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Cartilage Regeneration Surgery

Persistent knee pain from a cartilage lesion? Discover the options, procedure and recovery for cartilage regeneration surgery.

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Overview

Cartilage is unable to heal itself, and so this is a very difficult area to treat. This is a fascinating and complex area of knee surgery. Thanks to advances in biological regenerative treatment and bio-materials, we now have the ability to treat cartilage defects effectively through a number of techniques:

  • AutoCart – single-stage cartilage repair
  • ACI – Autologous Chondrocyte Implantation
  • Osteochondral Allograft Transplant
  • Focal resurfacing

The starting point isn't which technique to use, but what kind of defect is being treated.

Where the damage is a surface chondral lesion — the cartilage itself is damaged but the underlying bone is intact — the defect can usually be repaired directly by resurfacing that area with new cartilage. This is where AutoCart, or occasionally ACI, comes in.

Where the damage is a larger osteochondral defect — the cartilage loss is deeper and involves the underlying (subchondral) bone — cartilage alone isn't enough to reconstruct the joint surface, and the bone itself needs replacing along with it. In an otherwise healthy knee, this is where an osteochondral allograft is usually the better option.

Lesion size, depth, and bone involvement are assessed on MRI and confirmed at arthroscopy, and used by Mr Barkatali to determine which of the techniques is right for a particular knee.

The Procedure

AutoCart – single-stage cartilage repair

For small surface lesions, Mr Barkatali’s go-to technique is AutoCart. It's a one-step, single-stage procedure: cartilage is harvested from the patient's own knee during the same operation, mechanically prepared into a graft, and implanted directly onto the damaged area — all in a single sitting, without the delay of sending cells away to be grown in a lab.

Published outcome data on this technique is encouraging. A five-year follow-up study of single-step autologous minced cartilage repair reported good patient-reported outcomes and a low rate of further surgery, with satisfactory function scores at final follow-up and only a small proportion of patients needing revision surgery. A separate comparative study of patients treated with AutoCart, MACI or AMIC found that all three techniques improved pain and function at two years, with AutoCart showing the greatest overall improvement from baseline.

ACI – Autologous Chondrocyte Implantation

ACI is a longer-established technique, sometimes still referred to as the traditional gold standard for cartilage regeneration, but it's a two-stage surgery, and at present it isn't widely available and can be expensive.

Step 1: Surgery is carried out to assess the lesion and harvest cartilage from the periphery of the knee. This allows the patient's own chondrocytes to be isolated. The cells are sent to a lab, where they are expanded and turned into a cartilage transplant graft. This step takes around 8-12 weeks.

Step 2: Once the cartilage graft is ready, a second operation is needed to implant it into the knee in the desired area, fix it into place and seal it.

Recovery after AutoCart and ACI

Cartilage repair is a slow biological process, and full recovery from AutoCart or ACI takes around 18 months. Progress is checked with MRI scans at 6 and 12 months after surgery.

For the first six weeks, the patient is kept partial or non-weight-bearing, using crutches and a brace to protect and offload the newly grafted area. Loading the knee with full body weight too soon risks disrupting the freshly repaired site and damaging the developing graft before it's had a chance to establish itself.

The graft then progresses through several recognised phases of cartilage maturation:

  • Proliferation (roughly the first 6 weeks) – the graft is at its most vulnerable, and protected weight-bearing is essential
  • Transition (around weeks 6-12) – the repair tissue firms up and begins to integrate with the surrounding bone and cartilage
  • Remodeling (around 3-8 months) – the tissue continues to reorganise into a more structured, durable form, allowing a gradual return to normal loading and activity
  • Maturation (up to around 18 months) – the graft reaches its final mechanical strength

The reason this takes so long is that chondrocytes, the cells that produce cartilage, are naturally slow-metabolising cells. It takes around 18 months for the newly formed, hyaline-like cartilage to become fully load-bearing and to match the mechanical properties of the surrounding native cartilage.

Osteochondral Allograft Transplant

For larger lesions in an otherwise healthy knee where the subchondral bone is also involved, an osteochondral allograft is generally the better option. This operation uses donor tissue from a matched knee joint. The patient is assessed with a CT and/or MRI scan, and the dimensions of the knee joint and the defect are measured. An exact-match donor is found and the tissue brought to theatre, where it's cleaned and any host cells removed to eliminate compatibility issues. The damaged area is prepared, the donor cartilage and bone cut to match using specialised equipment, and the allograft placed into the patient's knee.

The main advantage of this technique is that it transplants healthy, live hyaline cartilage with living chondrocytes already in place, and because it's donor tissue that's been fully screened and processed, there's no risk of disease transmission. The main drawback is practical: graft availability, and the time it can take to procure a matched graft.

Recovery after Osteochondral Allograft Transplant

Recovery after an osteochondral allograft is quicker than after AutoCart or ACI, because there's no cartilage graft that needs to mature over time — the allograft is already mature hyaline cartilage and bone.

The initial protection phase is similar to AutoCart and ACI: for the first six weeks, the knee is protected with bracing and restricted, partial weight-bearing to allow the transplanted tissue to settle in without being disrupted. After six weeks, the patient can progress to full weight-bearing. By around six months, the graft is usually fully incorporated and healed, and the patient can begin working with physiotherapy towards a full return to activity.

Focal resurfacing

This procedure is used where other attempts at cartilage regeneration have failed, or where the lesion is too large to treat with the other methods.

It's essentially a mini arthroplasty procedure, in which a small part of the diseased joint is replaced with an implant. Instead of cartilage, the damaged area is replaced with a polyethylene-coated implant fixed into the bone. This gives good coverage of the damaged area and allows the patient to weight-bear without pain.

As it's an arthroplasty procedure, it will eventually become loose over time and require revision. Short to medium-term results are good.

Outcomes

  • 20+ years of experience
  • 5,000 + surgeries
  • <1% complication rate

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“Finding Mr Barkatali was a turning point in Adam's recovery journey, having broken his kneecap at 16 and gone through several surgeries over the years at 18 we were told he would be left with a limp. Bilal didn't just offer the usual options, he went outside the box and under his care Adam had a pioneering surgery which gave him his full mobility back & the ability to walk , run and eventually kick a ball around! We will always be grateful that he was recommended to us & gave Adam his future back and treated him with such patience & kindness.”

The Bellamy Family on behalf of Adam, Osteochondral Allograft Transplant + AutoCart Surgery Jul 24, aged 19.

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Patient Interview

Frequently asked questions

Cartilage regeneration techniques work best in patients with a focal (localised) area of cartilage damage, rather than widespread osteoarthritis across the whole knee. They’re particularly well suited to younger, active patients, as the goal is to preserve the natural knee joint and delay or avoid the need for knee replacement. Factors such as your age, activity level, weight, and the size and location of the defect all influence which technique — if any — is appropriate for you. Mr Barkatali will assess this carefully using MRI and, where needed, arthroscopy.

Age isn’t a strict cut-off, but it is an important factor. Cartilage regeneration techniques like AutoCart and ACI are generally most successful in younger patients with good bone quality and no widespread arthritis, as the goal is long-term biological repair. Older patients, or those with more generalised wear in the joint, may be better suited to alternative options such as focal resurfacing or, in more advanced cases, partial or total knee replacement.

The surgery can be carried out under general anaesthesia (where you're fully asleep).

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As with any knee surgery, potential risks include:

  • Infection
  • Bleeding
  • Pain
  • Stiffness
  • Damage to nearby blood vessels or nerves
  • Graft failure or incomplete integration
  • Need for further or revision surgery in future

Mr Barkatali will discuss how these risks apply to your specific case and chosen technique.

Yes — for the first six weeks after AutoCart, ACI, or osteochondral allograft surgery, you’ll typically use a brace and crutches to protect the repair with partial or non-weight-bearing precautions. This protected period is essential to give the graft the best chance of healing successfully.

This depends on the technique used and the physical demands of your job. Given the extended protected weight-bearing period after AutoCart, ACI, or osteochondral allograft surgery, many patients need 6–12 weeks off work if their role is desk-based, with physically demanding jobs often requiring several months, in line with the graft’s maturation timeline. Mr Barkatali can advise based on your specific procedure and occupation.

As you’ll typically be partial or non-weight-bearing for the first six weeks, driving isn’t usually possible during this period. Once you’re able to bear weight comfortably, walk without crutches, and perform an emergency stop safely, you can normally resume driving — Mr Barkatali will confirm when this is appropriate based on your recovery and the technique used.

Yes — physiotherapy is an essential part of recovery from any cartilage procedure. Your physiotherapist will guide you through each stage of graft protection and rehabilitation, from early protected weight-bearing through to strengthening and, eventually, a return to normal activity. Close communication between you, your physiotherapist, and Mr Barkatali ensures the graft is loaded at the right pace throughout its maturation.

Recovery is monitored with regular clinical reviews and MRI scans — typically at 6 and 12 months after AutoCart or ACI — to check that the graft is healing and maturing as expected. This allows Mr Barkatali to confirm your progress and guide when it’s safe to advance your rehabilitation and activity levels.

During the early protection phase, high-impact activities, twisting or pivoting movements, and deep squatting should be avoided, as these can place excessive strain on the healing graft. Your physiotherapist and Mr Barkatali will guide you on when it’s safe to reintroduce these movements as your graft progresses through its maturation phases.

Some post-operative pain, swelling, and stiffness are normal, particularly in the first few weeks, and are managed with pain relief medication, ice, and elevation. Any discomfort is generally manageable and improves steadily as you progress through rehabilitation.

This depends on the technique used and how your individual repair progresses. Because AutoCart and ACI grafts take up to 18 months to fully mature, a return to high-impact or pivoting sports is generally more gradual and closely guided by MRI follow-up. Recovery after an osteochondral allograft tends to progress a little faster, with physiotherapy-guided return to activity often beginning around the six-month mark. Mr Barkatali and your physiotherapist will advise on safe timeframes based on your progress.

Mr Barkatali assesses the size, depth, and location of the cartilage defect using MRI, confirmed at arthroscopy. This — along with factors such as your age, activity level, and whether the underlying bone is involved — determines whether AutoCart, ACI, osteochondral allograft, or focal resurfacing is the most suitable option for you.

Outcomes vary by technique. AutoCart and ACI aim to regenerate durable, natural-like cartilage, with good medium- to long-term results reported in the literature. Osteochondral allografts transplant mature, living cartilage and bone, offering good durability in an otherwise healthy knee. Focal resurfacing, being an implant-based solution, will eventually wear over time and is likely to require revision in the future.

Many patients experience significant improvements in pain and function, particularly once the graft has matured. However, because cartilage regeneration is a slow biological process, it’s important to have realistic expectations about timescales — full benefit is often not felt until closer to the 12–18 month mark, especially with AutoCart or ACI.

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