This study describes a modified AMIC technique consisting of perforations according to Pridie, rather than microfractures, and the covering of the focus of the lesion with a biological collagen patch enriched with bone marrow blood drawn through the knee itself. This technique allows advantages of both the Pridie technique and the in situ proliferation of mesenchymal cells beneath a biological collagen membrane, 'augmented', with bone marrow blood. The collagen membrane forms the roof of a 'biological chamber', and serves to protect and contains the stem cells as they differentiate into chondrocytes, which will form a healthy regenerative cartilage.