Two Complementary Injections
ChondroFiller® and
Arthrosamid®
Both are clinic-delivered, ultrasound-guided injections, and they target different parts of the joint. ChondroFiller® coats the cartilage at the load-bearing bone surfaces; Arthrosamid® integrates into the synovial lining. Because they address different anatomical structures. A combined plan may be discussed only where assessment identifies a separate rationale for each product. Here is what each does on its own and what remains uncertain.
Reviewed byProfessor Paul YF Lee MBBch, FRCS (Tr & Orth), PhDCartilage and joint preservation expertiseQuick Answer
ChondroFiller® and Arthrosamid® work on different parts of the same joint, and they have different intended roles. ChondroFiller® coats the cartilage at the load-bearing bone surfaces and supports natural cartilage restoration over six to twelve months (£3,000 to £8,000 depending on box quantity). Arthrosamid® is a hydrogel that integrates into the synovial lining and cushions the joint from the inside. Its observational cohort reports group outcomes through 24 months, not a guaranteed duration, and current treatment starts at £3,000. A combined plan requires separate clinical justification for each component; MRI alone does not decide suitability.
The Headline Difference
ChondroFiller® vs Arthrosamid® — the key difference
ChondroFiller® is a collagen scaffold delivered onto the cartilage at the load-bearing bone surfaces, where it coats and restores the cartilage layer; the body’s own cells then migrate in and lay down new matrix over six to twelve months. Arthrosamid® is a polyacrylamide hydrogel that integrates into the synovial lining of the joint and cushions it long-term; it is mechanical, not regenerative. The two treatments target two anatomically distinct parts of the same joint. That makes a combined discussion possible, but direct evidence for the combination is limited and neither product should be added automatically.
Mechanism of Action
How each treatment works
ChondroFiller® is a sterile type I/III collagen scaffold injected as a liquid into the joint under ultrasound guidance. Within minutes it sets in place and coats the cartilage layer at the load-bearing bone surfaces, restoring the surface across the joint in a single delivery.
The patient’s own cells then migrate into the scaffold and lay down new cartilage matrix over the following six to twelve months. ChondroFiller® coats, protects and supports natural cartilage restoration; it does not mechanically cushion the joint.
Arthrosamid® is a 2.5% polyacrylamide hydrogel injected into the joint cavity under ultrasound guidance. The gel integrates into the synovial membrane and acts as a long-term cushion.
It works mechanically by cushioning and lubricating the joint. It does not regenerate cartilage, does not reverse arthritis and does not alter the joint surface.
How Long Results May Last
Duration and number of injections
Tissue formation over 6–12 months
Outcomes reported through 24 months
Direct duration comparison is misleading. ChondroFiller® coats and restores the cartilage surface across the joint; Arthrosamid® controls symptoms by cushioning the synovial lining. We measure their success differently.
Treatment Course
Number of injections
Typically one injection course, with the box quantity (one, two or three) decided from MRI: one box treats most defects up to roughly 2 cm², two or three for larger or multi-zone defects. A second course is rarely needed if the original tissue establishes.
One injection is the standard treatment course in suitable patients. A further Arthrosamid® treatment may be considered at a future date if symptoms recur and the joint is still suitable.
Safety and Infection
Safety considerations
Both are outpatient injections and both carry risks, including joint infection. London Cartilage Clinic uses ultrasound guidance, a sterile field and its documented antibiotic protocol. These precautions reduce avoidable risk but cannot eliminate infection or guarantee placement or outcome.
ChondroFiller® placement is defect-specific, so ultrasound guidance is not optional — it is the difference between filling the defect and depositing scaffold into the joint space. See Arthrosamid® infection risk and prevention for the injection-specific protocol that applies to both products.
Patient Selection
Who each treatment may suit
ChondroFiller® coats the load-bearing cartilage surface of the joint, whether the wear is a contained focal defect or diffuse across the surface. There is no upper age limit and no defect-size limit on the injection. It is delivered to the cartilage at the ends of the bones, the part of the joint where bone meets bone under load. See who is suitable for ChondroFiller?.
Arthrosamid® is for patients with established knee osteoarthritis who want long-lasting symptom relief without surgery, where an inflamed synovial lining is driving a meaningful part of the pain. See who is suitable for Arthrosamid?
Some patients may have a reason to discuss both products. Each still needs its own indication, consent and risk assessment, and direct evidence for the combined pathway is limited. Imaging is one part of that assessment rather than a treatment instruction.
Cost and Value
What each treatment costs
At London Cartilage Clinic, ChondroFiller® costs from £3,000 for one box, £5,500 for two and £8,000 for three. The box requirement is set from MRI, not by upsell. See the ChondroFiller® cost guide.
Arthrosamid® at London Cartilage Clinic is from £3,000 for one box, inclusive of consultation, ultrasound, the product, the fifteen-step injection protocol and the six-week follow-up. See the Arthrosamid® cost guide.
Both prices are all-in for the named clinician, named injection, named follow-up. The right comparison is clinical fit, not headline number.
Our Honest Take
When we may recommend each
You have cartilage wear visible on MRI, whether a contained focal defect or diffuse across the joint surface.
You want a treatment that coats and protects the cartilage at the load-bearing bone surfaces, with no upper age limit and no defect-size limit.
You want a meaningful intervention before, or instead of, considering joint replacement, including as part of a combined session with Arthrosamid® where the synovial lining is also driving symptoms.
You have established knee osteoarthritis with whole-joint symptoms.
You want long-lasting symptom relief from a cushion that integrates into the synovial lining, with realistic expectations of what an injection can and cannot do.
You want to consider non-surgical symptom management while accepting that Arthrosamid has not been proved to delay knee replacement.
When Each Is The Wrong Answer
When we would not recommend each
A single contained focal defect in an otherwise healthy joint with strong biological capacity for regeneration, where the Liquid Cartilage™ surgical regeneration pathway may be a more targeted intervention.
Untreated joint instability or major malalignment, where the mechanical problem needs to be addressed first.
Active infection or unwillingness to accept the conservative safety protocol.
A patient looking for cartilage restoration: Arthrosamid® works on the synovial lining, not the cartilage at the bone surfaces. ChondroFiller® is the right answer for that, and we can combine the two in a single session where both forms of trouble are present.
End-stage disease where joint replacement is the clinically appropriate path.
Patients expecting Arthrosamid® to regenerate cartilage; that is not what the treatment does.
The Bottom Line
In summary
ChondroFiller® and Arthrosamid® are both ultrasound-guided clinic injections, but they work on different parts of the joint. ChondroFiller® coats the cartilage at the load-bearing bone surfaces; Arthrosamid® integrates into the synovial lining. A combined plan may be discussed where each component has a separate rationale, but direct combination evidence is limited. Where the pattern of damage points to one alone, we recommend just that one. Where a surgical pathway is a better fit, we say so honestly, and the Liquid Cartilage™ pathway is one of the options we will discuss.
ChondroFiller® vs Arthrosamid®
Frequently asked questions
Can I have both ChondroFiller® and Arthrosamid® in the same session?
They can be delivered in one session where assessment supports both. The two treatments target different parts of the joint: ChondroFiller® coats the cartilage at the load-bearing bone surfaces, while Arthrosamid® integrates into the synovial lining. Because they address different anatomical structures and different clinical aims. Each needs a separate rationale and consent, and the direct evidence for using them together is limited. Imaging and examination inform the decision.
Which one regenerates cartilage?
ChondroFiller® supports natural cartilage regeneration by providing a scaffold for the body’s cells to lay down new matrix over six to twelve months. Arthrosamid® does not regenerate cartilage; it is a mechanical hydrogel cushion that integrates into the synovial membrane.
Which has more clinical evidence?
Both have published cohort data. The London Cartilage Clinic/MSK Doctors Arthrosamid® cohort included 269 patients and 314 knees with 24-month follow-up, but no randomised control group. ChondroFiller® has cartilage-specific outcome data (IKDC, Harris Hip Score, MOCART MRI) and over 19,000 cases of clinical use across joints. See the ChondroFiller® clinical evidence page.
Why is ChondroFiller® priced by boxes when Arthrosamid® is a flat fee?
A ChondroFiller® scaffold has to fill the defect; box quantity is set by defect size on MRI (one, two or three). Arthrosamid® is dosed by joint, not by defect size, so a single box covers the standard knee injection.
I have arthritis with one bad spot, which is right for me?
That is genuinely a consultation question; it should not be assumed that both are needed. ChondroFiller® addresses cartilage wear at the bone surfaces (including a focal bad spot and any wider surface wear at the same time), while Arthrosamid® is intended for symptomatic adult knee osteoarthritis. We review the MRI, history and examination and recommend only the component or pathway with a defensible rationale.
Is one safer than the other?
A simple claim that they have the same safety profile would be misleading. Both are outpatient injections and both carry infection and procedure-related risks; Arthrosamid is non-absorbable and has product-specific contraindications and antibiotic requirements. London Cartilage Clinic uses ultrasound, a sterile field and its documented antibiotic protocol, without claiming these eliminate risk.
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