Overview

A cartilage defect is a painful condition in which a small, isolated area of cartilage becomes damaged within an otherwise healthy knee. If left untreated, the damage can spread to the surrounding cartilage over time, eventually progressing to full-blown osteoarthritis.

Cartilage can be damaged as a result of trauma, or through other conditions such as Osteochondritis Dissecans (OCD). Both can lead to a painful lesion in the joint, which — if not properly treated — may progress to early joint degeneration and osteoarthritis.

These lesions are generally classified as either:

  • Chondral — affecting the cartilage only, or
  • Osteochondral — affecting the cartilage along with some of the underlying bone.

Unlike many other tissues in the body, cartilage has very limited ability to heal itself, which has traditionally made these injuries difficult to treat. However, thanks to advances in biological regenerative treatments and bio-material science, cartilage defects can now be treated successfully, helping to restore joint health and prevent further deterioration.

What causes cartilage injuries?

Cartilage damage can occur for a number of reasons, including:

  • Direct trauma — a sudden knock, twist, or impact to the knee, often during sport or an accident, can shear or crack the cartilage surface.
  • Osteochondritis Dissecans (OCD) — a condition, most often affecting younger or adolescent patients, in which a fragment of cartilage and underlying bone loses its blood supply and can become partially or fully detached.
  • Repetitive stress — ongoing overload of the joint, particularly in athletes, can gradually wear down the cartilage surface over time.
  • Underlying joint instability — conditions such as ligament injuries or misalignment of the knee can place uneven pressure on the cartilage, making it more vulnerable to damage.
  • Previous knee injury or surgery — damage to related structures, such as the meniscus or ligaments, can alter how load is distributed across the joint and increase the risk of cartilage injury.

Symptoms

The symptoms of a cartilage defect can vary depending on its size, location, and severity, but commonly include:

  • Pain, particularly during or after activity
  • Swelling in the knee
  • A sensation of catching, clicking, or locking within the joint
  • Reduced range of movement
  • A feeling of instability or the knee "giving way"

Because these symptoms can overlap with other knee conditions, an accurate diagnosis — often supported by an MRI scan — is important to identify the exact nature and extent of the damage and to guide the most appropriate treatment.

Treatment

Cartilage can't heal itself, making it one of the most complex areas of knee surgery. Thanks to advances in regenerative treatment and bio-materials, several effective techniques are now available:

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

The right choice depends not on preference, but on the type of defect. A surface chondral lesion — where cartilage is damaged but the underlying bone is intact — can usually be resurfaced directly, using AutoCart or occasionally ACI. A larger osteochondral defect, where bone loss extends beneath the cartilage, needs bone reconstructed alongside it — here, an osteochondral allograft is usually the better option. Lesion size, depth, and bone involvement are assessed on MRI and confirmed at arthroscopy to guide the decision.

Frequently asked questions

Not exactly. A cartilage injury is usually a focal, localised area of damage — often from a specific incident. Osteoarthritis is more widespread degeneration across the joint that develops over time. That said, an untreated focal cartilage injury can raise the risk of developing osteoarthritis later on.

Mr Barkatali will start with a physical examination and history of how the injury occurred. An MRI is the primary imaging tool used to assess cartilage, since it shows soft tissue detail that X-rays can’t. In some cases, the injury is only fully confirmed during arthroscopic surgery.

Cartilage injuries are commonly graded on a scale from I to IV based on how deep the damage goes — from mild softening of the surface, up to a full-thickness defect that exposes the underlying bone.

Because cartilage has no nerve endings, damage to it isn’t always painful on its own — pain often comes from surrounding structures reacting to the injury. This means symptoms can be vague or inconsistent, and imaging plays a bigger role in reaching a diagnosis.

No. Smaller or less severe injuries (Grade I–II) are often managed first with physiotherapy, activity modification, and sometimes injections. Surgery is generally considered for larger defects, Grade III–IV injuries, or when symptoms persist despite conservative care.

Since cartilage has limited ability to heal on its own, an untreated injury can gradually worsen — leading to more surface breakdown and an increased risk of developing osteoarthritis in that joint over time.

You can’t fully prevent them, but you can lower your risk by maintaining a healthy weight, building strength around your joints, using proper technique in sport, and addressing any joint alignment issues early with a specialist.

You should see a knee specialist if you have persistent joint pain, swelling, catching, or a sense of instability — particularly after an injury, or if symptoms aren't improving with rest. Earlier evaluation generally means more treatment options are still on the table.

Please use the link below to make an enquiry and we will be in touch to book an initial appointment with Mr Barkatali.

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