This case report describes the management of a 14-year-old soccer athlete with osteochondritis dissecans of the lateral femoral condyle and a subsequent grade IV chondral lesion in the femoral trochlea. The initial treatment with fresh osteochondral transplantation resulted in osteointegration, pain resolution, and restored functionality. During rehabilitation, a secondary trochlear lesion developed and was treated with a combination of micro-fragmented autologous adipose tissue and a collagen membrane. The patient showed significant improvements in functional scores.