluid. This helps improve joint lubrication and cushioning. The increased viscosity and elasticity of the synovial fluid relieves pain and improves joint mobility by decreasing friction between the bones. Hyaluronic acid also possesses anti-inflammatory properties that reduce joint inflammation associated with osteoarthritis.

Benefits of Viscosupplementation
Some of the key benefits of this for osteoarthritis of the knee include:

- Reduced pain and improved function: This helps to decrease pain levels and improve physical function by restoring joint lubrication and cushioning.

- Delayed need for knee replacement surgery: It can postpone or eliminate the need for total knee replacement in some patients by providing pain relief and improved mobility.

- Restoration of synovial fluid properties: It adds volume and elasticity to the synovial fluid, helping to restore its lubricating and protective functions inside the knee joint.

- Anti-inflammatory action: Hyaluronic acid has anti-inflammatory properties that aid in reducing inflammation associated with osteoarthritis.

- Minimal side effects: This is generally a very safe treatment with minimal side effects like temporary joint pain, swelling or stiffness.

Steps to Perform Viscosupplementation
This is performed in the doctor's clinic through an injection directly into the knee joint space. The knee area is cleaned and numbing medication may be applied before injection. Under sterile conditions, a thin needle is inserted into the joint space and the hyaluronic acid supplement is injected carefully in small volumes. The number of injections can vary from one to five sessions, based on the response. Ice packs may be advised after injection to reduce pain or swelling. Gentle exercises can usually be resumed soon after completing the treatment.

Limitations of Viscosupplementation
While this provides benefits for pain management, there are certain limitations to keep in mind:

- Temporary relief: The effects are not long lasting and may not provide more than 6 months of pain relief.

- Varied response: Some patients respond better than others to the treatment. The degree of cartilage damage also influences the outcome.

- Cost factor: A full course of injections can be costly depending on insurance coverage and number of injections needed.

- Other therapies still needed: It should be used with weight management, exercise and braces as complementary treatments.

- Unsuitable for severe OA: Viscosupplementation works best for mild to moderate osteoarthritis. It may not help in late stage severe OA cases requiring joint replacement.

Thus, while viscosupplementation presents a non-surgical option for managing osteoarthritis of the knee, the treatment response can vary among individuals. It works best when combined with other lifestyle changes and therapies for long term management of the condition