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Everything You Need to Know About Hyaluronic Acid Injections for Knee Osteoarthritis

Treatments for Knee Osteoarthritis

Knee osteoarthritis (OA) is a degenerative joint disease that millions grapple with daily. It manifests as pain, stiffness, and reduced joint mobility. A diverse range of treatments have been employed over the years, from non-invasive methods like physiotherapy, pain medications, orthotics and joint injections, to surgical options. Within this spectrum, the utilisation of Hyaluronic acid injections has gained considerable attention for its efficacy and non-surgical nature.

woman with knee pain

What is Hyaluronic Acid and How Does it Work in Knee Osteoarthritis ?

Hyaluronic acid (HA) is a gel-like substance naturally present in the synovial fluid of our joints. Its primary functions are to lubricate the joint surfaces and act as a shock absorber. When osteoarthritis develops, the concentration of this critical component reduces, leading to increased joint friction, pain, and inflammation. Administering external HA aims to rejuvenate these innate properties.

These injections supplement the knee's diminished synovial fluid. When HA is introduced into the affected joint, it serves to enhance lubrication, reduce friction between joint surfaces, and potentially stimulate the production of natural HA. Cumulatively, these effects facilitate smoother joint movements and a potential reduction in pain.

Hyaluronic Acid Injection Imaginary

Who Can Get Hyaluronic Acid Injections for Knee Osteoarthritis?

HA injections are becoming an increasingly popular treatment for individuals suffering from knee osteoarthritis. But while they can offer significant benefits, they're not suitable for everyone. Here's a more in-depth look at the ideal candidates:

Severity of Osteoarthritis:

Mild to Moderate OA: Those with early to mid-stage osteoarthritis tend to benefit the most. The injections can replenish the diminishing HA in the joint, reducing friction and pain.

Advanced OA: Individuals with severe degeneration may find limited benefit, as the structural damage in the joint may be beyond the reparative capabilities of the injections.

right knee xray

Previous Treatments:

Patients who have tried and found minimal relief from first-line treatments, such as weight management, physiotherapy, exercise, and over-the-counter pain medications, often consider HA injections as a next step before contemplating surgical options.

Age Considerations:

While osteoarthritis is more common in older adults, younger individuals with early onset of OA or joint injuries might also be candidates. It's essential to evaluate each case individually, weighing the potential benefits against any risks.

Medical History:

Patients should not have any active infections or skin diseases in or around the knee joint. Moreover, those allergic to avian products need to exercise caution as some HA preparations are derived from rooster combs.

Patient Preferences:

Some individuals prefer HA injections over other treatments because they are perceived as more natural. As HA is a substance naturally found in the body, it can appeal to those seeking treatments that align closely with the body's biology.

Cost and Accessibility:

HA injections might not be readily available everywhere and can be more costly than some other treatments. Patients should consider their financial situation, insurance coverage, and accessibility when evaluating this treatment option.

doctor riding syringe

When Are Hyaluronic Acid Injections Not Appropriate?

Though advantageous, these injections are not universal panaceas. Patients with severe OA, existing infections in or near the knee, or known allergies, especially to avian-derived products (since some preparations of HA originate from rooster combs), should explore other therapeutic avenues.

Do Hyaluronic Acid Injections Work for Knee Osteoarthritis?

Extensive clinical research supports the efficacy of HA injections in managing OA symptoms. Most patients report a significant dip in pain and improved joint function post-treatment. Nonetheless, individual responses can vary, emphasizing the importance of personalized care and consultations. (see references below).

Getting a Hyaluronic Acid Injection: What to Expect

The treatment entails a direct injection of HA into the knee joint. After going through a detailed clinical and radiological assessment of the knee, the doctor will go through a formal consenting process where details of all appropriate treatment options are explained. If the patient opts for HA injection, the doctor will prepare the knee for injection with an antiseptic solution or wipe.

The injection is then performed with or without ultrasound guidance. Most sessions conclude within a few minutes, followed by a short observation period. Following the injection, patients are advised and encourages to mobilise as normal but avoid strenuous activities like running for a couple of weeks.

doctor holding filled syringe

How Long Do Hyaluronic Acid Injections Last?

Though variable, the therapeutic effects of hyaluronic injections often last between 6 to 12 months, or longer in some patients. Patient activity levels, severity of OA, and individual physiological responses can influence the duration of relief.

Are There Any Side Effects?

Potential side effects can emerge post-procedure. Common ones encompass pain, swelling, or redness at the injection site. However, these typically wane within a few days. Infrequent side effects can entail allergic reactions or infections, necessitating prompt medical attention. However, the safety profile of HA is considerably better when compared to other knee injections.

happy man following knee injection

Comparison: Hyaluronic Acid, Steroid, and PRP Injections

When it comes to non-surgical interventions for knee osteoarthritis, three prominent treatments emerge: HA, steroid, and platelet-rich plasma (PRP) injections. A brief comparative analysis illuminates the distinct advantages and drawbacks of each.


  • HA: Restores lubrication, reduces friction, and potentially stimulates the natural production of HA, leading to smoother joint movement and decreased pain.

  • Steroid: Provides rapid pain relief by reducing inflammation. However, its efficacy can taper off quickly for some individuals.

  • PRP: Utilises growth factors in the patient's blood to potentially promote healing. Its effectiveness is still being thoroughly researched, but initial results show promise.

Duration of Pain Relief:

  • HA: Offers sustained pain relief, usually lasting between 6 to 12 months, depending on individual factors.

  • Steroid: While initial relief is rapid, it's often short-lived, spanning a few weeks to months. Repeated injections might lead to diminishing returns.

  • PRP: Duration is variable, ranging from months to over a year, depending on the specific preparation and individual response.

Safety Profile:

  • HA: Generally well-tolerated with mild side effects, such as pain or swelling at the injection site. Rare allergic reactions or infections can occur.

  • Steroid: Repeated injections can lead to joint damage or other side effects, including elevated blood sugar or systemic effects.

  • PRP: Being autologous (derived from the patient), PRP has a favourable safety profile with minimal risk of allergic reactions. However, as with any injection, there's a slight risk of infection.

Are Hyaluronic Injections an Alternative to Knee Surgery?

For a subset of patients, hyaluronic injections can indeed serve as an alternative or a delay to surgical intervention. However, as a progressive condition, osteoarthritis may reach a stage where injections lose their efficacy, directing patients toward surgical considerations.

Both therapeutic routes offer benefits. HA injections are less intrusive, have swifter recovery periods, and can be recurrently administered. In contrast, surgical measures, such as knee replacements, might offer more long-standing relief but come with inherent surgical risks and recuperation timelines.


Knee osteoarthritis is a condition that affects a substantial portion of the population worldwide, impacting daily activities and overall quality of life. With advancements in medical technology and knowledge, treatments like HA injections have provided hope and relief to many. As with all medical interventions, patient education, and individual assessment are paramount.

If you or someone you know is grappling with knee pain, considering options, or seeking a comprehensive evaluation, don't hesitate. Book an appointment at ACTIVATE Musculoskeletal Clinic in Kent for a thorough assessment of knee pain and potential HA knee injections. Your journey towards a pain-free life could just be an appointment away. You can also check which knee injection may be suitable for you using ACTIVATE's free digital tool.

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About the Author: Dr. Mustafa Alnaib MBChB, MRCS, MSc, FEBOT is an orthopaedic surgeon, musculoskeletal doctor and Clinic Director at ACTIVATE Musculoskeletal Clinic in Kent


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