Hyaluronic acid (HA) is a key molecule in various fields of medicine due to its unique hydration and lubrication properties. This article will focus on the uses of HA for treating musculoskeletal, tendon, and joint disorders, exploring its applications, benefits, and the most advanced administration techniques.
Definition and Composition of Hyaluronic Acid
Hyaluronic acid is a glycosaminoglycan, a long polysaccharide chain composed of repetitive units of D-glucuronic acid and N-acetylglucosamine. It is a fundamental component of connective tissue, naturally present in the synovial fluid of joints, skin, eyes, and other areas of the body. Its main characteristic is the ability to bind large amounts of water, providing viscoelasticity and lubrication to the tissues in which it is found.
How Hyaluronic Acid Is Produced
In the past, hyaluronic acid was extracted from animal tissues, such as rooster combs, but this method carried risks of allergic reactions. Today, HA is primarily produced through bacterial fermentation. The most commonly used strain is Streptococcus zooepidemicus, which ensures highly controlled, safe, and purified production. This biotechnological process has made hyaluronic acid accessible for a wide range of therapeutic applications.
Types of Hyaluronic Acid: Molecular Weight and Properties
Hyaluronic acid is classified based on its molecular weight, which can be low, medium, or high. This parameter significantly affects its properties and, consequently, its medical applications:
Low Molecular Weight (20-200 kDa): Has a greater ability to penetrate tissues, promoting deep hydration. It is often used in dermatological products for skin regeneration.
Medium Molecular Weight (500-1,000 kDa): Offers a balance between penetration and the ability to bind water. It is often used in fillers and aesthetic treatments.
High Molecular Weight (1,000-4,000 kDa): Has a high capacity to retain water, providing viscosity and viscoelasticity. In orthopedics, it is used to improve joint lubrication and reduce friction during movement.
Properties of Hyaluronic Acid
The main properties of hyaluronic acid that make it so valuable in medicine are:
Hydration: Thanks to its ability to bind water, HA maintains tissue hydration.
Lubrication: In joints, it improves the quality of synovial fluid, reducing friction between joint surfaces.
Wound Healing: It stimulates cell proliferation and promotes tissue regeneration.
Anti-inflammatory: It reduces inflammatory processes by modulating the immune response.
Medical Uses of Hyaluronic Acid
Hyaluronic acid is used in various medical fields:
Dermatology: Used in facial filler injections and as an ingredient in moisturizing creams to improve skin elasticity and reduce wrinkles.
Ophthalmology: In ophthalmic solutions to hydrate and protect the ocular surface, for example, in cases of dry eyes.
Aesthetic Surgery: For reshaping the face, improving the appearance of scars, and increasing tissue volume.
Orthopedics: To treat joint and musculoskeletal disorders, playing a crucial role in improving the quality of life for patients with chronic conditions.
Why Is It Used in Joints, Tendons, and Muscles?
Once injected, hyaluronic acid acts by improving the quality of synovial fluid, reducing inflammation, and promoting a more stable joint environment. This reduces friction between joint surfaces, improving mobility and reducing pain. Additionally, it has been shown to have protective effects on cartilage, slowing the degenerative process of joints, as seen in osteoarthritis.
Hyaluronic acid is administered in various musculoskeletal structures for the following reasons:
Joints: To improve lubrication and reduce pain associated with conditions such as osteoarthritis.
Tendons: To promote tendon regeneration and reduce inflammation, as in the case of chronic tendinitis.
Muscles: To reduce adhesions and improve muscle regeneration after injury.
Injection Technique of Hyaluronic Acid
Hyaluronic acid injections can be performed with or without ultrasound guidance. However, the ultrasound-guided technique is superior for several reasons:
Precision: Ultrasound allows for real-time visualization of the needle's position, ensuring that hyaluronic acid is injected exactly into the target area.
Safety: It reduces the risk of damage to surrounding tissues or injections in incorrect sites.
Efficacy: It ensures optimal distribution of the product, maximizing therapeutic benefits.
Ultrasound-Guided Injection Procedure
The patient is positioned to ensure that the joint or tendon is easily accessible.
A conductive gel is applied to the skin, and the ultrasound probe is used to locate the area to be treated.
The needle is inserted under ultrasound guidance, and hyaluronic acid is precisely injected into the affected area.
After the injection, the area is briefly monitored to ensure that the product has been distributed correctly
Indications for Hyaluronic Acid in Joints, Muscles, and Tendons
Osteoarthritis: Improvement of joint function and reduction of pain.
Chronic Tendinitis: Acceleration of the healing process and reduction of inflammation in conditions such as epicondylitis or Achilles tendonitis.
Muscle Injuries: Improvement of muscle regeneration.
Cartilage Injuries: Protection and regeneration of damaged cartilage.
Contraindications
Absolute Contraindications
Local infection in the area to be treated.
Known allergy to hyaluronic acid or its components.
Pregnancy or breastfeeding (in some cases).
Relative Contraindications
Recent treatment with corticosteroids.
Bleeding disorders or use of anticoagulants.
Patients with uncompensated systemic diseases (e.g., uncontrolled diabetes).
Benefits of Hyaluronic Acid Therapy
The scientific literature strongly supports the benefits of hyaluronic acid in the treatment of joint and musculoskeletal disorders. Clinical studies demonstrate that:
It significantly reduces pain and inflammation in osteoarthritis compared to placebo treatments.
It slows the progression of degenerative joint damage, helping to maintain functionality and mobility.
It improves the quality of life for patients with chronic tendinopathies, increasing their ability to perform daily activities without pain.
It reduces the number of surgical interventions needed in cases of severe joint degeneration, offering an effective conservative alternative.
Possible Side Effects
Although hyaluronic acid is generally considered safe, some side effects may occur, especially in cases of intra-articular or intratendinous administration. The most common include:
Local Reactions: Such as pain, swelling, redness, and warmth at the injection site. These symptoms are usually transient and resolve within a few days.
Allergic Reactions: In rare cases, allergic reactions, including severe ones, may occur in sensitized individuals.
Infection: Although rare, there is a risk of infection following injections, making it essential to follow aseptic procedures.
Hematomas: Hematomas may form at the injection site, especially if the needle damages surrounding blood vessels.
Conclusion
Hyaluronic acid is a valuable ally in the treatment of musculoskeletal and joint disorders. Its unique characteristics, such as high hydration and lubrication capacity, make it a versatile therapeutic choice for conditions like osteoarthritis, tendinitis, and cartilage injuries. Injections of hyaluronic acid, preferably performed under ultrasound guidance, offer numerous benefits over traditional techniques, ensuring greater precision, safety, and efficacy.
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