Introduction

Autologous chondrocyte implantation (ACI) is another means of repairing damaged cartilage.¹ It is based on harvest of 200 to 300 mg of cartilage from a less loaded area in the knee. The cartilage is sent to a lab for processing. The cartilage is digested; the isolated chondrocytes are expanded in vitro during 2 to 3 weeks. The expanded final amount of cells is re-sent to the doctor as a suspension. The cells are to be injected into the defect covered with a membrane, periosteum (first generation), or collagen membrane (second generation).

Technical Overview

Cartilage Harvest

The cartilage is harvested from a less loaded weight-bearing area such as the upper medial femoral condylar area or similar on the lateral upper femoral trochlear area. Also the notch area is easy to use for harvest (Fig. 9C-1).

FIGURE 9C-1 The suggested locations for harvest of cartilage for cell culture.

By long-time experience, the amount that has been suggested for cartilage harvest is 200 to 300 mg. Such an amount is about a strip with 10 mm in length and 5 mm in width.

Use a ring curette or sharp gouge like a Wiberg raspatorium. Go deep down to cartilage-bone junction and leave a thin attachment of the strip. This strip may then be grasped with a forceps and ripped off with a gentle movement and taken through the portal to be put into a tube with saline. You may need two to three similar strips (Figs. 9C-2 and 9C-3).

FIGURE 9C-2 With the raspatorium, go down deep to bone to obtain a strip of cartilage for cell culture. Leave the last part of the strip still attached. Use a grasping forceps to rip off the strip and pull out from the knee portal.

FIGURE 9C-3 About two to three strips are harvested and put into a transport medium.

For the cell culture, the staff needs to take 10 6-ml test tubes with blood to be processed into serum for the subsequent cell culture.

Blood test tubes and harvested cartilage are sent to the cell laboratory that the hospital has a contract with.