In the past, the treatment of cartilage injuries has had its limitations. Today, cartilage regeneration using the patient’s own stem cells has made the treatment of complex cartilage injuries possible, especially at the knee joint. These degenerative changes to the joints occur when there is a breakdown of articular cartilage.
Articular Cartilage Regeneration With Stem Cells
What is articular cartilage?
The articular cartilage has a specialized function to resist compression. It has no blood supply, no lymphatic drainage and no nerve supply. This means that the articular cartilage's individual cells and their surrounding tissue also do not have any blood supply. Therefore, they will not be able to respond to any injury unless the underlying subchondral bone is penetrated.
Partial and full thickness injury
If there is only partial thickness injury to the articular cartilage (where the injury does not penetrate to the subchondral bone) there will be no response to the injury.
On the other hand, if there is a full thickness injury, which penetrates into the subchondral bone, the injury will trigger the bone marrow stem cells to initiate a process of cartilage repair.
Symptoms of pain, swelling and the occasional giving way of the knee joint, may suggest damage to the articular cartilage. Progressive degeneration of the articular cartilage will eventually result in the development of osteoarthritis.
These types of injuries are more likely to occur in sporting individuals. If there are areas of chondral injury, it will be detrimental to the joint and affect the performance of the individual. Multiple areas of chondral injuries may also occur such as knee instability due to an Anterior Cruciate Ligament deficient knee.
In chondral injuries to the knee joint, non-surgical treatment which includes physiotherapy and medication, do not allow healing to the cartilage defects. On the other hand, current established surgical options are not entirely satisfactory. However, there are a few existing surgical procedures which can help.
Existing surgical procedures
Autologus chondrocyte implantation
This implantation involves two surgical procedures.
The first is arthroscopic harvesting: a minimally invasive surgery to harvest normal looking cartilage from the patient. This cartilage will then be sent to the lab for growing of individual chondrocytes.
Once the chondrocytes have multiplied, an open surgery is performed to facilitate implantation. The process of culturing chondrocytes is expensive and will cost approximately RM25,000. This does not include the cost of the arthroscopic harvesting and the second open surgery.
Other surgical methods
Another surgical option in treating articular cartilage injury is osteochondral autogenous transfer which usually requires an open procedure for harvesting normal cartilage and transplanting a cylinder of bone to cartilage defect areas.
A simpler and more attractive option involves subchondral drillings into damaged areas, which will allow the formation of a messenchymal blood clot to resurface the cartilage defect. Unfortunately the repaired tissue is mainly fibrous cartilage in nature and not hyaline cartilage, which is the preferred and original cartilage.
Recent evidence of stem cells cartilage regeneration
Recent studies initiated by doctors from Kuala Lumpur Sports Medicine Centre (KLSMC), the orthopaedic department of University Putra Malaysia and veterinary hospital showed that it was possible to regenerate a better cartilage by injecting a combination of bone marrow stem cells and hyaluronic acid into the defective areas following subchondral drillings.
Pilot study on clinical patients
A pilot study on clinical patients commenced in March 2007 at KLSMC, whereby cartilage defects seen during arthroscopic surgery were treated by subchondral drillings. The drillings into the bone marrow forms a blood clot scaffold. Post-operatively, the patient undergoes peripheral blood stem cells harvesting, and a week after surgery, a mixture of peripheral blood stem cells together with hyaluronic acid is injected into the affected joint weekly for a period of 5 weeks.
A second look arthroscopic performed on patients showed evidence of hyaline cartilage regeneration. Regular MRI scans at intervals showed satisfactory healing of the chondral defects including the subchondral bone. This newfound innovative procedure allows the subchondral drillings to be applied to both isolated and multiple areas of chondral defects. Best of all, no second surgery or open surgery is required as in the case of autologus chondrocyte implantation.
A brighter future for orthopaedics and other surgeries
In addition to regenerating articular cartilage, stem cells can be employed for other applications in orthopaedic surgery such as diabetic foot ulceration, injuries to the tendons and ligaments, fractures and areas of the bone loss or experiencing delayed union. Stem cell therapy can also be extended to nerves and muscles injuries.
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