Other Factors in Deciding Indications
For the new repaired area to grow properly and to last it is important to consider treating other problems that may be affecting the knee. If the knee is out of alignment (bowlegs or knock-knees) then this can be corrected with an osteotomy operation cutting through and realigning the bones. If the knee joint is unstable due to a ligament rupture happening at the same time or different time to the original injury then the ligament (e.g. anterior cruciate ligament) can be rebuilt at the same time. Also it is best if the meniscus cartilage is intact to protect the new surface and if not then it is possible to rebuild this using synthetic scaffold substitutes or a meniscal allograft transplant. Details of these procedures are outside the scope of this booklet.
There are a number of other conditions where the procedure does not help or has limited ability to help, including osteonecrosis, chondrocalcinosis, advanced osteoarthritis, rheumatoid arthritis and after total meniscectomy where there is no meniscus cartilage to protect the joint surface cartilage. Chronic viral infections such as hepatitis and HIV are also contraindications to this procedure.
Not all people with defects in their cartilage lining are suitable for MACI repair – the recovery period is long and it takes a well motivated patient to apply themselves to the rehabilitation.