The Segond fracture is an avulsion fracture of the lateral tibial plateau and is considered pathognomonic for anterior cruciate ligament (ACL) injury. A case of a Segond fracture occurring with a clinically, radiologically and arthroscopically intact ACL is presented. This was associated with a serious injury to the posterolateral corner requiring surgical reconstruction. Relevant literature is discussed, and the suggestion is made that, whilst an ACL rupture may be the most commonly noted soft tissue component associated with a Segond fracture, the clinician should have a high level of suspicion for other serious soft tissue injuries. Level of evidence V.