Articular Cartilage

 

These pictures taken at a knee arthroscopy show smooth, intact articular cartilage on the left and a defect in the articular cartilage of the knee on the right. The pink area is bone beneath the articular cartilage which is being treated using the ‘microfracture’ technique (see below).

Articular cartilage (hyaline cartilage) is the white smooth surface of joints which makes a low friction bearing, lubricated by a thin film of joint fluid.  It has a limited capacity to heal when injured and trauma to the knee is now recognised to be a potent cause of knee osteoarthritis.  Surgery has a role in treating articular cartilage damage and is broadly divided into three categories.

  1. Microfracture. A technique which causes bleeding from the bone beneath the area of damage to cause scar tissue to form in the damaged area
  2. Mosaicplasty.  Plugs of articular cartilage are transplanted from another area of the knee joint to fill the area of damage
  3. Articular cartilage

transplantation (ACT).  Small pieces of articular

cartilage are taken from the knee and grown in culture, before being reintroduced into the area of damage.  Two operations are required. 

Unfortunately, none of these techniques provide a reliable solution to repairing damaged articular cartilage.  ACT shows promise and almost certainly tissue culture holds the key to findings way to regenerate areas of articular cartilage damage and reduce the risk of osteoarthritis.


 
The rough and irregular joint surface indicates that osteoarthritis has developed within the knee



RWN’s view

ACT or similar techniques may be the future, but are not commonly available at the moment.  A combination of microfracture and mosaicplasty are used to repair isolated defects in articular cartilage caused by an injury.   The healing process is slow, over six to 12 months, but there will be an improvement in the short/medium term approximately 80% of cases, but it is unsure at this stage if the longer term risk of osteoarthritis is reduced by these procedures. Much research is taking place to explore the most effective way to ‘regrow’ articular cartilage when it has been damaged. These techniques are used to treat knee damage before arthritis has developed, they are not suitable for treating established knee arthritis.