Which type of surgeon should you see first?

The answer depends largely on the size and severity of the defect — but the threshold for seeking a cartilage subspecialist is lower than most patients expect.

For small, incidental, or low-grade cartilage changes discovered incidentally on a scan, a general orthopaedic surgeon can provide a competent initial assessment and may manage the condition appropriately, particularly if symptoms are mild. That said, even at this stage, a specialist opinion adds value — cartilage defects larger than roughly 1 cm² tend to worsen rather than stabilise, and the window for joint-preserving treatment narrows over time.

For symptomatic defects of roughly 2 cm² or more, for active patients where cell-based repair or osteochondral grafting might be needed, or for any case where the full range of modern techniques should be considered, a cartilage subspecialist is the more appropriate first choice — not a referral destination after an initial consultation elsewhere. The treatment options available at specialist cartilage centres far exceed what most general orthopaedic surgeons routinely offer, from microdrilling and mosaicplasty through to MACI, osteochondral allografts, and injectable collagen scaffolds.

The practical cost of an ill-matched first consultation is not simply a delay. Some earlier interventions — particularly traditional microfracture — can damage the subchondral bone plate and narrow the options available for any subsequent repair. Getting the decision right first time matters.

Access is more straightforward than many patients assume. Most UK cartilage specialists accept self-referrals and work within major private insurance networks, so a GP letter is not always a prerequisite for a specialist assessment.

The treatment options a cartilage specialist brings to the table

The gap between what a generalist and a specialist can actually offer becomes clear when you map the available procedures from simplest to most complex.

Most general orthopaedic surgeons work at the lower end of this ladder. Chondroplasty — arthroscopic smoothing of damaged cartilage — addresses symptoms without restoring any tissue. Traditional microfracture, the next step up, punctures the bone beneath the defect to stimulate a repair response, but the tissue it produces is fibrocartilage: structurally inferior to native hyaline cartilage and prone to breaking down within two to three years. Specialist practice has largely moved on from microfracture; where marrow stimulation is still appropriate, microdrilling has replaced it in many specialist centres. A 2025 head-to-head study found microdrilling produced significantly better MOCART scores and IKDC functional outcomes than traditional microfracture — a distinction that rarely filters down to general orthopaedic practice.

Cartilage specialists can offer the full repair ladder above this:

• Single-stage options — AMIC (microfracture augmented with a supportive scaffold that improves the quality of repair tissue); OATS or mosaicplasty (plugs of bone and cartilage taken from a low-load area of the patient's own knee and fitted into the defect); and ChondroFiller injection, an ultrasound-guided outpatient procedure that delivers an injectable collagen scaffold directly into the defect, where the body's own progenitor cells migrate in and build new cartilage
• Two-stage cell-based procedures — ACI and MACI, in which cartilage cells are harvested from the patient, multiplied in a laboratory over several weeks, and re-implanted on a collagen membrane at a second operation
• Bulk osteochondral allograft (OCA) — transplanting a fresh donor graft to fill large or post-traumatic defects where the patient's own tissue is insufficient

ICRS accreditation, NJR registration, and BASK membership are practical markers that a centre routinely operates across this range. Patients comparing surgeons across the UK can use these credentials as a starting filter when assessing whether a given specialist is equipped to consider every option appropriate to their defect.

How defect size changes who you need to see

Defect size is the single most reliable guide to which procedures — and therefore which surgeon — are genuinely available to you.

For lesions below roughly 2 cm², marrow stimulation or mosaicplasty (OATS) are considered defensible by current evidence. A general orthopaedic surgeon with appropriate training may manage defects in this range adequately, and outcomes at this scale are broadly comparable across techniques. Even so, these thresholds are approximate: size is one variable among several, and individual anatomy, activity level, and the condition of surrounding tissue all feed into the final decision.

Once a defect reaches around 3 cm² or above, the algorithm shifts meaningfully. The SUMMIT trial demonstrated that MACI is superior to microfracture at both two and five years for defects of this size. A surgeon who cannot offer MACI is not simply choosing a different technique — they are structurally unable to deliver what the evidence currently supports for medium-to-large defects. At this threshold, a cartilage specialist is not a referral of last resort; it is the appropriate first port of call.

For very large or post-traumatic lesions where the patient's own tissue cannot fill the defect, bulk fresh osteochondral allograft (OCA) is the intervention of choice. In a 244-patient cohort with a mean age of 37.8 years, OCA achieved graft survivorship of 86.6% at five years and 73.3% at ten years — outcomes firmly anchored to high-volume specialist practice.

Accurate sizing requires MRI, not clinical estimation. Precise measurement on imaging is the prerequisite for any of these decisions, which means that even patients who are uncertain about their next step benefit from an early specialist scan review before a treatment pathway is fixed.

Alignment, joint health, and the assessment only a specialist routinely does

A cartilage repair carried out in a malaligned knee is far more likely to fail — and the numbers make the case plainly. A systematic review of 1,747 patients found reoperation rates of 47.4% when cartilage repair was performed without correcting underlying malalignment, against 17.3% when a corrective osteotomy (HTO or DFO) was carried out at the same time. That is not a marginal difference; it represents more than a halving of the probability of needing further surgery.

The state of the surrounding joint matters equally. A 2019 study identified Kellgren-Lawrence grade ≥3 radiographic change and meniscus volume loss below 50% as independent predictors of osteochondral graft failure, with measurably worse postoperative IKDC and KOS-ADL scores in patients who met either threshold. These are the benchmarks a cartilage specialist applies routinely at the pre-operative stage — not to exclude patients from surgery, but to counsel them accurately on risk and to decide whether alignment correction should form part of the same operative plan.

A general orthopaedic surgeon may be fully capable of performing either a cartilage procedure or an osteotomy individually. What may not follow is the routine integration of both — the habit of treating alignment, meniscal status, and cartilage lesion as inseparable variables rather than distinct problems to be addressed separately or sequentially.

Before committing to any surgical plan, patients are well served by asking directly: "Will you assess my alignment and meniscal health as part of this plan, and address them if needed?" The comprehensiveness of that answer reveals a great deal about how thoroughly the case is being managed.

Why the right diagnosis needs the right imaging

Standard MRI is reliable for detecting cartilage loss, but it does not tell the full story. A conventional scan can confirm that cartilage has thinned or is absent, yet leave the biochemical state of the surrounding tissue largely uncharacterised. This gap matters in practice: cartilage that looks intact on a standard scan may already be showing early collagen breakdown — a change that compositional sequences such as T2 mapping and dGEMRIC can reveal. That distinction can shift the clinical plan from monitoring to active repair, which is a meaningful difference in how a specialist approaches the case.

Accurate ICRS or Outerbridge grading and a precise measurement of lesion size are prerequisites for selecting between procedure options. A report that notes only "cartilage thinning" is not detailed enough to anchor a treatment decision. Specialist centres tend to have access to cartilage-specific MRI protocols and radiologists experienced in reporting them; patients presenting with a standard community scan may be advised to have a repeat study using a dedicated cartilage protocol before a procedure is agreed.

Two practical steps help make a first specialist appointment more productive: bring any existing scans and ask at the outset whether further imaging — including compositional sequences — is warranted before a treatment pathway is fixed.

What to expect from a specialist referral, and how to find one

Cartilage repair is joint-preserving surgery, not a cure. Even the most technically demanding procedure — a cell-based graft or a fresh osteochondral allograft — aims to delay rather than eliminate the possibility of future intervention; a specialist who communicates that honestly from the outset is a better long-term partner than one who overpromises.

Before the first appointment. UK private insurers — including Bupa, Aviva, and WPA — cover advanced cartilage procedures under CCSD codes W3111 and W8500, but almost all require written pre-authorisation before treatment begins. Seeking that approval before attending the specialist appointment, rather than after a plan has been agreed, avoids delays and clarifies the financial scope early.

What a useful first consultation covers. A specialist appointment should produce four things: a graded assessment of lesion size and location; an evaluation of alignment and meniscal health as variables that affect the repair plan; a structured account of which procedures the surgeon can actually offer and what their evidence profiles show; and a candid discussion of what 'success' means at two, five, and ten years — not just in the immediate postoperative period.

Finding the right surgeon. Beyond the accreditations covered earlier in this article, one practical question to ask any potential surgeon is how many cartilage procedures they perform in a typical year. Volume is an imperfect but useful proxy for experience, and a genuine subspecialist should answer without hesitation.

Search MSK is a UK directory of musculoskeletal specialists, searchable by region and declared subspecialty — filtering for knee cartilage or sports knee surgery returns surgeons for whom this is a stated focus area, rather than an occasional referral.