Toddler's fractures or childhood accidental spiral tibial (CAST) fractures are bone fracture

Bone fracture

A bone fracture is a medical condition in which there is a break in the continuity of the bone...

s of the distal (lower) part of the shin bone (tibia

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....

) in toddlers (aged 9 months-3 years) and other young children (less than 8 years). The fracture involves the distal third to distal half of the tibia, is undisplaced and has a spiral pattern. It occurs after low-energy trauma

Physical trauma

Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

, sometimes with a rotational component.

Diagnosis

Typical symptoms include pain

Pain

Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

, refusing to walk or bear weight and limping -bruising and deformity are absent. On clinical examination, there can be warmth and swelling over the fracture area, as well as pain on bending the foot upwards (dorsiflexion

Dorsiflexion

Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...

). The initial radiographical images

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....

 may be inconspicuous (a faint oblique line) and often even completely normal. After 1-2 weeks however, callus

Fibrocartilage callus

A fibrocartilage callus is a temporary formation of fibroblasts and chondroblasts which forms at the area of a bone fracture as the bone attempts to heal itself...

 formation develops. The condition can be mistaken for osteomyelitis

Osteomyelitis

Osteomyelitis simply means an infection of the bone or bone marrow...

, transient synovitis or even child abuse

Child abuse

Child abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...

. Contrary to CAST fractures, non-accidental injury typically affect the upper two-thirds or midshaft of the tibia.

Other possible fractures in this area, occurring in the cuboid

Cuboid

In geometry, a cuboid is a solid figure bounded by six faces, forming a convex polyhedron. There are two competing definitions of a cuboid in mathematical literature...

, calcaneus, and fibula, can be associated or can be mistaken for a toddler's fracture. In some cases, an internal oblique radiography and radionuclide imaging can add information to anterior-posterior and lateral views. However, since treatment can also be initiated in the absence of abnormalities, this appears to have little value in most cases. It could be useful in special cases such as children with fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, those without a clear trauma or those in which the diagnosis remains unclear. Recently, ultrasound

Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 has been suggested as a helpful diagnostic tool.

Pathophysiology

The proposed mechanism involves shear stress

Shear stress

A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...

 and lack of displacement due to the periosteum

Periosteum

Periosteum is a membrane that lines the outer surface of all bones, except at the joints of long bones. Endosteum lines the inner surface of all bones....

that is relatively strong compared to the elastic bone in young children.

History

The condition was initially recognised by Dunbar and co-workers in 1964. A new terminology has been proposed, which defines toddler's fracture as a subset of childhood accidental spiral tibial (CAST) fractures.