October 2009
Mr. Ved Goswami FRCS MS MCh(Orth), Consultant Orthopaedic Knee, Shoulder & Sports Surgeon, discusses the new cartilage transplant technique (ACI) now available at Spire Parkway Hospital.
Background: Traumatic articular cartilage injuries (the joint lining as opposed to the shock absorber inside the joint) in the knee are common and are a frequent cause of pain and loss of function. The articular hyaline cartilage is an avascular tissue and if it is damaged, is unable to repair itself. When these cartilage injuries are full thickness, the potential long term problems include early osteoarthritis and its associated disability. In the past, no satisfactory method to restore hyaline cartilage existed and often a damaged joint surface has signaled the end of an active career. However, a new transplant technique has shown great promise in treating these serious injuries, known as Autologous Chondrocyte Implantation (ACI). Evolution in biotechnology gives us the ability to harvest chondrocytes from the knee and stimulate them to reproduce in the lab. They can then be inserted back into the articular defect with the aim of laying down a hyaline articular matrix.
Procedure: First, the orthopaedic surgeon takes a small biopsy (about the size of two pencil erasers) of healthy cartilage using Arthroscopic technique. These cells are grown in the lab until they are enough to repair defect, usually about 3 weeks. We are now using the third generation of this technology in which the cells are grown onto a Type III collagen membrane known as Matrix Autologous Chondrocyte Implantation (MACI) . In the second stage, the knee joint is opened and after preparation of the defect, the collagen membrane containing the Autogenous chondrocytes is then “sutured or glued” into place with fibrin glue. The cells attach to the bone and multiply to form new hyaline cartilage covering the defect.
Indications: Currently ACI or MACI is indicated for full thickness traumatic lesions greater than one centimeter in size where the matching articular surface is in good condition and the patient is less than 55 years or age. Trials are currently underway in some osteoarthritic OA defects, if the original cause for the OA can be reserved. It is important that the patient has a neutrally aligned limb, else the graft will fail. At times, a simultaneous osteotomy maybe necessary to correct the limb alignment prior to the MAC
Outcome: Currently ACI-MACI is still undergoing investigation as to its benefits but non-controlled trials at 5-8 years have good to excellent outcomes in 75-90 % of patients. The most promising aspect of the treatment is that it can produce hyaline or hyaline-like articular cartilage, which has the potential to restore normal joint surface.