Depending on the patient’s age, site of injury, the seriousness of the injury and the degree of activity, various therapies are available. Treatment is individualized and tailored to each patient but broadly there are 4 main treatment options.

The four different treatments are outlined below:

Arthroscopic debridement of the knee joint

This is the least drastic treatment, and basically comprises a debridement (washout) of the knee joint. During an exploratory operation (arthroscopy), the damaged cartilage edges are cleaned up and loose pieces of cartilage are removed. This generally relieves the pain and improves mechanical symptoms such as locking. However, this is usually not considered a long-term solution.


The patient undergoes an intervention during which small, cylindrical dowels of bone with healthy cartilage are removed from a lesser weight-bearing section of the joint, the “donor site” (1). Small holes are then drilled at the location of the cartilage lesion, into which these dowels will be located (2). Since it is only possible to remove a limited amount of healthy cartilage and bone from the donor ares, this treatment is only possible for injuries with a maximum area up to 5 cm2. The advantage of the mosaic-plasty technique is that it can be performed in a single procedure. Small cartilage lesions can be treated arthroscopically but usually this operation is performed through a small incision. Complications of the technique include bleeding in the knee joint in 8% of patients while about 3% develop long-term symptoms related to the cartilage defects at the donor site.



Initially an arthroscopy is performed to determine if the lesion is suitable for microfracture. Through key hole surgery small holes are made in the bone using a sharp awl. During this process, the bone plate is perforated, releasing bone marrow cells from the bone, which fills the original defect.

Microfracture is a popular, easy and economical intervention that has been shown to effectively improve knee function. It can be applied during a single step arthroscopic intervention and is considered standard of care for lesions smaller than 2-3 cm2. Shortcomings of the technique include limited hyaline repair tissue3, with the formation of scar tissue.

There is also growing concern about the long-term effects of microfracture on the underlying bone, which may compromise long-term outcomes and limit the success of subsequent cartilage repair procedures.


Autologous Chondrocyte Implantation

Autologous Chondrocyte Implantation is a type of regenerative medicine that uses the body’s own cartilage cells to restore joint cartilage injuries. The regenerated cartilage is usually of better quality than the cartilage that is generated after microfracture. There are very few long term follow-up studies comparing Autologous Chondrocyte Implantation to microfracture. Results so far indicate that clinical results are equivalent6, or to favor Autologous Chondrocyte Implantation7. Most experts in the field believe that Autologous Chondrocyte Implantation may provide better long term outcomes because of the better cartilage quality as compared to microfracture. An Autologous Chondrocyte Implantation treatment comprises two steps, namely arthroscopy and the implantation. The cell culture takes place in between.

Step 1: arthroscopy

During this operation two small incisions are made in the knee. The surgeon removes a bit of healthy cartilage (“biopsy”) from a lesser weight-bearing region of the knee. This material is then used to culture the cartilage cells for re-implantation. When these cells have reproduced sufficiently to fill up the defect, the cells will be implanted in the knee.


Step 2: The implantation

During an open knee operation, the surgeon covers the damaged cartilage with a thin membrane which is sutured and glued in place. The suspension of cultured cartilage cells is then injected under this membrane. After the open-knee surgery, the patient usually remain in the hospital for a few days