Chondral lesions of the knee can affect the young, active population, thereby causing severe morbidity and loss of function pain and swelling. Although numerous approaches have been described in the literature, full restoration of hyaline cartilage has yet to be demonstrated. Specifically, larger, full-thickness cartilage defects remain a challenge. For cases of cartilage defects that are larger than 10mm in size, the BioUni knee transplantation of fresh cartilage (through a bone and cartilage transplant) is an excellent option to restore these defects. The unique aspect of this technique and the BioUni system is that it provides an “oval” graft and donor site, rather than a “round” traditional cylindrical technique. We have found this to be particularly helpful in lesions greater than 10-12 mm as many of these are oval in shape. This is my technique for biologic unicompartmental osteochondral allograft transplantation for the treatment of large femoral condyle articular cartilage defects.