top of page

Cartilage Injury

AdobeStock_390586273.jpeg

  • Articular (joint) cartilage is the smooth, white tissue that covers the ends of bones where they meet to form joints. In the knee, it allows the thigh bone (femur), shin bone (tibia), and kneecap (patella) to glide smoothly against each other during movement. The meniscus is also made of cartilage, but a different type (fibrocartilage)

  • An articular cartilage injury refers to damage to this smooth surface, and we refer to these single areas as cartilage lesions. They may affect just the cartilage layer (chondral), or the underlying bone also (osteochondral), with treatment of the two usually very different. General loss of cartilage over a large area usually refers to arthritis.

    • Acute trauma – a direct blow or twisting injury (e.g., during sports)

    • Repetitive use – especially in athletes and manual labourers

    • Joint abnormalities – such as patellar (kneecap) instability or alignment issues

    • Pain in the knee, often in a specific location, and especially during activity

    • Swelling (effusion) or stiffness

    • Clicking, locking, or catching sensation

    • Decreased ability to participate in sports or weight-bearing activities

    • Physical examination 

    • MRI scan – Provides detailed images of cartilage, but also of the other structures within the knee that could be causing symptoms

    • Arthroscopy – ‘Keyhole’ surgery can be used for diagnosis, but is usually used in treatment

  • When one stands, walks or runs, your bodyweight passes through your knee. This is transmitted from your hip to the floor, and usually passes roughly through the centre of the knee. If one is very varus (‘bow-legged’), then this weight passes more to the inner side of the knee. If one is more valgus (‘knock-kneed’), this weight-bearing axis passes more to the outer side.  Proper knee alignment and joint stability are essential for maintaining healthy cartilage. If the knee is malaligned or unstable, certain areas of cartilage may bear more weight than they should, leading to excessive wear and injury.

    ​

    Why it matters:

    • Even with successful cartilage treatment, underlying alignment or stability issues must be corrected to prevent further damage.

    • In some cases, additional procedures like ligament reconstruction or osteotomy (bone realignment) may be recommended alongside cartilage repair to ensure long-term success.

  • Non-surgical management

    • Activity modification – Avoid high-impact activities.

    • Physiotherapy – Strengthens the muscles around the knee and improves joint function.

    • Medications – Pain relief with anti-inflammatories (NSAIDs).

    ​​

    Surgical treatment

    Surgical options depend on the size, location, and depth of the defect

    ​

    Cartilage only (‘chondral’) lesions

    ​

    • Debridement/chondroplasty - this involves an arthroscopic (keyhole) procedure to smoothen rough edges, and remove damaged cartilage. A scar-like cartilage (fibrocartilage) will usually fill the defect and improve symptoms, but this is not the same as articular (hyaline) cartilage.

    • Autologous Matrix-Induced Chondrogenesis (AMIC) - this procedure aims to grow replacement cartilage in the defect that is more like ‘hyaline’ cartilage - the type of cartilage that makes up the joint surface. It involves debridement of the damaged area of cartilage back to the bone, and implantation of a collagen-matrix patch. Cartilage cells then grow onto the patch, creating a mix of fibro- and hyaline type cartilage. For more information click here.

    • Autologous Chondrocyte Implantation (ACI) - This procedure aims to recreate hyaline (articular) cartilage within the knee. It is performed over two separate operations:​​​​

    1. The first is performed arthroscopically, and involves removing a small amount of cartilage from a non-weight bearing area of the knee. This is the ‘donor’ site. This cartilage is then used to extract cartilage making cells. These cells are then grown in a lab for approximately three weeks.

    2. The second procedure involves re-implantation of the cartilage cells to the damaged area of the knee. This is usually through a small, open incision, and combined with a collagen matrix (like AMIC).

    ​​

    Cartilage and bone (‘osteochondral’) lesions

    ​

    • Osteochondral Autograft Transfer (OATS) - where the underlying bone is also affected, this procedure involves taking a ‘cartilage-bone unit’ from a non-weight bearing part of the same knee, and transplanting it into the defect. It is performed as a procedure with an open incision, rather than arthroscopically (keyhole).
    • Osteochondral Allograft Transplantation - this is a procedure used to treat large defects involving the cartilage and underlying bone. It involves taking the cartilage-bone unit from a donor (cadaveric), and implanting it into the defect. 

    ​

    Additional procedures may be performed to correct alignment or instability if needed.

    • Recovery varies from weeks to several months, depending on the treatment

    • Physiotherapy is crucial to restore strength, movement, and function

    • You may need to limit weight-bearing or wear a brace for a period of your recovery

    • The outcomes for each treatment are different, and you surgeon will talk to you specifically about these. Generally, early treatment of smaller defects often leads to better outcomes.

    • While complete restoration of the joint cartilage is difficult, treatment aims to reduce pain, improve function, and delay or prevent arthritis.

    • Untreated injuries can progress to osteoarthritis over time.

bottom of page