The Segond fracture is a type of
avulsion fracture
An avulsion fracture is a bone fracture which occurs when a fragment of bone tears away from the main mass of bone as a result of physical trauma. This can occur at the ligament by the application of forces external to the body (such as a fall ...
(
soft tissue
Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes.� ...
structures pulling off fragments of their
bony attachment) from the
lateral tibial plateau of the
knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
, immediately below the articular surface of the
tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
(see photo).
Clinical significance
Because of the high rate of associated ligamentous and meniscal injury, the presence of a Segond or reverse Segond fracture requires that these other
pathologies must be specifically ruled out. Or more pragmatically, the orthopaedic team assume that the presence of Segond fracture equals ACL rupture, as the correlation is close to 100%. Increasingly, reconstruction of the ACL is combined with reconstruction of the anterolateral ligament when this associated pathology is present. The long-term benefit of an associated Anterolateral Ligament (ALL) reconstruction at the time of ACL surgery is not known. Attention and research is also being paid to a Lateral extra-articular Tenodesis (LET) instead of ALL.
Diagnosis
Segond and reverse Segond fractures are characterized by a small avulsion, or "chip", fragment of characteristic size that is best seen on plain
radiography
Radiography is an imaging technology, imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiog ...
in the
anterior-posterior plane. The avulsed fragment of bone may be very difficult to see on the plain
x-ray
An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...
exam, and may be better seen on
computed tomography
A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...
.
MRI
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
may be useful for visualization of the associated
bone marrow edema of the underlying tibial plateau on fat-saturated T2W and STIR images, as well as the associated findings of ligamentous and/or meniscal injury.
History
Originally described by Dr.
Paul Segond in 1879
after a series of
cadaver
A cadaver, often known as a corpse, is a Death, dead human body. Cadavers are used by medical students, physicians and other scientists to study anatomy, identify disease sites, determine causes of death, and provide tissue (biology), tissue to ...
ic experiments, the Segond fracture occurs in association with tears of the
anterior cruciate ligament
The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are called "cruciform" ligaments, as they are arranged in a crossed formation. In ...
(ACL) (75–100%) and injury to the
medial meniscus (66–75%), lateral capsular ligament (now known as the Anterolateral ligament, or ALL), as well as injury to the structures behind the knee.
A rare, mirror image of the Segond fracture has also been described. The so-called "reverse Segond fracture" can occur after an avulsion fracture of the tibial component of the medial collateral ligament (MCL) in association with posterior cruciate ligament (PCL) and medial meniscal tears.
Segond fracture is typically the result of abnormal varus, or "bowing", stress to the knee, combined with internal rotation of the tibia. Reverse Segond fracture, as its name suggests, is caused by abnormal valgus, or "knock-knee", stress and external rotation.
Originally thought to be a result of avulsion of the medial third of the lateral collateral ligament, the Segond fracture has been shown by more recent research to relate also to the insertion of the iliotibial tract (ITT) and the anterior oblique band (AOB), a
ligament
A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...
ous attachment of the
fibular collateral ligament
The lateral collateral ligament (LCL, long external lateral ligament or fibular collateral ligament) is an extrinsic ligament of the knee located on the lateral side of the knee. Its superior attachment is at the lateral epicondyle of the femur ( ...
(FCL), to the midportion of the lateral tibia and to be associated with avulsion by the anterolateral ligament (ALL).
[Roberts CC, Towers JD, Spangehl MJ et-al. "Advanced MR imaging of the cruciate ligaments". Radiol. Clin. North Am. 2007;45 (6): 1003–16, vi–vii.]
References
External links
{{Fractures , state=collapsed
Bone fractures