In this episode, Marc and Mo are joined by special guests Drs. Hans Kreder, Joseph Schatzker, and Marvin Tile, for a discussion on the history of the AO, the importance of mentorship, and the development of (1) the Schatzker classification system for tibial plateau fractures and (2) the Pennal-Tile classification system for pelvic fractures. Subspecialties: • Orthopaedic Essentials • Trauma Keywords: Orthopaedics, orthopedics, JBJS, OrthoEvidence, Order of Canada, AO, Sunnybrook, Maurice Müller, OTA, residency, fellowship, John Charnley, Schatzker classification, tibial plateau fracture, Pennal-Tile classification