Two injections, two different jobs

If you have been told you have a hip cartilage problem and both ChondroFiller™ and PRP have come up as options, the first thing worth knowing is that they are not competing versions of the same treatment — they do different jobs. Both are delivered as ultrasound-guided outpatient injections at Lincolnshire Hip's clinics in Grantham and Sleaford, with no general anaesthetic and no hospital stay. The question is not which is universally better, but which matches what is actually happening inside your hip joint.

ChondroFiller™ is a structural intervention. It places an acellular Type I collagen scaffold directly into the cartilage defect, giving the joint a physical 3D framework to work with. PRP (platelet-rich plasma) works differently: it is produced by centrifuging a small sample of the patient's own blood to concentrate growth factors, which are then injected intra-articularly to support the biological environment of the joint. One provides physical structure; the other provides biological signalling. Those are distinct roles, and in focal hip cartilage defects they are not interchangeable.

Neither treatment is funded routinely by the NHS. ChondroFiller™ is listed at £2,995 per injection at Lincolnshire Hip; PRP is also available at the same clinics. A consultant assessment — using MRI to map the extent and location of the damage — is needed to determine which pathway, if either, is appropriate for a given patient.

How ChondroFiller™ works in the hip

The gel sets inside the defect within minutes of injection — that rapid in-situ polymerisation is what makes ChondroFiller™ a physical intervention rather than a dissolved drug. The resulting scaffold is viscoelastic: firm enough to fill the defect space, pliable enough to move with the joint.

Because the material is acellular — containing no donor cells — it does not supply the biology needed for repair; it attracts it. Progenitor cells from the surrounding synovium and subchondral bone migrate into the collagen matrix in a process called acellular matrix-induced chondrogenesis. Over three to six months, those cells progressively remodel the scaffold into fibrocartilage-like repair tissue as the collagen is gradually resorbed. The original material is replaced by tissue generated by the patient's own biology. A 2025 ex vivo human osteochondral study measured a 2.4-fold increase in DNA content within the scaffold by day 14, providing laboratory evidence that this cell-recruitment process occurs.

In published hip clinical experience, this remodelling process has been associated with meaningful functional recovery, with improvements of approximately 30 points on the modified Harris Hip Score reported in hip applications.

The treatment is suited to isolated, focal Grade III or IV cartilage defects — typically up to 3–6 cm² on MRI — where the surrounding cartilage retains healthy borders. It is not indicated for diffuse, end-stage osteoarthritis affecting the whole joint surface. Contraindications include immunosuppression, poorly controlled diabetes, and active infection; benefits also develop gradually as repair tissue matures, making it unsuitable for patients expecting immediate pain relief.

How PRP works — and what the hip evidence actually shows

Delivered as an intra-articular injection, PRP works through biological signalling. Growth factors released by concentrated platelets — including PDGF and TGF-β — may reduce intra-articular inflammation and support the tissue environment around the joint. What PRP cannot do is fill a defect or replace lost cartilage volume: it contains no physical scaffold and provides no 3D framework for cells to repopulate.

For focal hip cartilage defects specifically, the clinical evidence is materially weaker than for some other indications. A 2022 systematic review of 1,024 hip patients found only low-quality evidence that PRP was not associated with improved outcomes following hip femoroacetabular impingement surgery — mean difference –1.42 (95% CI –3.95 to 1.11, P=.27). Those numbers, however, mostly reflect patients who also received surgery alongside PRP; available positive hip data comes from PRP's use as a surgical adjuvant — augmenting arthroscopic microfracture, for example — rather than from standalone outpatient injection into a focal cartilage defect. Evidence for that specific use case in the hip remains sparse.

PRP retains a legitimate role in the hip pathway for other presentations. At Lincolnshire Hip, it is offered primarily for groin pain and soft-tissue conditions such as tendinopathy, where biological signalling support is better matched to the underlying problem than a scaffold-based approach.

Comparing the evidence side by side

Any comparison here is cross-trial rather than head-to-head: no randomised controlled trial has directly placed ChondroFiller™ injection against PRP in hip cartilage defects. That gap reflects where the research currently stands, not a reason to defer a clinical decision. Most patients choose between options on the basis of their defect pattern, mechanistic fit, and specialist advice rather than waiting for an RCT that does not yet exist.

On current evidence, the two treatments sit at different confidence levels for this specific indication. ChondroFiller™ has laboratory confirmation of its cell-recruitment mechanism, a growing body of hip clinical use, and CE-mark Class III designation as a medical device. What it does not yet have — and what should be said plainly — is long-term randomised trial data for the injectable delivery route. The injection form is newer than the earlier arthroscopic version, and the evidence base for it is still accumulating; that is a transparency point rather than a disqualifying one.

PRP has a well-established safety profile and stronger evidence in other joint indications. For focal hip cartilage defects as a standalone outpatient injection, the confidence level is lower, with available hip data coming largely from surgical rather than injection settings.

Where the two treatments most clearly differ is in how closely their existing evidence maps to the specific combination of hip joint, focal defect, and outpatient injection — which is what most patients reading this are considering.

Which treatment fits which patient

Deciding between the two comes down to what your MRI shows and where you are in the hip pain pathway.

If imaging confirms a focal cartilage defect — the kind of well-contained, Grade III or IV lesion described above — ChondroFiller™ is the mechanistically better-matched option: a scaffold injected precisely where the defect sits. Diffuse degeneration across the whole joint falls outside its indicated range, as does any defect substantially larger than 3–6 cm²; so do patients with active infection, immunosuppression, or poorly controlled diabetes, who require individual clinical review before either treatment is considered.

If hip pain is dominated by inflammation, soft-tissue involvement, or tendon-related groin symptoms — and structural cartilage loss has not yet been confirmed or remains mild — PRP is the more appropriate starting point. Its biological signalling mechanism is a better fit when the dominant problem is the joint environment rather than a discrete structural gap in the cartilage surface.

A stepped approach is clinically rational for many patients: PRP as a lower-intervention first step where pain and inflammation are the presenting problem; ChondroFiller™ once a focal defect is confirmed and the defect pattern is clearly established. These are not competing options at the same decision point — they often sit at different stages of the same pathway.

Neither should be chosen without MRI assessment and a clinical review. Defect size, location, surrounding cartilage health, and individual contraindications all shape which treatment — if either — is the right fit.

What a Lincolnshire Hip appointment looks like

Appointments for both treatments take place at Lincolnshire Hip's clinics in Grantham or Sleaford, with Professor Lee reviewing your existing imaging before or at the point of assessment.

ChondroFiller™ is delivered under local anaesthetic as an ultrasound-guided injection placed directly into the hip joint — the appointment typically runs 30–60 minutes. MRI is required beforehand to confirm defect size and that the surrounding cartilage is in suitable condition to support the scaffold. Partial weight-bearing is usually the position at around six weeks, with a return to higher-impact activity at approximately 12 months alongside specialist rehabilitation guidance. The guide price is £2,995 per injection.

PRP involves a blood draw and centrifugation at the same visit, followed by intra-articular injection. Recovery is generally quicker, with fewer activity restrictions — though the specifics depend on which tissue is being targeted and are discussed at consultation. PRP pricing is confirmed at the time of assessment.

Neither treatment is currently NHS-funded for hip cartilage indications, so both are accessed privately, and no GP referral is needed. Lincolnshire Hip is part of the MSK Doctors group and accepts patients directly — meaning the step from suspecting a cartilage problem to having a specialist review your imaging and map a structured treatment plan can be considerably shorter than many patients expect.

1. [1] PRP Is Not Associated With Improved Outcomes Following Hip Femoroacetabular Impingement Surgery — Systematic Review. (2022). https://doi.org/10.1016/j.asmr.2022.05.002 https://doi.org/10.1016/j.asmr.2022.05.002
2. [2] Patients Undergoing Microfracture With Allograft Cartilage and autologous PRP Augmentation For Chondromalacia In The Hip — 2-Year Follow-Up. (2025). https://doi.org/10.1016/j.arthro.2025.01.022 https://doi.org/10.1016/j.arthro.2025.01.022