Cartilage restoration is surgery to resurface a defined area of damaged cartilage in a joint, using either the patient's own cultured cartilage cells, a transplanted donor graft, or a scaffold implant. It is done to preserve the patient's own joint, and it is a different problem from widespread arthritis.
At Texas Orthobiologics in Dallas, Don Buford, M.D., a board-certified orthopedic surgeon, performs three of these procedures: MACI, osteochondral allograft transplantation, and the CartiHeal Agili-C implant.
This page covers what each one is, how the choice between them is made, and how cartilage surgery relates to the orthobiologic injections offered on the rest of this site. If your imaging has shown a cartilage defect, or you have been told you have a "hole" or a "crater" in the cartilage of your knee, this is the page you are looking for.
Why cartilage damage is its own problem
Articular cartilage is the smooth white surface covering the ends of the bones inside a joint. It lets the joint glide, and it spreads load across the bone underneath. It is also one of the few tissues in the body with essentially no blood supply of its own, which is the root of the difficulty: a full-thickness cartilage defect does not fill itself back in.
Left alone, a defect tends to behave in a predictable way. The exposed bone underneath becomes a source of pain. The rim of the defect is subject to shear every time the joint loads. What began as a discrete injury in an otherwise healthy joint can, over time, become a more diffuse problem across the whole surface.
That is the reasoning behind restoring the surface while the rest of the joint is still sound — not to reverse arthritis, but to treat a defect before it becomes arthritis.
Who cartilage restoration is for — and who it is not for
This is the single most important distinction on the page, and it is the one most often blurred elsewhere.
The presentation these procedures are designed for
- A discrete, well-defined cartilage or osteochondral defect — a specific area of damage with a definable border, visible on MRI or at arthroscopy
- A joint that is otherwise structurally sound: the rest of the cartilage surface is reasonable, the ligaments are competent, the meniscus is largely present, and the alignment does not load the defect abnormally
- Symptoms that match the lesion — pain localised to the area, sometimes catching, swelling after activity
- Often, though not always, a younger and active patient with a traumatic injury or osteochondritis dissecans rather than gradual wear
The presentation these procedures are not designed for
Widespread osteoarthritis is a different problem and needs a different conversation. When cartilage loss is diffuse rather than focal — when the whole surface is thin, when there is bone-on-bone contact across a compartment — resurfacing one patch does not address what is generating the symptoms, and these procedures are not indicated. Saying so is more useful than offering an operation that will not deliver.
For a joint in that condition, the options worth discussing are different, and orthobiologic injection is sometimes one of them. Which brings up a point worth being explicit about.
The three procedures
All three are performed for a discrete cartilage defect. They differ in what is used to resurface it, whether bone underneath is also being replaced, and whether the operation happens once or twice.
MACI — matrix-associated autologous chondrocyte implantation
A two-stage, cell-based repair using the patient's own cartilage cells.
At the first operation a small cartilage biopsy is taken from the knee. Those chondrocytes are grown in culture over a number of weeks and seeded onto a resorbable Type I/III collagen membrane. At a second operation, that membrane — now carrying the patient's own cells — is cut to the shape of the prepared defect and implanted onto it.
MACI was FDA-approved on 14 December 2016, for the repair of symptomatic single or multiple full-thickness cartilage defects of the knee, with or without bone involvement, in adults. It was the first FDA-approved cellularized scaffold product of its kind — a tissue-engineering approach that grows a patient's own cells on a scaffold before implanting them.
The trade-off is in the name: it is autologous, so there is no donor tissue involved at all, but it requires two operations separated by the time it takes to culture the cells.
Osteochondral allograft transplantation
A single-stage operation using a matched donor graft of living cartilage still attached to its own underlying bone.
The damaged area is removed as a cylinder or a shaped block, and a size-matched donor graft is placed into it. What distinguishes this from the other two is that it restores mature, already-organised cartilage immediately, rather than asking the body to build new tissue over time — and because the graft brings its own bone, it can replace bone that has been lost underneath the defect.
That makes it the usual answer for larger defects, for lesions where the bone beneath is involved, and for osteochondritis dissecans where a fragment has separated.
Its regulatory position is worth stating precisely, because it differs from the other two. An osteochondral allograft is human tissue for transplantation, regulated by the FDA under 21 CFR Part 1271 — an established framework of donor screening and testing, good tissue practice, and establishment registration requirements that tissue banks must meet. It is a well-defined pathway with decades of published human outcomes and graft survivorship data behind it.
CartiHeal Agili-C
A cell-free scaffold implant placed in a single operation.
No cells are cultured and no donor cartilage is used. The implant is placed into the prepared defect in one procedure.
Agili-C received FDA Premarket Approval (PMA) on 30 March 2022 — the most demanding regulatory pathway that exists for a device — for the treatment of ICRS grade III or above knee joint surface lesions, with a total treatable area of 1 to 7 cm², without severe osteoarthritis.
The approval was supported by a multicentre randomised controlled trial of 251 patients, randomised two-to-one against microfracture and debridement — the previous surgical standard of care. At 24 months:
- Mean KOOS improved from 41.2 to 84.3 in the Agili-C group
- Mean KOOS improved from 41.7 to 62.0 in the control group
- Responder rate: 77.8 per cent against 33.6 per cent
That paragraph is worth reading twice, because of what it is: a named comparator, a randomised design, a stated patient number and reported outcome scores. That is the evidence standard this practice applies, and it is the reason these procedures are offered while several better-marketed alternatives are not.
How the choice between them is made
There is no default. The decision is made on the specific lesion, and the factors that move it are concrete:
- Size of the defect. The approved indication for Agili-C is stated in square centimetres for a reason — area matters, and larger lesions push the decision in a different direction from small ones.
- Whether the bone underneath is involved. A defect that is purely cartilage is a different reconstruction from one where bone has been lost or a fragment has separated. Only one of these three brings its own bone.
- Location on the joint surface — and how much load that particular area sees.
- The condition of the rest of the joint: the opposing surface, the meniscus, the ligaments, and the alignment of the limb. A defect that keeps recurring because of how the joint is loaded needs that addressed too.
- One operation or two. MACI requires a staged approach. The other two do not. For some patients that is decisive and for others it is not.
- Age, activity and what the patient needs the joint to do.
Most of this is settled by reading an MRI carefully against the examination, and sometimes by looking at the surface arthroscopically before committing to a plan.
How this relates to the injections on the rest of this site
Most of Texas Orthobiologics is about platelet-rich plasma and bone marrow aspirate concentrate — office injections, prepared from the patient's own tissue, placed under ultrasound guidance. Cartilage restoration is none of those things. It is an operation.
They are not competing options, and it is worth being direct about the difference. No injection has been shown to regrow a joint surface — not PRP, not bone marrow concentrate, and not any product currently marketed as a stem cell treatment. What the better injection studies support is meaningful reduction in pain and improvement in function in appropriately selected patients. That is a real and useful thing, and it is not the same thing as filling a full-thickness defect.
So the two answer different questions:
- A discrete full-thickness defect in a sound joint is a structural problem. Cartilage restoration addresses it structurally.
- A painful joint with diffuse wear is a different problem, and an orthobiologic injection is one of the reasonable things to discuss for it.
Being able to offer both is the point. The recommendation is not shaped by what happens to be available, and a patient who does not need an operation will be told so.
Why these three, and not others
The same standard is applied here as everywhere else on this site:
No product is used unless it has a clear FDA regulatory pathway for use in humans and clear human clinical outcomes data showing that it is safe and that it works for the indication being treated. Both halves, not either one.
The three procedures on this page reach that bar by three different routes, and the distinctions are real rather than cosmetic:
- MACI — FDA-approved, for a specific written indication.
- CartiHeal Agili-C — FDA Premarket Approval, supported by a randomised controlled trial against the previous standard of care.
- Osteochondral allograft — human tissue for transplantation under 21 CFR Part 1271, with decades of published outcomes behind it.
Note that one of the three uses donor tissue, and it is still offered. The standard is not "autologous only." It is evidence and regulatory pathway, applied the same way to everything. What it excludes — amniotic fluid, Wharton's jelly and exosome products, all of which are considered unapproved drugs by the FDA and none of which are approved for any treatment indication — is excluded by the same rule that admits these three. The full reasoning is set out here.
Recovery and rehabilitation timelines
Recovery from cartilage restoration is longer and more structured than recovery from an injection, and it is genuinely the part that determines the result. New cartilage, or a transplanted graft, has to integrate with the bone and tissue around it before it can take full load.
The chart below sets out the general shape of that commitment.
General rehabilitation milestones by procedure
This chart is general information, not specific medical advice. Rehabilitation protocols are established individually by the treating surgeon for each patient, based on what is found at the time of surgery and on how the knee responds afterwards. Nothing here is a schedule any individual patient will be held to, and nothing here should be used to plan your own recovery. Your protocol will be given to you directly.
| Procedure | Protected / partial weight bearing | Running | Unrestricted sport |
|---|---|---|---|
| MACI — tibiofemoral lesion | Gradual loading for approximately 7–9 weeks | Usually 7–9 months for a single lesion; 10–12 months for multiple or complex lesions | Cutting and contact sport typically 10–12+ months |
| MACI — patellofemoral lesion | Often immediate weight bearing with the brace locked in extension; progression varies with lesion number and concomitant surgery | Approximately 7–9 months for a single lesion; 10–12 months for multiple lesions | Usually 10–12+ months |
| Osteochondral allograft | Commonly non-weight-bearing or toe-touch for 2 weeks, then partial weight bearing until approximately 6–10 weeks | Commonly begins around 5–6+ months, after graft healing is confirmed | Typically 8–12 months; studies in athletes suggest closer to 9–12 months |
| CartiHeal Agili-Cisolated weight-bearing condylar lesion | Toe-touch weight bearing for 4 weeks; progressive partial weight bearing during weeks 5–6; full weight bearing around weeks 6–8 if the knee remains quiet | No earlier than approximately 9 months | Pivoting and contact sport at 12+ months |
The Agili-C figures are a practical default for an isolated weight-bearing condylar lesion specifically, and full weight bearing is advanced only if the knee stays quiet. A lesion elsewhere in the joint, or one treated alongside other work, is prescribed differently.
Worth understanding why any of these numbers vary at all. An FDA approval establishes the indication — which lesions a product may be used for. It does not set the rehabilitation. That prescription is left to the treating surgeon and individualised to the patient. So a protocol is a clinical judgement made about your knee, not a specification printed on a box.
What the chart is telling you
Four things worth drawing out, because they are the parts patients most often have not been told.
Weight bearing and return to sport are separate questions. Coming off crutches is not the same as being cleared to run, and running is not the same as being cleared for cutting and contact. Those three milestones are months apart, and the middle one is where people tend to get impatient.
Where the lesion sits changes the early phase more than the late one. A patellofemoral MACI often allows immediate weight bearing with the brace locked in extension, while a tibiofemoral lesion is loaded gradually. By the time you get to running and sport, the two converge.
More than one lesion moves the timeline. A single MACI lesion is usually looking at seven to nine months before running; multiple or complex lesions run to ten to twelve. If something else was addressed at the same operation — alignment, meniscus, ligament — that shifts it again.
Some milestones are conditional, not scheduled. Full weight bearing after Agili-C is advanced if the knee remains quiet, and running after an osteochondral allograft begins after graft healing is confirmed. Those are gates, not dates. A knee that is still irritable does not progress just because the calendar says it should.
The protocol is set out before surgery rather than afterwards, so the commitment involved is clear while the decision is still being made. It is the right thing to ask about at the consultation, and it is a fair reason to decide the timing is not right for you yet.
Who performs the surgery
These procedures are performed by Don Buford, M.D., a board-certified orthopedic surgeon.
The combination on offer here is unusual, and it is worth understanding why it matters. Most practices marketing cartilage and joint treatment in this market fall into one of two groups. Injection clinics cannot perform cartilage restoration at all, so an injection is the only thing they can recommend. Surgical practices frequently do not offer well-prepared orthobiologics, so the biologic conversation does not really happen.
When both are genuinely available, the question at the consultation can be the right one — what does this joint actually need — rather than a question shaped by what the practice is equipped to deliver.
Request an appointment or call (877) 777-8883.
Common questions
What is cartilage restoration surgery?
Cartilage restoration is surgery to resurface a defined area of damaged articular cartilage in a joint, using the patient's own cultured cartilage cells, a transplanted donor graft, or a scaffold implant. It is done to preserve the patient's own joint, and it is used for a discrete defect rather than for widespread arthritis.
Which cartilage restoration procedures do you perform?
Three: MACI (matrix-associated autologous chondrocyte implantation), osteochondral allograft transplantation, and the CartiHeal Agili-C implant. All three are performed by Don Buford, M.D., a board-certified orthopedic surgeon.
What is MACI?
MACI is matrix-associated autologous chondrocyte implantation - a two-stage cartilage repair using the patient's own cartilage cells. A small biopsy is taken at a first operation, the chondrocytes are grown in culture and seeded onto a resorbable Type I/III collagen membrane, and that membrane is implanted onto the prepared defect at a second operation. MACI was FDA-approved on 14 December 2016 for the repair of symptomatic single or multiple full-thickness cartilage defects of the knee, with or without bone involvement, in adults. It was the first FDA-approved cellularized scaffold product of its kind.
What is an osteochondral allograft?
An osteochondral allograft is a matched donor graft of living cartilage still attached to its own underlying bone, transplanted in a single operation to resurface a defect. Because it brings its own bone, it can replace bone lost beneath the lesion, and because the cartilage is already mature and organised it does not have to be grown. It is usually the answer for larger defects, for lesions with bone involvement, and for osteochondritis dissecans. It is human tissue for transplantation regulated by the FDA under 21 CFR Part 1271.
What is the CartiHeal Agili-C implant?
Agili-C is a cell-free scaffold implant placed in a single operation to resurface a cartilage or osteochondral defect - no cells are cultured and no donor cartilage is used. It received FDA Premarket Approval on 30 March 2022 for ICRS grade III or above knee joint surface lesions with a total treatable area of 1 to 7 square centimetres, in the absence of severe osteoarthritis. The approval was supported by a multicentre randomised controlled trial of 251 patients against microfracture and debridement, in which mean KOOS scores at 24 months improved from 41.2 to 84.3 with Agili-C compared with 41.7 to 62.0 in the control group, with a responder rate of 77.8 per cent against 33.6 per cent.
Am I a candidate for cartilage restoration?
The presentation these procedures are designed for is a discrete, well-defined cartilage or osteochondral defect in a joint that is otherwise structurally sound - reasonable cartilage elsewhere, competent ligaments, a largely intact meniscus, and alignment that does not abnormally load the defect. Widespread osteoarthritis is a different problem and these procedures are not indicated for it. Candidacy is decided on MRI read against the examination, and sometimes on arthroscopic assessment of the surface.
Can cartilage restoration be done if I already have arthritis?
It depends on how much and where. These procedures are for focal defects in a joint that is otherwise sound, and the approved indication for the Agili-C implant specifically excludes severe osteoarthritis. When cartilage loss is diffuse rather than focal, resurfacing one area does not address what is generating the symptoms. That is a different conversation, and an orthobiologic injection is sometimes one of the reasonable things to discuss for it.
How is it decided which procedure I need?
On the specific lesion. The factors that move the decision are the size of the defect, whether the bone underneath is involved or has been lost, where on the joint surface it sits and how much load that area sees, the condition of the rest of the joint including meniscus, ligaments and alignment, and whether a staged two-operation approach is workable for that patient. There is no default choice.
Is cartilage restoration the same as a stem cell injection?
No, and the difference matters. Cartilage restoration is an operation that structurally resurfaces a defect. No injection - not PRP, not bone marrow concentrate, and not any product marketed as a stem cell treatment - has been shown to regrow a joint surface. Injections and cartilage surgery answer different questions, and both are available here.
What is recovery like after cartilage restoration?
Longer and more structured than recovery from an injection, and it is the part that largely determines the result. In general terms: protected or partial weight bearing is measured in weeks, running in months, and unrestricted cutting or contact sport at around 10 to 12 months or more. Every protocol is personalised to what is actually found - the size and location of the lesion, whether bone was involved, whether anything else was addressed at the same operation, and how the joint responds. The protocol is set out before surgery rather than afterwards, so the commitment is clear while the decision is still being made.
How long is recovery after MACI?
For a tibiofemoral lesion, gradual loading for approximately 7 to 9 weeks; running usually at 7 to 9 months for a single lesion and 10 to 12 months for multiple or complex lesions; cutting and contact sport typically at 10 to 12 months or more. For a patellofemoral lesion, weight bearing is often immediate with the brace locked in extension, with progression varying by lesion number and any concomitant surgery; running at approximately 7 to 9 months for a single lesion and 10 to 12 months for multiple lesions; unrestricted sport usually at 10 to 12 months or more. These are general figures - the protocol is personalised to the findings.
How long is recovery after an osteochondral allograft?
Commonly non-weight-bearing or toe-touch for 2 weeks, then partial weight bearing until approximately 6 to 10 weeks. Running commonly begins around 5 to 6 months or more, after graft healing is confirmed. Unrestricted sport is typically 8 to 12 months, and studies in athletes suggest closer to 9 to 12 months. These are general figures - the protocol is personalised to the findings.
How long is recovery after the CartiHeal Agili-C implant?
For an isolated weight-bearing condylar lesion, Dr. Buford's practical default is toe-touch weight bearing for 4 weeks, progressive partial weight bearing during weeks 5 to 6, and full weight bearing around weeks 6 to 8 if the knee remains quiet. Running no earlier than approximately 9 months, and unrestricted pivoting or contact sport at 12 months or more. A lesion elsewhere in the joint, or one treated alongside other work, is prescribed differently. The FDA approval establishes which lesions the implant may be used for; it does not set the rehabilitation, which is left to the treating surgeon and individualised to the patient.
When can I run again after cartilage surgery?
Running is a separate milestone from coming off crutches, and the two are months apart. After MACI, running is usually at approximately 7 to 9 months for a single lesion and 10 to 12 months for multiple or complex lesions. After an osteochondral allograft it commonly begins around 5 to 6 months or more, once graft healing has been confirmed. After an Agili-C implant for an isolated weight-bearing condylar lesion, no earlier than approximately 9 months. Clearance for cutting and contact sport comes later again in every case.
Do you treat osteochondritis dissecans?
Yes. Osteochondritis dissecans, in which a fragment of cartilage and its underlying bone separates from the joint surface, is one of the classic indications for cartilage restoration - and because the bone beneath is involved, it often points toward osteochondral allograft transplantation.
