As an orthopaedic specialist, one of the most common dilemmas I see in clinic is patients with cartilage injuries receiving very different recommendations, from microfracture to more advanced cartilage restoration procedures. Common cartilage repair options include microfracture, autologous matrix induced chondrogenesis (AMIC®), and osteochondral grafting techniques. In reality, cartilage repair is not about choosing the most advanced technique, but selecting the procedure best suited to the specific defect and the patient.
With this in mind, this article outlines how cartilage defects are approached in clinical practice, and how treatment decisions are shaped by patient and defect characteristics. This is particularly important in high demand patients, where the margin for error is small and outcomes need to be predictable.
A Clinical Approach to Cartilage Injuries
In contemporary cartilage surgery, there is no single “best” procedure — only the procedure most appropriate for the specific defect. The challenge lies not in knowing which techniques are available, but in understanding when to use them and how to apply them properly. This calls for experience, technical precision, and the ability to individualise treatment according to both patient and defect characteristics.
The Patient Profile
I am a firm believer in treating patients rather than MRI findings. In my practice, clinical decision making always begins with understanding the patient’s functional demands before reviewing imaging. These might include the exercises they enjoy, work related demands such as stair climbing, prolonged standing, or deep squatting, and in competitive athletes, the timing of training cycles, season periods, and off seasons. These factors are crucial in planning a bespoke treatment approach.
For example, a patient with high physical demands who needs to return to work early might require a cartilage procedure that supports an earlier return to sport or function. Techniques such as AMIC® with a strong solid state bi-layer scaffold such as Chondro-Gide1,2, osteochondral autograft transfer system (OATS), or osteochondral allograft implantation (OCA) might therefore be considered. Conversely, an elderly patient with lower physical demands might be better suited to treatments such as microfracture and a soft gel-based scaffold, as a bridge to future joint replacement.
Nevertheless, regardless of patient profile, the main guiding principles for surgical intervention remain a cartilage defect that is:
- Focal - i.e. a clearly defined full thickness defect.
- Symptomatic - causing pain when the defect is loaded and tested.
- Contained -surrounded by normal healthy cartilage.
The Cartilage Defect & Joint Stability
After understanding the patient profile, we next review the MRI and assess the affected joint clinically. This is where surgical decision making becomes more nuanced.
For the cartilage defect, there are multiple factors that we assess:
Size, depth, and surrounding cartilage
- In relation to the patient’s size, is the defect considered small or large?
- Is there full thickness or partial thickness cartilage loss?
- Are the cartilage edges healthy or frayed?
These factors crucially affect the choice of surgery. As I discussed in my previous article “What is cartilage and why does it not heal by itself easily?”, cartilage is a structure that heals poorly, and cartilage repair depends heavily on the surrounding cartilage to support healing. A large defect will often require greater support from implants such as scaffolds, while poor surrounding cartilage can reduce healing potential. In my practice, I would usually resect poor quality surrounding cartilage until healthy, firm edges are present, even though this can increase the final size of the defect.
Bone involvement
- Is the bone beneath the cartilage affected?
- Are subchondral bone cysts present?
These factors influence the choice of surgery in terms of bone preparation. Cartilage repair cannot grow on poor subchondral bone. Options such as bone grafting, synthetic osteochondral scaffolds, or osteochondral grafting techniques such as OATS/OCA must therefore be considered.
Location
- Is the defect in a weightbearing region of the joint?
- Is it at the edge of the cartilage surface?
These factors are important in terms of post-operative rehabilitation and the choice of surgical procedure, particularly in ensuring that the repair can withstand strong weightbearing forces, or in accounting for the reduced surrounding cartilage available for healing when the defect lies close to the edge.
For the joint itself, we assess three main factors:
- Supporting structures and integrity, such as the meniscus in the knee.
- Stability, such as ligament tears within the joint.
- Mechanical loading, such as valgus or varus deformity of the joint axis.
These factors are important, in fact among the most important, before performing any cartilage surgery. For cartilage repair to have the best chance of succeeding, the affected joint must be stable and loading must be balanced. Otherwise, any cartilage surgery will be at a disadvantage from the very beginning, leading to poorer outcomes. In many ways, this is like a child trying to grow in an unstable home environment. Our aim, therefore, is to provide the best possible environment for cartilage repair and restoration.
Putting Them All Together and Creating a Bespoke Plan
Once we have these details, the next step is to choose the type of surgery. At this stage, the focus is not simply on the implant itself, but on selecting the approach that can create the most suitable biological and mechanical environment for healing.
For this reason, cartilage repair procedures should be approached in a bespoke way, with treatment tailored to each patient. The following sections outline the key treatment strategies and the clinical considerations behind each of them.
Marrow Stimulation Techniques as a Standalone Procedure
Generally, these are outdated and might carry more risks than benefits, as outlined in my previous article, “Microfractures for Cartilage Repair?”. Cartilage surgeons like myself have largely abandoned this as a standalone procedure.
Scaffolds
I broadly categorise scaffolds into three types:
1. Gel-based scaffolds: such as Cartfill, Chondrofiller, and minced cartilage constructs as a standalone option
These may be used for very small defects. However, the physical strength of these scaffolds is weak when handling high pressures and shears. This is because the subchondral bone under the cartilage is the structure that feels pain, and what it needs is a strong shield for protection. Gel-based scaffolds do provide a shield, but likely a soft one in the initial stages. This means that rehabilitation normally takes much longer, and would not be suitable for patients seeking a fast recovery or an early return to work or sport.
2. Malleable solid scaffolds: for example, Hyalofast
These are versatile scaffolds that can be moulded into almost any shape and provide better physical strength than gel-based scaffolds. I personally use them for small but deep cartilage defects, as they can be layered to fill the cartilage void. They are technically more challenging to apply than gel-based scaffolds, but their versatility across a wide range of cartilage defects is testament to their popularity. They are, however, limited to defects that are small to moderate in size, and their physical strength is still not sufficient for patients aiming for a fast return to sport, with high impact activity usually delayed for eight to 10 months.
3. Firm solid scaffolds: for example, Chondro Gide or AMIC®
These are among the strongest scaffolds in this class in terms of physical strength. They are ideal for moderate to large defects, as well as weightbearing surfaces, and are therefore better suited to active individuals aiming for an earlier return to sport. However, they are also technically challenging, arguably the most challenging, as the scaffold has to be templated to match the exact cartilage defect, and implantation therefore requires a high level of technical ability.
As a Geistlich AMIC® Chondro-Gide® Competence Center accredited practice, and as an ICRS international faculty member teaching these techniques at their masterclasses, I routinely perform and refine these procedures in clinical practice. The technique has further evolved into AMIC+, where biological augmentation such as bone marrow aspirate concentrate (BMAC) and or minced cartilage is used to improve the healing rates of these scaffolds2,3.
Marrow Stimulation Techniques as a Standalone Procedure
Generally, these are outdated and might carry more risks than benefits, as outlined in my previous article, “Microfractures for Cartilage Repair?”. Cartilage surgeons like myself have largely abandoned this as a standalone procedure.
Scaffolds
I broadly categorise scaffolds into three types:
- 1. Gel-based scaffolds: such as Cartfill, Chondrofiller, and minced cartilage constructs as a standalone option.
These may be used for very small defects. However, the physical strength of these scaffolds is weak when handling high pressures and shears. This is because the subchondral bone under the cartilage is the structure that feels pain, and what it needs is a strong shield for protection. Gel-based scaffolds do provide a shield, but likely a soft one in the initial stages. This means that rehabilitation normally takes much longer, and would not be suitable for patients seeking a fast recovery or an early return to work or sport.
- 2. Malleable solid scaffolds: for example, Hyalofast
These are versatile scaffolds that can be moulded into almost any shape and provide better physical strength than gel-based scaffolds. I personally use them for small but deep cartilage defects, as they can be layered to fill the cartilage void. They are technically more challenging to apply than gel-based scaffolds, but their versatility across a wide range of cartilage defects is testament to their popularity. They are, however, limited to defects that are small to moderate in size, and their physical strength is still not sufficient for patients aiming for a fast return to sport, with high impact activity usually delayed for eight to 10 months.
- 3. Firm solid scaffolds: for example, Chondro Gide or AMIC®
These are among the strongest scaffolds in this class in terms of physical strength. They are ideal for moderate to large defects, as well as weightbearing surfaces, and are therefore better suited to active individuals aiming for an earlier return to sport. However, they are also technically challenging, arguably the most challenging, as the scaffold has to be templated to match the exact cartilage defect, and implantation therefore requires a high level of technical ability.
As a Geistlich AMIC® Chondro-Gide® Competence Center accredited practice, and as an ICRS international faculty member teaching these techniques at their masterclasses, I routinely perform and refine these procedures in clinical practice. The technique has further evolved into AMIC+, where biological augmentation such as bone marrow aspirate concentrate (BMAC) and or minced cartilage is used to improve the healing rates of these scaffolds2,3.
Osteochondral Plugs
Osteochondral plugs are cylindrical units of cartilage and bone, used to plug into the defect when both cartilage and bone are involved. We can either use your own from another part of your joint in the form of an autologous graft such as OATS, tissue from a donor in the form of OCA, or synthetic manufactured options such as CartiHeal or MaioRegen.
One downside is that, in certain areas such as the patella, these cannot be performed arthroscopically and will require open surgery, leading to increased wound issues and longer healing time. Another weakness is that, for very large lesions without bone involvement, this would be significantly invasive, requiring multiple plugs and therefore not being feasible in the autologous setting.
However, they offer excellent physical strength, stronger than the scaffold class, and patients requiring a rapid return to function can start high impact exercise as early as three months after surgery because of their rapid integration. In short, this involves a bigger surgery with bigger sacrifices, but also stronger outcomes.
Osteochondral Plugs
Osteochondral plugs are cylindrical units of cartilage and bone, used to plug into the defect when both cartilage and bone are involved. We can either use your own from another part of your joint in the form of an autologous graft such as OATS, tissue from a donor in the form of OCA, or synthetic manufactured options such as CartiHeal or MaioRegen.
One downside is that, in certain areas such as the patella, these cannot be performed arthroscopically and will require open surgery, leading to increased wound issues and longer healing time. Another weakness is that, for very large lesions without bone involvement, this would be significantly invasive, requiring multiple plugs and therefore not being feasible in the autologous setting.
However, they offer excellent physical strength, stronger than the scaffold class, and patients requiring a rapid return to function can start high impact exercise as early as three months after surgery because of their rapid integration. In short, this involves a bigger surgery with bigger sacrifices, but also stronger outcomes.
What Determines Outcomes in Cartilage Repair
In the subspecialty of cartilage repair and regeneration, results depend not only on the procedure chosen, but also on how well it is performed and how suitably it is matched to the patient and the broader clinical setting. This is what makes cartilage repair such a technically demanding field, as knowing which options are available is only part of the task. Equally important is the judgement to determine when each approach is most suitable, and the circumstances in which it is most likely to perform well.
In my own practice, performing a high volume of cartilage repair procedures each year, together with a particular focus on single stage techniques and biologic augmentation strategies, has continually reinforced that good outcomes depend not simply on selecting a procedure, but on selecting the right one and applying it well. This becomes even more important in complex or high demand patients, where the margin for error is smaller and the consequences of a poorly matched or less precisely executed approach are greater. Ultimately, the success of cartilage repair lies not in the procedure alone, but in the judgement and technical expertise behind how it is chosen and carried out.
Speak to Oxford Cartilage & Sports Centre
Because treatment decisions in cartilage repair depend on multiple factors working together, from the characteristics of the defect and the condition of the underlying bone to joint stability, loading, and patient demands, this is not a field that can be approached in a one size fits all way. A bespoke approach is therefore essential, which is why specialist assessment matters, especially in a technically demanding area where judgement and experience play a central role in selecting the most appropriate strategy. In a focused consultation, Dr Francis Wong can assess how these factors come together within the wider clinical picture and translate them into a treatment plan that is best suited to the patient, the defect, and the demands of recovery. To speak with Oxford Cartilage & Sports Centre, please contact the clinic to book an appointment.
References:
- Ow ZGW, Ting KJE, Wong KL. Single-Stage Arthroscopic Cartilage Repair with Chondrectomy and Implantation of a Templated Membrane Collagen Scaffold with Bone Marrow Aspirate Concentrate Augmentation (AMIC Plus). Arthrosc Tech. 2023 Oct 30;12(11): e2085-e2091. doi: 10.1016/j.eats.2023.07.030. PMID: 38094947; PMCID: PMC10714417.
- Ow ZGW, Cheang HLX, Koh JH, Koh JZE, Lim KK, Wang D, Minas T, Carey JL, Lin HA, Wong KL. Does the Choice of Acellular Scaffold and Augmentation with Bone Marrow Aspirate Concentrate Affect Short-term Outcomes in Cartilage Repair? A Systematic Review and Meta-analysis. Am J Sports Med. 2023 May;51(6):1622-1633. doi: 10.1177/03635465211069565. Epub 2022 Feb 28. PMID: 35225004.
- Zhang EJX, Ow ZGW, Lie EV, Dhanaraj ID, Wong KL. Arthroscopic Cartilage Repair of the Patella with Minced Cartilage and Collagen Membrane Scaffold with Bone Marrow Aspirate Concentrate. Arthrosc Tech. 2024 Nov 13;14(4):103308. doi: 10.1016/j.eats.2024.103308. PMID: 40453020; PMCID: PMC12126052.
