Knee Cartilage
Demo Author One
Cartilage repair options for lasting joint health
A practical overview of cartilage repair, injection therapy, rehabilitation planning, and the clinical evidence that guides joint preservation care.
Who STACi is for
Am I a candidate for STACi? Who STACi is for
Who single-stage cartilage regeneration suits, who it needs discussing with, and how suitability is decided.
Reviewed byProf Paul Lee MBBch, FRCS (Tr & Orth), PhDLast reviewed 1 May 2026Quick answer
You may be a candidate for STACi if you have significant focal cartilage damage — often larger than about 2–4 cm² — with healthy tissue around it, you have been told a joint replacement is likely but are too young or active for one, and you want to keep your own joint. An imaging review confirms suitability.
The patient STACi was built for
STACi exists for one kind of patient above all: the person who has been told a joint replacement is coming, but who is too young or too active to accept one yet. If your cartilage is worn or torn in a defined area — rather than crumbling across the whole joint — regenerating that surface with your own cells can let you keep your natural joint instead of replacing it with metal and plastic.
The other group STACi was designed for is people turned away from the older cartilage cell therapies. ACi and MACi are largely capped at defects up to around 4 cm² and confined mainly to the knee. Being told a defect was “too big” for those techniques does not mean regeneration is off the table — it is precisely the situation the three-dimensional STACi scaffold was built to take on.
You are likely to be a good candidate if
- You have significant cartilage damage — often larger than about 2–4 cm² — with healthy tissue around it.
- You have been told a joint replacement is likely, but you are too young or too active to want one yet.
- You want to preserve your own joint rather than replace it.
- Your damage is focal (a defined area), or your surgeon judges the surrounding joint can support regeneration.
- You are willing to commit to a staged rehabilitation programme over 9–12 months.
STACi needs a closer conversation, and may not be the answer, if
- You have widespread, end-stage “bone-on-bone” arthritis across the whole joint — though other LCC options may still help, which is what the consultation is for.
- You have significant untreated joint instability or malalignment that would need correcting first (sometimes done alongside STACi).
- You are unable or unwilling to protect the joint during the early healing months.
- You have certain inflammatory joint diseases — assessed case by case.
Being turned down for the older ACi or MACi because a defect was “too big” does not mean STACi is out of reach — it is exactly what STACi was designed for. The only way to know is an imaging review.
How suitability is actually decided
No web page can tell you for certain whether STACi is right for you — that decision rests on your imaging. At consultation, Professor Lee reviews your scans to judge the size, depth and location of the damage, the health of the surrounding cartilage, and whether the joint is stable and well aligned enough to support regeneration. Where alignment or instability needs correcting, that can sometimes be done in the same operation.
If you would like a quick, no-obligation sense of whether it is worth an imaging review, our short self-assessment walks you through the same questions the team starts with — then routes you to a free discovery call. Take the STACi self-assessment.
Frequently Asked Questions
Am I too old or too young for STACi?
STACi is judged on the joint, not a birthday. It is most often chosen by people who are too young or too active to accept a joint replacement yet, but the deciding factors are the size and location of the cartilage damage and the health of the surrounding joint — which is what the imaging review assesses.
Is my defect too big for STACi?
Can STACi help if I already have some arthritis?
Focal cartilage damage with healthy surrounding tissue is ideal. Widespread, end-stage “bone-on-bone” arthritis across the whole joint is less suitable, though other LCC options may still help — that is what the consultation is for.
What if my knee is unstable or misaligned?
Significant instability or malalignment usually needs correcting for a cartilage repair to last. That can sometimes be done alongside STACi in the same operation. Professor Lee assesses this from your imaging.
Do I have to commit to a long recovery?
Yes. STACi asks for a staged rehabilitation over 9–12 months, because loading regenerating tissue too soon is the enemy of new cartilage. A willingness to protect the joint through the early months is part of being a good candidate. See the STACi recovery timeline.
How do I find out if I’m suitable?
Start with the free self-assessment or a discovery call, then book a consultation so Professor Lee can review your scans. Suitability is confirmed on imaging, not on symptoms alone.
Still have more specific concerns?
Free Discovery CallFind out if STACi is right for you
A free discovery call is the easiest first step; a consultation gets your imaging reviewed by the surgeon who would perform the procedure.
London Cartilage Clinic
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