What are Articular Cartilage Lesions?
Articular cartilage is the tough smooth tissue which covers the ends of bones forming joints. Due to the smoothness and the presence of joint fluid (synovial fluid) they provide an almost frictionless movement at the joint surface. This helps to reduce the effort needed to move the joint.
What causes these?
The cartilage can be damaged due to trauma and sporting injuries.
It can also be damaged due to a selective wear and tear process. In children the cartilage lesion can occur secondary to a minor trauma due to condition called osteochondritis dessicans (literally meaning ‘drying up of the cartilage’).
How are they diagnosed?
The assessment includes examination followed by further MRI imaging. Quite often arthroscopy is required to precisely diagnose the severity of damage.
How are they treated?
These are difficult problems to treat and there are multiple treatment methods which are still relatively recent. They can all be grouped together as cartilage regeneration procedures.
Cartilage regeneration techniques -This is a name given to a variety of specialised surgery which aims to rebuild the damaged joint cartilage. So long as the damage is in a limited area it can be treated with one of the cartilage regeneration techniques. Once a diagnosis is reached, the cartilage lesion is managed by one of the following techniques:
Autologous chondrocyte implantation:
In this technique, patients own cartilage cells are harvested from healthy cartilage in other part of the knee and grown in the laboratory into multiple cells (in millions). This process takes a couple of months. These cells are then implanted into the defective cartilage.
Mosaicplasty:
In this technique, cylindrical blocks of cartilage and bone are harvested from the non-weight bearing part of the knee.
The defect in the joint cartilage is then prepared and the harvested blocks are implanted in. This technique is still considered the standard to assess other newer treatment options.
Microfracture:
This technique is used when the lesion is in a small area but of a severe nature. The bone underneath the affected cartilage is drilled with specialised instruments to expose bleeding surface. The area eventually heals by forming a combination of scar tissue and cartilage.
Chondroplasty:
This is utilised when the cartilage lesion is of less severity. It involves smoothening superficial irregularities in the cartilage. This is achieved with motorised shavers or radiofrequency probe.
These techniques aim to regenerate the cartilage but the formed cartilage (fibrocartilage) is usually of a different character and may be slightly less resistant than the original joint cartilage (hyaline cartilage).