Cartilage preservation and regeneration procedures
A fair amount of research is going into cartilage (gristle) preservation and regeneration. Frankly, presence or absence of cartilage (gristle) is the difference between normal and arthritic joints. There is not one technique or procedure that satisfactorily addresses this issue. The basic principle is to have a joint that is well-aligned (straight) for patient’s anatomy and has normal movement for the cartilage regeneration procedures to be successful.

Our practice is to preserve cartilage as much as possible. The flaps of relatively healthy cartilage can be attached back using biological glue or bioabsorbable pins. This may be combined with microfracture or retrograde drilling to enable the stem cells to come in contact with the healing area. In scenarios where cartilage is deficient in focal areas various cartilage regeneration techniques are employed. These include;

• Microfracture where specific instruments make holes perpendicular to articular cartilage defect to allow stem cells to differentiate into chondrocytes. The technique was popularised after good results were reported from Steadman-Hawkin clinic.
• Autologous Chondrocyte Implantation (ACI) involve harvesting cartilage cells arthroscopically, which are then cultured in lab to increase their number and implanted back in the defect covering it with lining membrane of the bone. The second part of the operation usually involves open surgery.
• Matrix Induced Cartilage Implantation/Transplantation (MACI/ MACT) is similar to ACI, however the cartilage cells are embedded on to a membrane that is implanted in the defect.
• Mosaicplasty is another procedure where plugs of cartilage and underlying bone are taken from a non-weight bearing part of the joint and are arranged into the damaged area.
• OATS (Ostechondral Autograft Transfer System)or mega OATS are similar to mosaicplasty, however the plugs of cartilage and bone tend to be much larger and hence the defect is filled with one or two plugs usually.
• Osteochondral Allograft is used for large defects of cartilage and underlying bone. These grafts are taken from a donor from the tissue bank and are shape matched to the patient’s joint. This involves open surgery to fix them in place. The size can be variable depending on the defect that is being addressed.

Meniscus
The two menisci in the knee are C-shaped shock absorbers, sandwiched between the thigh bone on the top and leg bone at the bottom. These are subjected to loads many times the body weight of the individual during walking, running and jumping. The very nature of the meniscus function, which is shock absorption and to increase the contact area of the knee joint, puts them at increased risk of injury. The tear of the meniscus causes pain, swelling, clicking and occasionally renders the knee locked in a certain position.

Meniscus tears are diagnosed clinically and confirmed on MRI scan. The arthroscope (key-hole surgery) is particularly good at dealing with meniscus injury. At our Practice, the ethos is to preserve meniscus and hence we aim to repair the torn meniscus unless it is degenerate or deformed, thus rendering it unsuitable for repair. In the later case a partial trimming of the meniscus is undertaken using specialized instruments. The repair of the meniscus is carried out arthroscopically, however certain types of tears may require a small open incision as well. The aim is to have a stable repair. More recently the meniscus transplant and implants have been used in a select patient population.