Hyaluronic acid infiltrations are injected into the joints as a lubricant if the body’s own substance has been lost over the years or after an injury.
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What is hyaluronic acid?
Hyaluronic acid (trade names: Hyalgan, Hyalart, Curavisc, etc.) is used to treat osteoarthritis (joint wear).
The most common use is hyaluronic acid in knee osteoarthritis, but it can also be injected into the hip joint in saddle joint arthrosis (rhizarthrosis) between wrist and hand or in hip joint arthrosis (coxarthrosis).
In the last two cases, an ultrasound control is performed to find the exact place where the infiltration should take place.
The injection can also be made into the shoulder joint, but this joint is exposed to less stress because it does not have to bear the body weight.
In a healthy joint, the bone ends are covered with a layer of cartilage.
The cartilage supports the smooth movement of the joint-forming bones and lubricates the bone ends. In osteoarthritis, there is a wear of the cartilage layer, which becomes thinner and thinner.
This degenerative process takes away the protective layer of the bone ends and the joint movement loses its suppleness.
Hyaluronic acid is a natural component of the joints and other parts of the body.
In the joint, it is an important component of the articular cartilage and synovial fluid (synovia), which as a lubricant improves the lubricity of the joints.
In osteoarthritis, the cartilage layer is too thin to lubricate the joint sufficiently.
Injecting synthetic hyaluronic acid into the joint affected by cartilage changes can improve the sliding movement of bones.
As a rule, these infiltrations are prescribed for knee joint osteoarthritis when the knee pain could not be relieved by other treatment measures.
Joints are like gears, they run much better when they are lubricated.
A healthy joint contains a substance called synovial fluid or synovial fluid and prevents the bones from rubbing against each other.
The synovial fluid also has a shock-absorbing function.
Hyaluronic acid is the main component of synovial fluid, but in osteoarthritis it is broken down.
The loss of hyaluronic acid leads to stiffness and joint pain.
Can hyaluronic acid infiltrations relieve the symptoms of osteoarthritis?
Hyaluronic acid injections (the so-called viscosupplementation) are recognized by the American Food and Drug Administration (FDA) for the treatment of knee osteoarthritis; some doctors also use this therapy in other joints, such as the hip and ankle.
Studies on hyaluronic acid injections have rarely yielded disappointing results; Many doctors who treat osteoarthritis believe that the scientific evidence and clinical experience shows that an injection into the knee joint can provide great relief.
In addition, laboratory and clinical research assume that the range of action of hyaluronic acid is not only in the lubrication of a creaking joint, but extends much further.
Hyaluronic acid infiltrations can be helpful in a complete meniscus removal (total meniscectomy), because the meniscus favors the sliding movement of the bones and protects the cartilage.
What are the indications?
The idea of using hyaluronic acid to treat osteoarthritis was first put forward in the 70s by the Hungarian scientist Endre A. Balazs.
In 1987, hyaluronic acid treatments were used abroad, although the first preparation available in the United States was not recognized by the FDA until 10 years later, it is called Hyalgan.
There are currently five hyaluronic acid treatments for knee osteoarthritis in the United States.
Most preparations are made from an unusual substance, namely cockcombs, while others are made from bacteria.
Hyaluronic acid injection is a form of treatment that doctors prescribe in the following cases:
- · The patient can no longer control the osteoarthritis-related pain with ibuprofen or other anti-inflammatory drugs (NSAIDs).
- · The patient does not tolerate the medication (side effects such as stomach irritation, bleeding and kidney damage may occur).
A hyaluronic acid treatment involves 3 to 5 injections into the joint at weekly intervals. For many patients, this therapy brings an improvement in pain.
Which hyaluronic acid preparations are commercially available?
The hyaluronic acid injections are intended to supply the body with natural nutrients that it has lost.
The procedure is simple, the hyaluronic acid is injected directly into the knee joint space.
A typical course of treatment involves one injection weekly for three to five weeks.
Hyaluronic acid injections have been recognized by the FDA to treat patients with knee osteoarthritis, but they are sometimes used successfully in other joints as well.
Hyaluronic acid is available under various trade names, including:
- Curavisc
- Hyalgan (high molecular weight)
- Hyalart
- Hyalubrix
- Synvisc-One (medium molecular weight)
Treatment with hyaluronic acid infiltrations
If the knee joint is severely swollen (effusion), the doctor will suck out the excess fluid before injecting the hyaluronic acid.
These two procedures can usually be performed within the same session and with the same needle inserted into the joint, although some doctors prefer two syringes.
Depending on the product, three to five injections are given within a few weeks.
The treatment takes place in the doctor’s office, so you do not need to go to the hospital.
Method of
injection
Hyaluronic acid is available in 2 ml ampoules (one injection per ampoule) or as a pre-filled syringe.
The recommended frequency of administration is one syringe per week, over a period of 5 weeks for Hyalgan and 3 weeks for Hyalubrix or Synvisc-One.
After 6 months, therapy can be repeated.
The injection into the knee joint can be done in two different ways.
1. The patient lies in a supine position on the treatment table, the knee joint is bent (approx. 90°).
In this position, the inner and outer areas of the joint can easily be felt as small pits inside or outside the lower kneecap. In this case, the joint access is under the kneecap, laterally of the origin of the kneecap tendon.
2. Or the patient lies on his back with his legs stretched to make the infiltration into the knee joint. The exact puncture site is located between the femur and the upper outer edge of the kneecap; however, other points close to the edge of the kneecap can also be selected.
When injecting into the stretched knee joint, the needle is usually directed under the kneecap.
Results of hyaluronic acid infiltrations
Infiltration with hyaluronic acid can bring benefits to patients for whom other therapies have not led to the desired success.
The efficiency is significantly higher in the initial stage of osteoarthritis (mild to moderate). Some patients feel pain at the injection site, rarely the infiltrations lead to increased swelling.
The long-term effect of hyaluronic acid injections is not yet sufficiently known; this area is constantly being explored.
This treatment option should be discussed with the doctor if the osteoarthritis does not respond well to other treatments or if surgery is to be delayed.
Cost
Hyaluronic acid is not cheap. In the pharmacy, the average price for five ampoules ranges from 150 – 250 € (30-50 € per ampoule).
A pack of three pre-filled syringes costs between 150 and 200 € wholesale.
Effect of hyaluronic acid infiltrations
It has been shown that hyaluronic acid injections could improve pain symptoms in many cases where other treatment measures and painkillers were unsuccessful.
This technique has been practiced in Europe and Asia for years, but it was not until 1997 that it was recognized by the “US Food and Drug Administration”, although this recognition refers only to the treatment of knee osteoarthritis.
In the meantime, various hyaluronic acid preparations are commercially available.
Immediate effect
Hyaluronic acid does not have an immediate effect like a painkiller.
Immediately after the injection, local reactions may occur, such as pain, warming and a slight swelling.
As a rule, these symptoms are short-lived.
If an inflammation forms, an ice pack or cooling pack should be applied.
For the first 48 hours after the injection, the leg should not be overloaded: long standing, jogging and lifting heavy objects should be avoided.
Long-term effect
The first injection can already provide relief from pain in the knee.
Hyaluronic acid appears to have an anti-inflammatory and analgesic effect.
The injections can also stimulate the organism to an increased self-production of hyaluronic acid in the joints.
How many infiltrations are necessary and at what intervals are they injected?
The effect of the injections lasts for several months, usually the treatment provides for three injections within a year or every 6 months.
Are the injections painful?
No, they cause a slight discomfort and less pain than an injection into the gluteal muscle; however, patients with severe knee pain may find the puncture painful.
What precautions must be taken?
After injection
• Knee-straining activities, including sports such as jogging and tennis, but also long standing should be avoided in any case until about 48 hours after the injection.
Infection
• Hyaluronic acid injections cannot be made if there is an infection in the joint or a skin disease in the puncture area.
Blood circulation
• Hyaluronic acid injections must not be performed in case of circulatory disorders in the legs.
• The doctor must be informed of any significant swelling or blood clots in the legs.
Contraindications
Unlike cortisone infiltrations, infiltrations with hyaluronic acid have almost no contraindications. That is why this form of treatment is used very often.
Allergy
• Hyaluronic acid must not be injected if an allergic reaction to hyaluronic acid preparations has already occurred.
• The doctor must be informed if allergic reactions to bird products such as feathers, eggs and poultry are known.
Interaction with other medicinal products
• The doctor needs to know exactly what medications the patient is currently taking. This also includes over-the-counter medicines and natural medicinal plants from the drugstore.
• The doctor must also be informed about which therapies have already been carried out against osteoarthritis.
At a first visit to the doctor, the patient must present his medical history; this also includes whether pregnancy is present or breastfed.
• Hyaluronic acid has not been tested on pregnant and lactating women.
• The doctor must also be informed whether there are currently pregnancy intentions.
Side effects
Along with the desired treatment results, unwanted side effects may also occur.
These may need to be addressed.
Together with the doctor or nurse, it should be checked if any of the following side effects occur:
- frequently:
Difficulty moving
Muscle pain or stiffness
Joint pain
- less common:
Swelling or redness of the joint.
- seldom:
Bleeding, blistering, overheating, feeling cold, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, numbness, pain, rash, redness, numbness, tingling, swelling, ant running, ulceration or heat at the injection site.
Further side effects occur in very rare cases and are not mentioned here.
If other signs and symptoms become noticeable, a doctor must be consulted.
There may also be side effects that do not require a doctor’s visit.
These can occur during treatment once the body has absorbed the drug.
In any case, the doctor should inform the patient how to prevent and mitigate certain side effects.
