The anterolateral ligament is the newest anatomical find in the orthopedic world of medicine to date. Dr. Steven Claes and Dr. Johan Bellemans are two orthopedic surgeons from the University Hospital of Leuven who spent four years researching pivot shifts in the knee and why they still seem to occur even after the anterior cruciate ligament (ACL) had been successfully operated on.
The knee as a whole is an extremely complex and delicate anatomical instrument that is usually subject to wear and tear especially among athletes. Extensive research and new surgical techniques are continuously being tried out in order to keep the knee as healthy and as functional as possible for as long as is realistically allowed.
As it happens, the theory that an extra ligament could exist on knee has been around since 1879 when a french surgeon named Paul Segond documented his findings. This hypothesis was further examined by the Belgian surgeons from Leuven, in order to solve the mystery as to the continuing complaint of joint pivot shifts, who managed to positively confirm the theory.
The anatomy of the anterolateral ligament (ALL)
It has been debated since if the origin is indeed where it has been previously stated or whether it comes from the lateral femoral condyle, which remains to be seen.
This anatomical structure is thought to be present in up to 79% of the world’s current human population and functions to stabilize the knee during medial rotation. Therefore, when a patient presents with a pivot shift and an anterior cruciate ligament (ACL) injury, it is now known that this occurrence is more than likely due to an anterolateral ligament (ALL) injury.
A Segond fracture, first described by french surgeon Paul Ferdinand Segond (1851-1912), is a type of avulsion fracture involving the lateral condyle of the tibia.
This type of fracture is traditionally associated with tears of the anterior cruciate ligament of the knee (ACL), but increasingly also with the anterolateral ligament described above.
This type of fracture is most often caused by 'bowing'/varus stress to the knee joint, combined with medial rotation of the tibia.
Segond fractures are characterised by the presence of isolated bony material, known as an avulsion, from the lateral tibial condyle.
The bony fragment itself is often best visualised by CT (computed tomography), however MRI (magnetic resonance imaging) may also be useful by means of characterisation of ligamentous/meniscal injury, as well as bone marrow oedema of the underlying fractured bone.