Thursday, November 07, 2013 Going ALL-In for Newly Discovered Ligament The mystery of a 134-year-old anatomical "enigma" has finally been solved with the announcement of a new knee ligament. Described in 1879 only as a "pearly resistant fibrous band," the newly named anterolateral ligament (ALL) could affect tibial rotation and the pivot shift phenomenon, according to researchers. The presence of the ligament was verified through examination of 41 cadaveric knees, which, with 1 exception, included the ALL. A recounting of the research (abstract only) that led to the discovery was published in the October 2013 issue of the Journal of Anatomy, and word quickly spread to major news organizations such as the Huffington Post and Time. Researchers describe the ALL as a "well defined structure" that is situated "at the prominence of the lateral femoral epicondyle, slightly anterior to the origin of the lateral collateral ligament." It follows an oblique course to the anterolateral aspect of the proximal tibia, with its insertion on the tibia "grossly located between Gerdy's tubercle and the tip of the fibular head, definitely separate from the iliotibial band (ITB)." While the authors cite the need for more research on the ALL, they hypothesize that the ligament plays the role of a stabilizer for internal rotation, and speculate that the ALL could play a part in "rotary knee instability patterns witnessed in many [anterior cruciate ligament] deficient knees."