Articular Cartilage Defects
Simon Roberts is a Consultant Orthopaedic and Sports Injury Surgeon. Mr Roberts' caseload consists entirely of sports injuries and trauma, although he doesn't do routine joint replacement surgery. The majority of his work is minimally invasive surgery of the knee, shoulder and ankle for problems of joint instability, ligament and cartilage problems and joint surface defects. Mr Roberts treats elite & professional sportsmen in football, rugby league and rugby union. The Oswestry orthopaedic team has provided treatment for players from most of the Premiership football and Super League rugby teams over the last decade.
One of your areas of expertise is related to the treatment of damage to the joint surface of the knee, the so called articular cartilage defects. How do these injuries occur and what is the normal progression of these injuries?
"The joint surface of the knee is perfectly designed to have shock absorbing properties and very low friction. Injuries can occur either as a result of chronic overload or from a one off injury. It is very important before considering treating articular cartilage defects that this is considered, in that if the cause of the damage has not been addressed then it is very unlikely that filling the defect will be successful.
"The natural history of these lesions has been rather poorly documented. It is undoubtedly true that they are commonly incidental, particularly if they are small, and we have no evidence that any of the specific treatments we have actually affect the long term outcome for the knee. Of course we hope that we are improving the long term prognosis, but the evidence just isn't there as yet. The treatment that we are offering is very much for the symptoms which a patient is suffering here and now."
What are the treatment alternatives for articular cartilage defects?
"Surgery is not the only option for articular cartilage defects and in addition to addressing the possible causes, optimising the musculature around the knee can be helpful. Some modifications of activities or technique as well as (in the non-sporting population) weight loss. Anti- inflammatory drugs in short courses can be helpful and I think there is quite good evidence that the symptoms from low grade articular cartilage problems can be helped by dietary supplements such as Glucosamine. Intra articular injections of steroid are being used much less often, but the rather more expensive visco-supplementation injections are becoming more popular.
"From the surgical point of view there are three groups of treatments which we can offer to restore the articular surface. These are the micro fracture technique which Dr Richard Steadman has pioneered. Osteochondral grafting ("mosaicplasty") which involves taking a section of articular surface from elsewhere in the knee or from a cadaveric (deceased) donor and using this to plug the defect, or the tissue engineering technique of autologous chondrocyte transplantation (transplanting cartilage generating cells that are produced in the lab from the patient’s own tissue)."
The Robert Jones and Agnes Hunt Hospital are leading the way in new techniques for the treatment of articular cartilage defects and early arthritis of the knee. Could you explain what Autologous Chondrocyte Transplantation is and how is can help articular cartilage defects?
"Autologus chondrocyte transplantation is a procedure whereby a small specimen is taken of the articular cartilage of the knee which is subsequently taken off into the laboratory and cultured in a test tube so that the cells multiply. This means that by taking a small biopsy of the surface a much larger surface defect can be filled. A second operation is necessary to insert the cultured cells, usually about 3 weeks later. This is no longer an experimental technique and has national NHS approval for use as part of a well organised research study. In Oswestry, we are able to culture these cells on site in the hospital rather than having to send them away to commercial enterprises abroad."
You are collaborating in the ACTIVE research project which is examining Autologous Chondrocyte Transplantation / Implantation Versus Existing treatments for isolated knee joint surface injuries. Could you explain what this means and what the aims of the study are?
"The ACTIVE research project is a very exciting development funded by the Medical Research Council. It is a pragmatic randomised trial whereby patients in whom we are not sure of the best treatment get either autologous chondrocyte transplantation or whatever we would have offered the patient had ACT never been invented. Patients are carefully assessed preoperatively and then followed up to see if we can pin down which treatment is best and in particular if there are groups of patients which are more or less likely to benefit from this expensive treatment."
How can people with articular cartilage defects take part in the ACTIVE study?
"There is a nationwide network of surgeons who have been trained to provide the treatment and who are feeding data in to be analysed in Oswestry. More details of hospitals and surgeons involved can be seen on www.active-trial.org.uk and from my web site www.sportsinjurysurgery.com."
