Spontaneous Healing of ARticular Cartilage (SHARC)

Osteoarthritis (OA) is a very common disease of the joints, for which in the United Kingdom alone almost 9 million people have sought treatment. This painful disease affects the cartilage and bone inside the joint. Many factors are known to increase the risk of getting osteoarthritis, or the rate at which it gets worse. Very important among these factors is an injury or a defect of the cartilage. It was believed for hundreds of years that cartilage, once injured, does not heal.

Research from the past 10 years is now throwing doubt on this old certainty, as researchers who took regular scans of volunteers over time noted that sometimes these defects come and then go. A Japanese group of surgeons decided to look again after a year to see what had happened to these defects, and noted that about half of them had got better! Cartilage defects in human therefore can heal, but nobody knows how this works.

For many years, our Center has helped patients who have knee cartilage damage by using the patients' own cartilage cells to help repair areas of damaged cartilage. This cell therapy starts by taking a piece of cartilage (10 mm) from the patient's knee, and this created defect always heals after a year. Thus, our proposal is to use our cell therapy patients as a human experimental model of natural cartilage healing using a wide range of techniques including Magnetic Resonance Imaging (MRI), visual inspection of the joint itself during knee joint surgery, examining biopsies of repair tissue down the microscope and measuring various kinds of molecules researchers think are important. The information gathered from these tests will help bridge the gap in our understanding of the mechanisms involved in the cartilage tissue regeneration.

Inclusion criteria

• Being able to provide signed and dated informed consent form.
• Scheduled for one of the following surgical treatments

• Surgery that involves the harvest of cartilage tissue as part of the treatment, thus creating a fresh cartilage defect, which is then left to heal naturally. Examples of such surgery are autologous chondrocyte implantation (ACI) and mosaicplasty.
• Autologous stromal cell implantation (ASCI), as part of the ASCOT randomised clinical trial.

Exclusion criteria

• Inadequate understanding of verbal explanations or written information given in English, or having special communication needs.
• Chronic severe renal insufficiency
• Anything that would preclude the individual's full compliance with or completion of the study.