Introduction

If you are considering ChondroFiller, a natural question is: without stitches holding it in, how does it actually stay put? The answer lies in the material's chemistry rather than any mechanical fixation — and understanding it helps you judge whether this non-surgical option is appropriate for your joint and your circumstances.

What ChondroFiller Is

ChondroFiller is a Class III CE-marked medical device manufactured by Meidrix Biomedicals, Germany, and imported into the UK under prescription. It is an acellular (cell-free) Type I collagen hydrogel scaffold supplied as a dual-component, single-use syringe. The device is applied either as a non-surgical ultrasound-guided outpatient injection or, for larger or surgically indicated defects, arthroscopically as part of a more involved procedure. This article focuses on the non-surgical injection pathway.

The Gel-Formation Mechanism

ChondroFiller works through in-situ gelation. The two components — a purified Type I collagen solution and a neutralising buffer — are co-extruded through a mixing adapter as they are delivered. Once combined, a change in pH triggers collagen fibrillogenesis: the liquid flows to fill the exact three-dimensional shape of the worn or damaged area, then sets into a stable hydrogel within approximately three to five minutes at body temperature.

Because the material is still liquid when it enters the joint, it conforms precisely to the contours of the defect rather than resting on top of them. The resulting scaffold is self-adherent: it forms stable bonds with endogenous fibrin present in the surrounding cartilage and subchondral bone. This intrinsic adhesiveness means no sutures or external fibrin glue are required to keep it in place.

For the gelation to succeed, the defect area must be as dry as possible at the time of injection and the limb positioned so the treated surface is roughly horizontal — this prevents the collagen liquid from migrating before it sets. These are routine considerations that the injecting clinician manages.

How It Stays Stable During Movement

Once set, the hydrogel behaves as a load-absorbing matrix. It is not rigid; it deforms under joint loading and then recovers, which is consistent with the viscoelastic behaviour needed in an articulating joint. The scaffold also acts as a chemotactic stimulus, gradually recruiting the body's own progenitor cells from the surrounding synovium and subchondral bone. Over a residence time of roughly one to two years, the collagen matrix is resorbed and replaced by patient-derived repair tissue. Whether this repair tissue is hyaline-like or fibrocartilaginous varies between individuals.

What the Evidence Shows

Experience with ChondroFiller across a range of joints is encouraging, though still developing. In the knee, published series report International Knee Documentation Committee (IKDC) score improvements of approximately 30 points over 12 to 36 months. In the hip, modified Harris Hip Score (mHHS) improvements of over 30 points have been reported. MRI-based MOCART scores in knee and hip studies have reached around 80 and above, indicating good-quality defect fill and tissue integration.

For smaller or less accessible joints, a 2023 study of acellular collagen matrix injection for thumb-base (trapeziometacarpal) osteoarthritis reported improvements in pain and grip strength (Corain et al., 2023, Cartilage). Responses vary and benefits cannot be guaranteed.

ChondroFiller's safety record is well documented. Across over 19,000 units supplied since 2013, no serious device-related incidents have been reported; the overall complaint rate is very low.

The ChondroFiller Injection Versus Surgical Options

The injection pathway is suited to accessible defects and to patients for whom surgery is not appropriate or not yet indicated. It involves no theatre, no general anaesthetic, and no incision; recovery is generally straightforward compared with surgical procedures.

For larger or load-bearing defects — particularly in the knee, hip, shoulder, or ankle — a surgical approach may be more appropriate. The Liquid Cartilage procedure is LCC's keyhole surgical protocol: it delivers the ChondroFiller scaffold arthroscopically, combined with biological adjuncts such as platelet-rich fibrin or platelet-rich plasma, and where indicated the patient's own mesenchymal stem cells harvested from bone-marrow concentrate or micro-fragmented fat. This is genuine keyhole surgery involving theatre, anaesthetic, and a structured recovery programme. It is not the same as the ChondroFiller injection; the two pathways suit different clinical situations, and a specialist assessment is needed to determine which is right for a given patient.

Conclusion

ChondroFiller stays in place without stitches through a combination of in-situ gelation, precise defect-filling, and natural adhesion to surrounding tissue — not mechanical fixation. As a non-surgical injection it may support joint preservation for suitable patients, but it is not a cure and does not reverse established arthritis. Individual response varies. For an assessment that takes your joint, your activity level, and your expectations into account, a consultation with a specialist in cartilage preservation is the appropriate starting point. The London Cartilage Clinic on Harley Street offers this assessment and can advise whether the injection, the surgical Liquid Cartilage protocol, or another pathway best fits your situation.

References

Corain, M., Zanotti, F., Giardini, M., Gasperotti, L., Invernizzi, E., Biasi, V., & Lavagnolo, U. (2023). The use of an acellular collagen matrix ChondroFiller Liquid for trapeziometacarpal osteoarthritis. Cartilage.