We report a case of compression fracture of anterior margin of medial tibial plateau and medial femoral condyle combined with the posterior cruciate ligament and posterolateral corner disruption. A thirty-seven-year old male had undergone the left knee injury 6 months before. The physical examination revealed positive posterior drawer test and tibial dial test, which evidenced the posterior cruciate ligament and posterolateral corner insufficiency. The plain lateral knee radiographs showed a marginal fracture of the anteromedial tibial plateau and a dimpling on the adjacent part of the medial femoral condyle. On arthroscopy, there were no gross tear of the cruciates, but the posterolateral capsule disclosed stigmata of stretching injury with multiple petechiae and scarring. The compression fracture on the anteromedial side and the stretching injury on the posterolateral side altogether support the mechanism of hyperextension pivoting on the anteromedial side of the knee joint. A small bony lesion around the knee joint should be inspected rigorously with an assumed mechanism of injury for it may herald major ligamentous injury.