The Segond fracture is a type of avulsion fracture

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 due to the application forces external to the body or at the tendon due to a muscular contraction that is stronger than...

 (soft tissue

Soft tissue

In anatomy, the term soft tissue refers to tissues that connect, support, or surround other structures and organs of the body, not being bone. Soft tissue includes tendons, ligaments, fascia, skin, fibrous tissues, fat, and synovial membranes , and muscles, nerves and blood vessels .It is sometimes...

 structures tearing off bits of their bony

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

 attachment) of the lateral tibial condyle

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 of the knee

Knee

The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...

, immediately beyond the surface which articulates with the femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

.

History and incidence

Originally described by Dr. Paul Segond

Paul Segond

Paul Ferdinand Segond was a French surgeon who was a founder of obstetrics and the teaching of gynaecology in Paris. He was also an expert on the knee and described the eponymous Segond fracture.- Biography :...

 in 1879 after a series of cadaver

Cadaver

A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....

ic experiments, the Segond fracture occurs in association with tears of the anterior cruciate ligament

Anterior cruciate ligament

The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , based on its anatomical position, it is referred to as the cranial cruciate ligament.The ACL originates from deep within the notch of the distal femur...

 (ACL) (75–100%) and injury to the medial meniscus

Medial meniscus

-External links: *...

 (66–75%), lateral capsular ligament, 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.

Mechanism

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

Ligament

In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...

ous attachment of the fibular collateral ligament

Fibular collateral ligament

-External links:*...

 (FCL), to the midportion of the lateral tibia.

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

Pathology

Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....

 must be specifically ruled out.

Imaging findings

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

Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....

 in the anterior-posterior

Anatomical terms of location

Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

, or "front-to-back", plane. The chip of bone may be very difficult to see on the plain x-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 exam, and may be better seen on computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

. MRI may be useful for visualization of the associated bone marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

 edema

Edema

Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

of the underlying tibial plateau on fat- saturated T2W and STIR images, as well as the associated findings of ligamentous and/or meniscal injury.