Understanding Hip Joint Degeneration

The hip is a ball-and-socket joint where articular cartilage cushions the bones and allows smooth, low-friction movement. Over time, through mechanical wear, injury, or excess load, this cartilage can thin and degrade — a process most commonly described as hip osteoarthritis. The result is pain, stiffness, reduced range of movement, and difficulty with everyday activities such as walking, climbing stairs, or sitting for long periods. The severity of cartilage loss, and its location within the hip, influences which treatment options are appropriate.

Two Distinct Approaches: Injection and Surgery

At London Cartilage Clinic, patients with hip cartilage problems may be assessed for one of two pathways, depending on the nature and extent of their joint damage. It is important to understand that these are distinct procedures, not two names for the same thing.

The ChondroFiller Injection (Non-Surgical)

ChondroFiller is a CE-marked Class III medical device made by Meidrix Biomedicals in Germany. It is a cell-free type I collagen hydrogel scaffold — it contains no living cells and no hyaluronic acid. When delivered as an ultrasound-guided injection into the hip joint, the gel self-sets within approximately three to five minutes, settling over worn surfaces to provide a protective, cushioning collagen layer. It may reduce mechanical grinding and help buffer the joint environment. It recruits the patient's own progenitor cells into the scaffold, offering biological potential. The injection requires no theatre, no incision, and no general anaesthetic; it is an outpatient procedure. It is not a cure for osteoarthritis and does not reverse joint damage, but for selected patients with mild to moderate degeneration it may help ease symptoms and slow further wear. Evidence for its biomechanical behaviour in hydrogel form is described in Weizel et al. (2020, Acta Biomaterialia), and a 2023 clinical study of acellular collagen matrix injection for thumb-base osteoarthritis reported improvements in pain and function with favourable imaging findings (Corain et al., 2023, Cartilage). Hip-specific trial data remain limited; published evidence from comparable joints provides the current basis for assessment.

Liquid Cartilage — The Surgical Protocol

Liquid Cartilage is not an injection and is not a synonym for ChondroFiller. It is the Lee Liquid Cartilage Protocol (LLC Protocol) — a keyhole surgical technique developed by Professor Paul Y. F. Lee. It is performed under anaesthetic in theatre via arthroscopy, making it genuine surgery with a structured recovery period. The protocol combines the ChondroFiller scaffold with biological adjuncts: platelet-rich fibrin, platelet-rich plasma, and tranexamic acid are used at each stage to prime the defect, support scaffold anchorage, and limit early bleeding. Where the clinical picture warrants it, the patient's own mesenchymal stem cells — harvested from bone marrow aspirate concentrate (BMAC) or micro-fragmented adipose tissue (mFAT) — are added directly to the primed defect before scaffold placement, to support chondrogenesis and modulate the local inflammatory environment. Peri-operative optimisation and a phased rehabilitation programme are integral to the protocol.

Liquid Cartilage is typically considered for patients with focal cartilage defects in load-bearing joints where a non-surgical injection alone would not adequately address the depth or extent of the lesion. The hip, alongside the knee, ankle, and shoulder, is one of the joints in which this arthroscopic approach has been used. In published series of hip cartilage repair using this type of approach, modified Harris Hip Score improvements of more than 30 points have been reported, with MOCART scores — the standard MRI measure of cartilage repair tissue quality — reaching around 80 and above at follow-up. These are encouraging signals, though outcomes vary between patients and the evidence base continues to develop.

Which Pathway May Suit a Given Patient?

The ChondroFiller injection may be appropriate for patients with accessible hip lesions, early-to-moderate osteoarthritis, or those seeking a non-surgical option where joint alignment is good and disease is not advanced. The Liquid Cartilage surgical protocol tends to be considered where there is a focal, well-defined chondral defect that would benefit from precise arthroscopic preparation, biological priming, and scaffold placement under controlled surgical conditions. The decision rests on imaging findings, clinical examination, the patient's activity level and general health, and an honest discussion about what each pathway can and cannot achieve. Neither approach is suitable for advanced arthritis where bone-on-bone change is widespread; such patients are generally better served by joint replacement planning.

Evidence and Safety

The strongest published evidence for ChondroFiller as a device comes from its CE Class III registration process and from studies in accessible joints. Hip-specific data are still emerging. Side effects from the injection relate primarily to the procedure itself — transient discomfort, local swelling — and are generally mild. The arthroscopic Liquid Cartilage procedure carries the risks associated with keyhole hip surgery more broadly: infection, stiffness, anaesthetic-related effects, and the possibility that the scaffold does not integrate as intended. Neither pathway guarantees a specific outcome, and patients should receive clear, individualised information before proceeding.

Clinically reported responses to ChondroFiller injection vary between individuals and joints. Some patients describe meaningful gains in comfort and walking tolerance; others see modest benefit. The honest picture is that benefits cannot be guaranteed, larger controlled trials are needed, and this is best understood as a joint-preserving option rather than a curative one.

References

Weizel, A., Distler, T., Schneidereit, D., & Friedrich, O. (2020). Complex mechanical behavior of human articular cartilage and hydrogels for cartilage repair. Acta Biomaterialia.

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.