Hyaluronic acid has been successfully used for years to treat osteoarthritis, particularly knee osteoarthritis. The substance, which occurs as a natural component of the body in synovial fluid, can help lubricate the joints and improve their mobility, which can alleviate pain and increase quality of life. Studies have shown that the injection of hyaluronic acid, especially in dry forms of osteoarthritis, i.e., without inflammatory processes or joint effusion, often has a positive effect. In inflammatory osteoarthritis, however, the success rate is usually lower, as hyaluronic acid is not as effective in this case.

In the knee joint, hyaluronic acid can alleviate pain and possibly slow down cartilage degradation by acting as a kind of "lubricant". Here, a distinction is made between low-molecular and high-molecular hyaluronic acid, which remain in the joint for different lengths of time and have different effects. Low-molecular hyaluronic acid has the potential to penetrate the joint more quickly and provide quick relief for mild to moderate forms of arthritis, while high-molecular variants tend to have a longer-lasting effect but are less incorporated into the cartilage.

Hyaluronic acid is also used for the hip joint, although its use there is associated with somewhat higher risks. When injecting into the hip, complications such as injuries to nerves or blood vessels in the groin area can occur due to the location and access. Therefore, a careful assessment is often made here as to whether hyaluronic acid is actually the appropriate therapy.

When using hyaluronic acid in osteoarthritis, the molecular weight of the substance used plays an important role in the effectiveness and durability of the treatment. Hyaluronic acids are available in low and high molecular weights, and both variants have different properties and application benefits.

Differences in the molecular weight of hyaluronic acid

• Low molecular weight hyaluronic acid has a lower molecular weight and can penetrate into the joint tissue more quickly. It usually works in the short term and is preferably used in mild to moderate osteoarthritis. Since it is broken down more quickly, multiple injections are necessary to maintain the effect over a longer period of time. Its small size also means that it is well distributed in the tissue, but often offers lower mechanical stability.
• Hochmolekulare Hyaluronsäure ist durch ihre größere Molekularstruktur viskoser und verbleibt länger im Gelenk. Diese Variante wird häufig bei fortgeschritteneren Arthrosefällen eingesetzt, da sie das Gelenk besser „abpolstern“ kann und entzündungshemmende Eigenschaften besitzt. Hochmolekulare Hyaluronsäuren bieten oft eine längere Schmerzlinderung, aber der Effekt ist verzögert und tritt meist nach mehreren Wochen ein​

Dosage and therapy course: The hyaluronic acid treatment

A typical hyaluronic acid therapy for knee osteoarthritis often involves a series of injections over several weeks. The classic hyaluronic acid course with five injections is a common method in which a dose is injected into the affected joint over five weeks. The gradual administration ensures that the hyaluronic acid is optimally distributed and the viscoelastic properties of the gel in the joint have the best possible effect.

The effect of this treatment varies: patients often report a gradual improvement in their symptoms after about two to three injections. The gradual approach is intended to gradually relieve the joint and promote natural regeneration, while the joint space is lubricated again and pain is reduced

Frequency of application of hyaluronic acid

The dosage can vary depending on the type of hyaluronic acid and the manufacturer. There are low-dose preparations that need to be injected more frequently, and high-dose products that are administered at longer intervals. The decision on the dosage and injection rhythm depends on the disease progression, the joint situation, and the patient's response to treatment. High molecular weight hyaluronic acids often require fewer sessions as they remain in the joint for longer.

Hyaluronic acid in osteoarthritis: what is it, and how does it work?

Hyaluronic acid is a natural component of cartilage and synovial fluid and plays a central role as a 'lubricant' in the joints. In osteoarthritis, a degenerative joint disease, the synovial fluid is often less viscous and the cartilage is worn out, which impairs mobility and causes pain. In the treatment, hyaluronic acid injections are injected into the affected joint to improve gliding ability and achieve some pain relief. The effect often only sets in after several weeks and can vary in strength from patient to patient.

When does hyaluronic acid help with knee osteoarthritis?

Hyaluronic acid is particularly commonly used for knee osteoarthritis and can improve mobility and alleviate pain in certain cases, especially in "dry" arthrosis where inflammation and swelling in the joint are not prominent. In mild to moderate osteoarthritis, many patients show a significant improvement in symptoms, making hyaluronic acid a popular additional option. However, in advanced osteoarthritis or inflammatory forms with severe irritation and joint effusions, the benefit is often lower, as the inflammatory process can impair the effect.

Hyaluronic acid in hip osteoarthritis: risks and benefits

Hyaluronic acid can also be used in the hip joint, but the injection is technically more demanding because nerves and blood vessels run close together in the groin. Due to the higher risk of injury, the injection must be performed under strict medical supervision. Moderate success can be seen in non-inflammatory forms of hip osteoarthritis, but the effect is often less than that seen in knee osteoarthritis. Additionally, some experts point out that the use of hyaluronic acid in hip osteoarthritis is less researched and therefore more controversial than in the knee area.

Hyaluronic acid: risks, side effects, and controversies

Although hyaluronic acid injections are generally well tolerated, side effects such as pain, swelling, redness or, in rare cases, allergic reactions can occur. In the event of an overreaction, treatment can be discontinued. Studies show that only about half of patients experience a benefit and have to bear the treatment costs themselves, as statutory health insurance companies in Germany consider hyaluronic acid injections to be an individual health service (IGeL).

Scientific standpoint on the effectiveness of hyaluronic acid

The scientific opinion on the effectiveness of hyaluronic acid is divided. While some studies show that the acid brings a moderate improvement in non-inflammatory osteoarthritis, organizations such as the "Stiftung Warentest" point out that the effectiveness of the treatment is disputed. Most positive effects appear to be temporary in nature, and long-term studies on pain relief and functional improvement are currently lacking. Therefore, statutory health insurance companies generally do not cover the costs of treatment with hyaluronic acid.

Conclusion: When is hyaluronic acid useful?

Hyaluronic acid injections are a possible treatment option depending on the degree of osteoarthritis, molecular weight, and individual response. While the hyaluronic acid treatment with five injections can support the long-term lubrication and regeneration of the joint, other dosages and molecular weights are also effective. For many patients, detailed advice is crucial to choose the appropriate therapy form.

Hyaluronic acid in osteoarthritis can be an option, especially for patients with dry knee osteoarthritis and low-grade inflammation. In hip osteoarthritis and advanced joint destruction, however, expectations are rather low. Each patient should individually weigh the pros and cons in consultation with ENDOPROTHETICUM whether such treatment is useful and what alternatives are available.