Chondral fracture of the adolescent knee is very rare because of anatomical characteristics. We experienced chondral fracture occurring in both knees of a fourteen years old boy belonging to a volley ball club. Arthroscopic examination revealed white free bodies and chondral defect of the medial femoral condyles in both knees. The free bodies were removed and the area showing chondral defect were treated with drilling. Histologically, the free bodies were mainly composed of degenerated articular cartilage with partial fibrillation and dystrophic calcification but no osseous structure was seen.
