London Cartilage Clinic IconLondon Cartilage Clinic66 Harley Street
Physiotherapist guiding a patient through knee rehabilitation

Recovery and rehabilitation

ACI Recovery Time: A Stage-by-Stage Rehabilitation Timeline

What ACI recovery looks like month by month — crutches, physiotherapy, activity and sport — and how single-stage STACi removes the wait between operations.

Free Discovery CallBook a Consultation
Prof Paul LeeReviewed byProf Paul LeeLast reviewed 1 May 2026

Quick answer

ACI recovery is gradual and staged. Most patients use crutches for protected weight-bearing for six to eight weeks, begin gentle range-of-motion with physiotherapy early, return to low-impact activity around four to six months, and higher-impact sport from nine to twelve months. ACI also needs a four-to-six-week wait between its two operations — which single-stage STACi removes.

Why cartilage recovery takes patience

New cartilage cannot be rushed. After ACI, the implanted cells need time to settle, mature and gradually take on the load of the joint. Push too hard too soon and the young repair tissue can be damaged before it is ready; protect it well and it matures into durable, functioning cartilage. That is why ACI rehabilitation is measured in months rather than weeks, and why the timeline is staged — each phase is designed to add load only when the repair can take it. The early pathway is broadly the same for ACI, MACi and STACi, because all three are growing your own cartilage cells into a defect.

The ACI recovery timeline, stage by stage

  1. Weeks 0–8 — protected weight-bearing

    Crutches are used to keep weight off the repair, easing back gradually under your surgeon’s guidance. The exact plan depends on where in the joint the defect sits.

  2. Early weeks — gentle range of motion

    Physiotherapy starts early with controlled movement to nourish the cartilage and keep the joint supple, without loading the repair. A continuous passive motion routine may be used for some patients.

  3. Months 2–4 — building strength

    Weight-bearing progresses to normal walking, and rehabilitation shifts towards rebuilding the muscle strength lost during the protected phase.

  4. Months 4–6 — low-impact activity

    Cycling, swimming and similar low-impact activity typically resume in this window as the repair matures.

  5. Months 9–12 — higher-impact sport

    Running, pivoting and contact sport are usually the last to return, once the new cartilage is robust enough to take impact.

Every timeline is individual — your surgeon and physiotherapist set your milestones based on your joint, your defect and your progress.

The part of ACI recovery people forget: the wait between operations

Recovery does not begin at the implantation operation. ACI is a two-stage procedure: first a keyhole operation to biopsy your cartilage cells, then a four-to-six-week wait while those cells are grown in a specialist laboratory, and only then the second operation to implant them. For many patients that gap — two anaesthetics, two recoveries and a period of uncertainty in between — is one of the harder parts of the whole pathway, even though it does not appear on a standard rehabilitation chart.

How single-stage STACi changes the picture

STACi keeps the same careful, staged rehabilitation — protected weight-bearing, early physiotherapy, a gradual return to activity and then sport — because it is still growing your own cartilage. What it changes is the front of the pathway. In most cases STACi is done in a single operation, with the laboratory step brought into theatre, so there is no four-to-six-week wait between two surgeries and no second anaesthetic. You begin one rehabilitation journey, once.

The rehabilitation after STACi looks much like ACI’s. The difference is that you get there after one operation, not two — which for many patients means a simpler, shorter overall pathway.

ACi explainedAm I a candidate for ACI?ACI on the NHSACI cost UKSTACi procedure
Cartilage cells prepared during a single-stage procedure
Single-stage STACi brings the laboratory step into theatre, removing ACi's wait between two operations.
consulting-in-office-with-pen

Frequently Asked Questions

How long does ACI take to recover from?

Recovery is staged over roughly a year. Protected weight-bearing on crutches usually lasts six to eight weeks, low-impact activity returns around four to six months, and higher-impact sport from nine to twelve months. The new cartilage needs time to mature, so the timeline is deliberately gradual.

When can I walk normally after ACI?

Crutches are typically used for six to eight weeks of protected weight-bearing, after which most patients progress to normal walking over the following weeks. Your surgeon sets the exact schedule based on where the defect is in the joint.

When can I return to sport after ACI?

Low-impact activity such as cycling and swimming usually resumes around four to six months, while higher-impact sport — running, pivoting, contact sport — generally returns from nine to twelve months, once the repair is robust enough to take impact.

Is STACi recovery faster than ACI?

The rehabilitation phase is similar, because both grow your own cartilage. The practical difference is that STACi is single-stage in most cases, removing ACI’s four-to-six-week wait between two operations and the second anaesthetic, which shortens and simplifies the overall pathway.

Why is cartilage recovery so slow?

New cartilage tissue is fragile as it matures and can be damaged if loaded too early. The staged timeline adds weight and impact only as the repair strengthens, which protects the result. Rushing risks the very tissue the surgery was done to create.

Will I need physiotherapy after ACI or STACi?

Yes. Structured physiotherapy is central to the result — early controlled movement to nourish the cartilage, then progressive strengthening. At London Cartilage Clinic, twelve months of follow-up is included in the STACi pathway.

Still have more specific concerns?

Free Discovery Call

Planning around a cartilage recovery?

A free fifteen-minute discovery call can talk you through what to expect. To map a timeline to your own joint, book a consultation with Professor Lee.

Free Discovery CallBook a Consultation

London Cartilage Clinic

Latest Insights

Clinical updates, cartilage treatment guidance, and recovery-focused articles from our specialist team.

View all insights
Privacy & Cookies Policy