Articular, or hyaline, cartilage is a firm, rubbery material covering the ends of bones, creating a smooth surface for motion. It reduces friction, and helps to act as a ‘shock absorber’. When articular cartilage becomes damaged, it limits the joint’s normal movement and can cause pain. In most cases, articular cartilage cannot repair itself. If damaged areas are not treated, it can worsen and eventually lead to osteoarthritis of the knee.

Cartilage repair or transplantation: who is a candidate?

Cartilage repair or transplantation is a treatment used for otherwise healthy joints, when the damage has not progressed to osteoarthritis. It is often used for patients with damage due to:

  • Injury or trauma, including sports injuries
  • Repetitive use
  • Osteochondritis dissecans and joint developmental abnormalities
  • Congenital abnormalities

Knee imaging showing an osteochondral defect

Knee imaging showing an osteochondral defect

Cartilage repair or transplantation: What treatments are available?

Dr Radic performs most cartilage repair procedures arthroscopically. During arthroscopy, the joint is entered via two small incisions, approximately 1-2cm in length. The smaller cuts allow for a more rapid recovery, with less post-operative pain than traditional surgery. When treating large areas of damage, an ‘open’ technique may be required.


Chondroplasty is performed arthroscopically, and describes smoothing irregular areas of cartilage or removing large flap tears which are causing mechanical obstruction. This is the simplest cartilage repair technique, but does not aid in regeneration of the cartilage surfaces.


This procedure is performed arthroscopically. The goal of microfracture is to stimulate the growth of fibrocartilage in the defect, by creating a new blood supply to the area. During microfracture a sharp awl is used to make multiple holes in the joint surface, allowing bone marrow cells to stimulate fibrocartilage covering of the area.

Autologous Chondrocyte Implantation

Autologous Chondrocyte Implantation (ACI) is a two-stage procedure. During the first stage, a small biopsy of cartilage is taken from a non-weightbearing area of the bone. It is then sent to a laboratory where the cells are cultured and increase in number over a 4-6 week period.

At the second-stage surgery, the cultured cartilage is implanted in to the defect by open surgery.

Diagram demonstrating the autologous chondrocyte implantation (ACI) procedure

Diagram demonstrating the autologous chondrocyte implantation (ACI) procedure

Osteochondral Autograft Transplantation (OATS)

OATS procedure involves transferring healthy cartilage and subchondral bone from an area of the joint that does not bear wait, to the damaged area. It is ideal for lesions up to 20mm in size. The graft is taken as a ‘plug’ of cartilage with underlying bone, thereby maintaining the health of the joint surface. Dr Radic typically performs this procedure arthroscopically, although for some larger lesions an open approach may be required.

Osteochondral Allograft Transplantation

When the damaged area of cartilage is too large for autograft transplantation, the defect can be filled by donor tissue, or a cadaveric graft. The graft is sterilised and matched to the donor, to ensure it is the correct size and curvature for the native joint. It is shaped to fill the defect, and transferred to the joint via an ‘open’ technique.

If you are considering having cartilage repair and transplantation for your knee, make an appointment with Dr Radic to discuss your treatment options.

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Perth Orthopaedic & Sports Medicine Centre
31 Outram Street
West Perth WA 6005

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4 Antony Street
Palmyra WA 6157

HBF Stadium
100 Stephenson Ave
Mount Claremont WA 6010

Kimberley Orthopaedics
36 Frederick St
Djugun WA 6725

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