Positive first response from medical community...

If you read through the reference given in the previous chapter, you will know by now that there are a number of possible surgical techniques that may benefit someone with joint cartilage damage in the knee. To help surgeons decide which procedure to do, a number of flowcharts (or 'algorithms') have been developed. The surgeon can estimate the depth of the damage and the width of the damaged area, and ask the patient questions about their lifestyle and age. Then by referring to the flowchart, the surgeon will have a fairly good idea of what surgery is likely to benefit the patient.

Both of these techniques involve taking a small amount of healthy cartilage from the patient, sending it to a laboratory to be grown as a tissue culture and then returned to the patient for implant.

In ACI the defect is sealed over with a membrance sewn over the hole, and the cells are injected behind the membrane as a suspension.

In MACI the cells are grown onto a collagen scaffold or 'matrix' in the laboratory, and then the cell-rich scaffold is sewn into place to fill the cartilage defect.

ACI stands for 'autologous chondrocyte implant'