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Doctors Discover New Ligament in Knee

Many already know about the four ligaments in the knee- medial collateral, anterior cruciate, posterior cruciate, and lateral collateral.  However, according to a New York Times article, doctors in Belgium have identified a fifth ligament in the knee called the anterolateral ligament (A.L.L.).  This ligament was originally speculated about in the 19th century by a French surgeon named Paul Segond.  While Segond did note evidence of its presence and function, he failed to name it, and its presence was forgotten.

File:PaulSegond.jpg; (US Public Domain Tag)


However, it has been discovered again and given a proper name.  The A.L.L. on the outside, front portion of the thighbone and continues down to the beginning of the shinbone.  This placement allows it to stabilize the knee and prevent it from collapsing inward.  Previously, doctors thought that the A.L.L. was just a continuation of the illiotibial band, but it is clear now that it is a completely different entity.

A few years ago, Dr. Claes and his colleagues noticed that some patients that had underwent and recovered from A.C.L. surgery had problems with their knees collapsing.  He guessed at the existence of a new ligament and searched for the ligament in donated knees; he easily found it.  Now doctors are beginning to practice procedures for torn and sprained A.L.L.s.  Thanks to Dr. Claes’ rediscovery of Segond’s original hypothesis, doctors will now be able to fully treat all ligaments in the knee.

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  1. segolene

    Great article! I can definitely relate to this because last year I tore my ACL, so it is interesting to know that doctors have discovered another ligament called A.L.L. Its placement is also important in that it stabilizes the knee and prevents it from collapsing inward. I am sure many knee reconstructive surgery patients will be interested to know more about the new A.L.L ligament. Check out this article: It gives further information about the ligament and has a nice picture of the interior of the knee as well.

  2. biolabski

    Wow, Paul Segond sounds like a really cool guy! It’s impressive that he knew so much about the knee in 1879 when people have just identified this ligament in 2013. After many experiments on cadavers, he described a “Segond fracture” that is an avulsion fracture to the knee. This means that soft tissue tear off bits of bone of the lateral tibial condyle of the knee. He was an amazing doctor who studied medicine in Paris. He founded obstetrics and taught gynecology in Paris. To read more about this amazing individual and all he contributed to science, go here:

  3. termitelover

    Good to see that knee injuries can be fully operated on now that the ALL has been identified.

  4. biolivcious

    Wow! What amazing discovery! I really believe this will change orthopedics. I can’t believe that this problem was just addressed as knee surgery is a very common practice. This article has an awesome picture and does a good job of describing the function of this new found ligament.

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