Two treatments, one deciding factor

Most patients researching ChondroFiller and Arthrosamid arrive with the same question: which one is better for my hip? The honest answer is that framing misses the point. These two treatments occupy different positions in the hip cartilage pathway — they are not competing for the same patient.

The deciding factor is the stage and pattern of cartilage damage, not price or brand preference. ChondroFiller is an injectable collagen scaffold suited to focal, contained defects in a hip joint that is otherwise relatively preserved — broadly, Tönnis Grade 0–1 disease with a defined area of Grade III or IV cartilage loss. Its mechanism is regenerative: the scaffold recruits the patient's own progenitor cells to support repair of that specific defect. Arthrosamid is a permanent polyacrylamide hydrogel designed for a different problem entirely — diffuse cartilage loss with moderate-to-advanced hip osteoarthritis, where the clinical goal is sustained pain relief and delaying hip replacement rather than tissue repair.

Both treatments are delivered as outpatient, ultrasound-guided hip injections under local anaesthesia. Neither is surgery. What separates them is what a hip MRI or clinical assessment reveals about the extent and pattern of cartilage damage — and that assessment, rather than personal preference, is what determines which pathway is appropriate.

The sections below explain how each treatment works, what the published evidence shows, and how that translates into practical patient selection.

ChondroFiller: a scaffold for focal hip cartilage defects

Inside the hip joint, ChondroFiller behaves like liquid that becomes solid. The product — an acellular Type I collagen hydrogel manufactured by Meidrix Biomedicals GmbH and CE-marked as a Class III medical device — arrives as a two-chamber syringe. Once mixed and placed into the joint under ultrasound guidance, it self-sets within approximately 3–5 minutes, conforming precisely to the shape of the defect and forming a dimensionally stable three-dimensional scaffold.

The biological process that follows is called acellular matrix-induced chondrogenesis. The collagen matrix acts as a chemotactic signal, drawing the patient's own progenitor cells — from the surrounding synovium and subchondral bone — into the scaffold, where they can attempt repair. There are no donor cells, no biopsy, and no general anaesthesia; the procedure is an outpatient, ultrasound-guided injection under local anaesthesia, and patients leave the same day.

Patient selection is the critical variable. ChondroFiller is designed for isolated focal Grade III or IV cartilage defects, typically up to approximately 2.5 cm², in a hip joint with healthy surrounding borders and no significant background osteoarthritis. Published hip cohort data illustrate the boundary clearly: in a prospective study of 26 patients with femoroacetabular impingement and acetabular cartilage lesions treated with ChondroFiller, 17 of 21 evaluable patients achieved good or excellent results at three to five years — but those with pre-existing Tönnis Grade 2–3 osteoarthritis did poorly. When diffuse joint degeneration is already present, the scaffold has no healthy environment in which to work.

Expectations around timing matter too. Healing is gradual — published timelines indicate 6–24 months for new tissue formation — and the regenerated tissue may not match native cartilage in mechanical strength. Most of the detailed outcome data originate from knee studies; hip-specific evidence, while promising, remains more limited, and no large-scale randomised controlled trial in the hip has yet been completed.

Arthrosamid: a lasting cushion for moderate-to-advanced hip OA

Where ChondroFiller works by providing something new — a scaffold to recruit repair — Arthrosamid works by changing the mechanical environment of a joint that has already lost significant cartilage. The hydrogel is injected directly into the hip joint under ultrasound guidance in a single outpatient session lasting approximately 30 minutes. Once inside, it integrates permanently with the synovial lining and acts as a lasting viscoelastic cushion, redistributing load across the hip and reducing the friction that accompanies cartilage loss. It is not absorbed or broken down by the body.

This is not a regenerative therapy. Arthrosamid does not repair, rebuild, or recruit cells to restore articular cartilage; its role is mechanical load distribution and sustained symptom relief. Patients considering it at the hip should understand two things before proceeding. First, it is licensed in the UK for knee osteoarthritis and used off-label for hip disease — a distinction clinicians are obliged to explain at consent. Second, that off-label status reflects an evidence gap rather than a safety concern: no long-lasting adverse events were recorded across a systematic review of 463 patients, which confirmed statistically significant improvements at 52 weeks and 13 months, sustained at two years, with results numerically superior to hyaluronic acid in a randomised trial. The primary evidence base is for the knee; direct hip-specific data, while supportive, are more limited.

Two contraindications narrow the patient group clearly. End-stage hip arthritis — where bone contacts bone directly and joint space is effectively absent — falls outside Arthrosamid's range, as does active infection in or near the hip. Patients seeking cartilage restoration rather than symptom management are equally unsuited; the goal here is buying a meaningful period of comfortable function, not reversing tissue damage.

How the two injections compare in practice

Both injections cost approximately £2,800–£3,000 for a hip treatment and are self-funded private procedures — neither is available on the NHS. On price alone, they sit in the same bracket, which means cost is unlikely to be the deciding factor for most patients.

The more meaningful practical difference is when you are likely to notice something. Arthrosamid, as a hydrogel that physically integrates into the synovial lining, tends to produce noticeable relief within weeks as the material settles. ChondroFiller's improvement is biological in nature — the scaffold recruits cells that attempt repair — so the timeline is considerably longer: published data indicate that meaningful tissue remodelling unfolds over months, with the full effect taking anywhere from six months to two years. Neither timetable is evidence of superiority; they simply reflect different mechanisms.

Permanence is the other distinction worth naming plainly. Arthrosamid is not absorbed or broken down; once integrated, it remains. The ChondroFiller collagen scaffold is gradually replaced over time as recruited cells lay down new tissue — the scaffold is the temporary structure, not the end result.

In terms of the appointment itself, both are single outpatient injection sessions guided by ultrasound under local anaesthesia. A consultation and pre-injection imaging review are part of the pathway for each. Post-injection, mild soreness for a few days is typical for both, and most patients return to everyday activities within a short period.

Lincolnshire Hip is part of the MSK Doctors group and accepts patients without referral for hip assessment.

What the evidence actually shows — and where gaps remain

No randomised controlled trial has yet compared ChondroFiller and Arthrosamid directly in the hip — a point worth stating plainly, because it means every clinical decision currently rests on indication-matching and disease-stage reasoning rather than head-to-head outcome data.

For ChondroFiller, the most recent hip-specific evidence comes from two distinct sources. A 2025 case report describes a 32-year-old man with a 15 mm × 5 mm osteochondral lesion on the weight-bearing dome of the femoral head; treated with ChondroFiller placed at arthroscopy without microfracture, he achieved complete pain relief, full hip range of motion, and normal gait post-operatively. A 2023 study in 44 patients with Kellgren-Lawrence Grade I–II hip osteoarthritis found that ultrasound-guided collagen-based injection produced significant improvements in VAS pain and WOMAC scores at one month, with further gains at three months, compared with no meaningful improvement in the NSAID comparator group; no adverse events were recorded in either group. The injectable delivery route — the pathway used in the current clinic setting — represents a newer application than arthroscopic placement, and the independent hip injection evidence base is still accumulating.

For Arthrosamid, the formal evidence base remains predominantly knee-derived. Hip-specific published data are more limited, which is why NHS commissioning bodies have not yet approved it for routine hip use. That gap is an evidence question, not a safety signal — but it does mean patients and clinicians are drawing on extrapolated rather than directly hip-applicable outcome data.

The clearest takeaway is that neither treatment has a mature, hip-specific randomised controlled trial record. Both are supported by emerging but not yet definitive hip data, alongside stronger evidence from adjacent joints and applications.

Getting assessed and accessing treatment in Lincolnshire

For patients in Lincolnshire and the wider non-London catchment, the practical first step is the same regardless of which pathway turns out to be appropriate: an MRI of the hip joint. Imaging establishes OA grade, defect size, and the condition of the surrounding cartilage — without it, neither treatment decision can be responsibly made, because the scan is what distinguishes a focal containable defect from diffuse wear across the joint surface.

Arthrosamid for hip osteoarthritis is available locally through Lincolnshire Hip at clinics in Grantham and Sleaford. No GP referral is needed to book an initial assessment appointment. ChondroFiller for hip cartilage defects is offered through specialist UK centres; if your imaging suggests a focal defect profile, an assessment will clarify whether the size, grade, and surrounding joint health place you within the indication.

Typical candidates for either pathway are patients who have worked through physiotherapy, lifestyle adjustment, and analgesics without finding lasting relief, and who want a longer-term option short of hip replacement.

The most useful things to bring to that first appointment are your most recent hip MRI, a clear account of when symptoms began and how they have changed, and a realistic sense of your activity goals. Those three things — imaging, symptom timeline, and functional ambition — are what shape the treatment conversation. They determine not just which injection may be appropriate, but whether the expected recovery timeline and degree of improvement are likely to match what you are actually hoping for.

1. [1] Arthroscopic utilization of ChondroFiller gel for the treatment of hip articular cartilage defects: a cohort study with 12- to 60-month follow-up. (2021). https://doi.org/10.1093/jhps/hnab002 https://doi.org/10.1093/jhps/hnab002
2. [2] A Systematic Review of the Novel Compound Arthrosamid Polyacrylamide (PAAG) Hydrogel for Treatment of Knee Osteoarthritis. (2022). https://doi.org/10.18103/mra.v10i8.2950 https://doi.org/10.18103/mra.v10i8.2950
3. [3] Ultrasound guided injection with Collagen-based Medical Device: real-life evaluation of efficacy and safety in hip osteoarthritis. (2023). https://doi.org/10.11152/mu-4242 https://doi.org/10.11152/mu-4242
4. [4] Hip Arthroscopy and Chondrofiller Application in Isolated Osteochondral Defect of the Femoral Head. (2025). https://doi.org/10.13107/jocr.2025.v15.i10.6176 https://doi.org/10.13107/jocr.2025.v15.i10.6176