Cartilage Repair and Transplantation

Articular, or hyaline, cartilage is a firm, rubbery material covering the ends of bones, creating a smooth surface for motion. It reduces friction and acts 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.

Cartilage repair or transplantation: What treatments are available?

I perform 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 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 into the defect by open surgery.

Osteochondral autograft transplantation (OATS)

OATS procedure involves transferring healthy cartilage and subchondral bone from an area of the joint that does not bear weight 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. I typically perform 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.