One device, two names — what that means for you

If you have seen both names and wondered which one to ask about, the short answer is that ChondroFiller® and Liquid Cartilage™ are not two competing products — one is the underlying medical device and the other is a procedure label built on top of it.

ChondroFiller® is an acellular Type I collagen scaffold manufactured by Meidrix Biomedicals GmbH in Germany. It holds a CE mark as a Class III medical device — the highest regulatory category for implantable devices in Europe — and works by forming a gel at body temperature that bonds to the walls of a cartilage defect and recruits the patient's own progenitor cells to support repair from within.

Liquid Cartilage™ is a trademarked procedure name applied to a specific clinical application of that same ChondroFiller scaffold, augmented with the patient's own medicinal signalling cells (MSCs) harvested from bone marrow, adipose tissue, or platelet-rich fibrin and co-delivered in the same appointment. The scaffold is the common thread; what varies between the two names is the clinical setting, the degree of biological augmentation, and which patients each pathway is suited to.

Readers comparing the two by name are, in effect, comparing a product to a named procedure built on that product — not two independent technologies. That distinction shapes every practical question that follows: who is assessed, how the treatment is delivered, and what the evidence supports.

How the ChondroFiller scaffold works inside the joint

Delivered as a liquid collagen solution through an ultrasound-guided outpatient injection, ChondroFiller® undergoes a physical change the moment it meets body temperature: within minutes it self-sets into a stable gel that conforms to the shape of the cartilage defect and adheres directly to its walls. Think of it as a temporary framework — not a permanent patch — that holds space while the body's own biology does the restorative work.

The scaffold contains no donor cells of any kind. Instead, it is designed to act as a chemotactic signal, drawing the patient's own mesenchymal progenitor cells out of the surrounding synovial fluid and subchondral bone into the gel matrix. Once those cells have colonised the scaffold, they begin depositing collagen and glycosaminoglycans — the structural proteins found in healthy cartilage. Over 12 to 24 months the scaffold is naturally resorbed, gradually replaced by hyaline-like tissue. This process is sometimes described as acellular matrix-induced chondrogenesis: the scaffold supports the body's own chondral repair processes rather than providing the cells itself.

When concentrated biological support is added — as in the combined-cell procedure assessed by specialist clinicians — the same scaffold mechanism may be amplified. A 2025 ex vivo study using osteochondral explants found a 2.4-fold increase in DNA content within ChondroFiller-treated tissue by day 14, confirming active cell recruitment; co-delivery of additional cells produced further gains in both collagen deposition and glycosaminoglycan production. That finding comes from a laboratory model, not a clinical trial, so its translation to patient outcomes requires cautious interpretation.

Which patients are assessed for ChondroFiller treatment

Three questions tend to determine whether a patient is a realistic candidate: what type of cartilage damage is present, how healthy is the surrounding joint tissue, and does the defect pattern fall within the range where the scaffold can recruit enough of the body's own repair cells to be effective?

The core candidate profile

The strongest candidates have a focal cartilage defect — a discrete, contained area of damage rather than widespread thinning across the whole joint surface. Clinically, these are graded using the ICRS scale (International Cartilage Repair Society), which runs from Grade I (surface softening) to Grade IV (full-thickness loss down to bone). ChondroFiller is typically assessed for Grade III to Grade IV lesions: damage deep enough to warrant active treatment but surrounded by cartilage that is still structurally sound. Preserved subchondral bone (the bone layer beneath the cartilage) and healthy borders around the defect are both important, because the scaffold relies on adjacent tissue for biological support during the repair phase.

Age is not a fixed barrier for the injectable pathway; defect pattern, bone quality, and confirmed regenerative capacity carry more weight in the assessment than a patient's age alone.

Who is not suitable

The clearest exclusion is diffuse bone-on-bone arthritis — classified as Tönnis grade 2–3 in the hip or Kellgren–Lawrence grade III–IV in the knee. A 2021 hip cohort study (Mazek, 26 patients, 12–60 months follow-up) documented poor outcomes specifically in patients with pre-existing Tönnis grade 2–3 disease, establishing advanced generalised osteoarthritis as a confirmed contraindication. The treatment is designed to support focal repair, not reverse widespread joint degeneration.

How pathway is determined

Whether the injectable pathway alone is appropriate, or whether additional biological support is clinically indicated, is determined by specialist assessment — not self-selected by the patient. Larger or biologically complex defects may be reviewed for a combined approach; that assessment considers defect geometry, joint loading, and overall cartilage health.

What clinical studies show about outcomes

Published evidence for ChondroFiller® spans several joints and study designs, though most individual cohorts are small and should be read as feasibility data rather than definitive proof.

The earliest controlled comparison is a 2016 prospective multicentre randomised study of 23 patients — 13 treated with ChondroFiller and 10 with microfracture. IKDC scores in the ChondroFiller group improved significantly from baseline at three, six, and twelve months, with MRI confirming good immediate defect filling and progressive cartilage maturation over time. No adverse events were recorded in that study.

Hip data comes from a 2021 cohort (Mazek, 26 patients, 12–60 months follow-up): 17 of 21 assessable patients achieved good or excellent results at three to five years, with significant improvement confirmed on MRI cartilage healing assessment. Those with advanced pre-existing osteoarthritis fared poorly — reinforcing the selection criteria described in the section above.

A 2024 knee series of 17 patients reported significant gains on both the Lysholm score and IKDC, with results stabilising between six and twelve months — consistent with the improvement window seen in the earlier RCT data. A 2025 feasibility study in the wrist confirmed superior Outerbridge and ICRS cartilage scores at follow-up assessment. That study used a surgical delivery route; it should not be read as a description of the ultrasound-guided outpatient injection pathway.

The manufacturer's April 2025 Clinical Evaluation Report synthesises available data into a benchmark of approximately 30 IKDC points of improvement over 12 months — broadly comparable to two-stage ACI or MACI, but achieved in a single stage. The reported complication rate is close to 0%, with reoperation at approximately 3–8%, against microfracture's reported reoperation rate of up to 41%.

One gap the evidence does not yet fill: published data relates to ChondroFiller® as a product. The Liquid Cartilage™ procedure name — which pairs the scaffold with a patient's own concentrated cells in a single visit — does not yet have independent peer-reviewed cohort data separate from the broader ChondroFiller literature. Patients weighing either pathway should raise this distinction directly with their assessing clinician.

Recovery timeline and what to ask your specialist

The most immediately practical finding from laboratory research is that the scaffold takes time to stabilise before it can safely bear full joint load. A 2024 in-vitro friction study showed ChondroFiller in its early phase did not meaningfully reduce damage to opposing cartilage under cyclic loading — an outcome attributed to the initial mechanical instability of the gel. Weight-bearing is therefore delayed until stable integration is confirmed; your treating specialist will build that phasing into the rehabilitation plan from the outset.

On current knee series data, symptom improvement tends to stabilise between six and twelve months after the injection. Because the injectable outpatient pathway does not involve surgical incisions, theatre admission, or general anaesthesia, the recovery burden is generally lighter than for open or arthroscopic surgical alternatives — though a structured rehabilitation programme still applies.

Questions worth raising at your consultation

• What ICRS grade is my defect, and are the surrounding cartilage borders healthy?
• Based on my imaging, am I a candidate for the injectable pathway as it stands?
• What does the weight-bearing and rehabilitation schedule look like for my specific defect size and location?
• If a combined scaffold-and-cell approach is being discussed, what case series or outcome data underpins that specific recommendation for me?

That last question is worth raising clearly. Personal clinical experience may sit alongside the published product literature as the primary reference for certain combined approaches, and most experienced specialists are well-placed to walk through their own outcomes data at consultation.

How to find a specialist for ChondroFiller treatment

The evidence currently available supports ChondroFiller® as a single-stage injectable scaffold approach for focal cartilage defects in appropriately selected patients — with outcomes that broadly match more complex two-stage procedures but without the surgical burden. What the literature does not yet provide is large-scale trial data or independent published series for the combined scaffold-and-cell technique. That distinction is worth naming at a first consultation, alongside the questions about defect grade, border health, and rehabilitation phasing that determine whether the injectable pathway is appropriate for a given joint.

Finding a specialist with experience in cartilage assessment and image-guided scaffold injection is the practical next step. Search MSK lists clinicians across the UK who offer ChondroFiller injection and related cartilage treatments, with filters by region and specialty to help identify someone suited to your clinical situation.