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Who STACi is for

Am I a candidate for STACi? Who STACi is for

Who the surgical Structure, Seed, Soil and Signal cartilage pathway may suit—and how imaging separates it from NanoACi.

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Professor Paul LeeReviewed byProfessor Paul LeeCartilage and joint preservation expertise
Last reviewed 1 May 2026
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Quick answer

You may be a candidate for STACi if you have cartilage damage for which the joint also needs surgical preparation or mechanical correction before biology can be placed credibly. This may include defect preparation, alignment, stability or associated damage. Imaging—not the treatment name—confirms which structural work is required and whether joint preservation is realistic.

The patient STACi was built for

STACi is for cartilage damage that cannot be separated from the mechanics around it. A non-arthroscopic pathway may be sensible when the joint is structurally suitable; STACi becomes the clearer lane when surgery is needed to prepare the defect, restore useful stability, correct relevant loading or deal with associated pathology before the biological repair is placed.

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.
  • Your imaging shows that the joint needs surgical defect preparation, stabilisation, alignment correction or treatment of associated mechanical damage before biological repair is placed.
  • 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.
  • The structural problem cannot be corrected sufficiently to give a cartilage repair a credible mechanical environment.
  • 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.

Which joints

STACi can be used in any joint where cartilage is damaged. The knee is the most common, because focal cartilage damage happens there most often, but the same scaffold-based principle works across the body.

KneeHipShoulderAnkleElbowFootHandWrist

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.

STACi procedureSelf-assessmentRecovery timelineThe evidenceSTACi in LondonSTACi costAbout Professor Paul Lee
Knee MRI scan reviewed on a monitor to assess suitability
Suitability for cartilage cell therapy is judged on your imaging and your own cells.
consulting-in-office-with-pen

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?

Unlikely — larger defects are exactly what STACi’s 3D scaffold was designed for. Older ACi and MACi are largely capped around 4 cm²; STACi can take on larger, more complex damage. If you were turned down for those techniques on size, STACi is worth reviewing.

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?

Relevant instability or malalignment is one reason STACi may be chosen over NanoACi. The first S is Structure: where indicated, the mechanical problem is corrected within the surgical plan before Seed, Soil and Signal are applied. Not every STACi case needs an osteotomy or ligament procedure; imaging determines the structural work required.

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?

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Find 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.

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