Surgical Anatomy in ACL Tears

Routine surgical exposure of the lateral compartment is no longer a common practice, as it was in the past. Therefore, most of the reports describing the surgical anatomy of the anterolateral capsule and ligament date back to the seventies and eighties, before the spread of arthroscopy, which dramatically changed knee ligament surgery. All these old-fashioned studies reported a prevalence of injuries in the anterolateral capsule occurring in as much as one hundred percent of all acute ACL tears. Thanks to our attitude towards acute ACL tears, which includes a comprehensive early surgical approach to either ACL or anterolateral ligament (ALL) tears, we reported a prevalence of macroscopically identifiable ALL injuries in approximately 90% of cases. Four types of tears were identified, which included stretching of the ALL, sometimes extending towards the posterolateral capsule (incomplete tears), complete ALL tears usually located below the lateral meniscus, and avulsion bony injuries (Segond’s fracture), the latter occurring in less than 10% of cases. We speculate that Segond’s fracture is only the tip of the iceberg of injuries, which usually affects the midsubstance ALL.