Osteochondral lesions of the ankle (i.e. lesions affecting the articular cartilage and the underlying bone, usually due to trauma), are often treated in a "biological" way in young patients: damaged tissues are regenerated by using the patient's own stem cells. 

However, this option is only valid for young patients with a limited size of lesion. Biological cartilage reconstruction is no longer effective, with increasing age, in case of excessively large and deep lesions or failed surgical treatments.