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Cartilage is the smooth lining on the surface of bone that plays a role in joint lubrication and shock absorption. As we get older, the water content in cartilage decreases and other changes in it makes it vulnerable to injury. It can get worn out from traumatic sports injuries or a gradual “wear and tear” from years of impact loading of the joint.
Full thickness cartilage injuries can progress to full blown arthritis if left alone. Our goal in cartilage regeneration procedures is to repair the defect using a variety of techniques depending on the size of defect, location of defect and other deformities if present.
Microfracture
• This is one of the most popular cartilage repair techniques that can be done arthroscopically (keyhole) and as a day surgery procedure
• It involves making small holes within the defect and the aim is to liberate small numbers of stem cells from the underlying bone marrow to repair the defect
• To improve the results of this technique, we now augment it with post-operation injections of hyaluronic acid or platelet rich plasma
Autologous Chondrocyte Implantation (ACI) or Cartilage Transplantation
• 2-stage procedure
• The first stage involves arthroscopic (keyhole) harvesting of chondrocytes (cartilage cells) from a non weight-bearing area of the knee
• The harvested cells are then grown in culture and multiplied
• The second stage takes place 3 weeks later when sufficient chondrocytes have been cultured
• These are then implanted into the defect and there is no risk of rejection since the cells are patient’s own
• In the first generation technique, a patch of tissue is stitched over the defect and cultured cells are then injected underneath this patch which is then sealed up. Current 3rd generation techniques do not require stitching of this patch as the cells are already grown onto the patch itself which is then fitted into the defect and held with special tissue glue
Mesenchymal Stem Cells in Cartilage Regeneration
Stem cells are specialised cells that have the potential to become bone, cartilage or fat forming cells under the right circumstances. Our medical director has been involved in the study of mesenchymal stem cells (from bone marrow) for both cartilage and bone repair since 2004. These are adult stem cells and we do not deal with embryonal stem cells in clinical practice currently.
Currently, the use of stem cells for use in human cartilage repair in Singapore is still classified as being experimental and must be done under the auspices of an ethical-board approved trial. This means that patients have to meet strict inclusion and exclusion criteria before they can be enrolled.
Dr Lee was the Principal Investigator of two grants using stem cells in cartilage repair: “A Phase One Multi-Center Study of a Novel, Minimally-Invasive Technique of Repairing Large Cartilage Lesions in the Human Knee” and “A Multi-Centre Randomised Controlled Trial Evaluating a Novel Minimally-Invasive Technique of Cartilage Repair in the Human Knee Using Autologous Mesenchymal Stem Cells and Hyaluronic Acid”. The second trial is still ongoing and recruiting patients and Dr Lee will perform the surgeries in Mount Elizabeth or Gleneagles Hospital as part of the multi-center study. This trial aims to investigate the efficacy of microfracture combined with injections of mesenchymal stem cells.
The inclusion criteria for this trial :
• Patients with symptomatic cartilage injury of the weightbearing condyles of the knees
• Age 21 to 55, inclusive
• Normal axial alignment
• Stable knees. Previous ligament reconstruction who are currently stable are allowed into the study
• Willingness to follow the post-operation protocol and rehabilitation
• Able to understand and willing to sign the consent form |
