Fractures in the Horse. Группа авторов

Proximal sesamoid Palmar flexor region Medial sesamoid abaxial mid‐body subchondral bone [38] [156] Proximal phalanx Sagittal groove [157] [158] Pelvis Ilial wing Pubis [159] [137] [160] [161] [162] Tibia Distomedial Caudoproximal Caudal diaphyseal Proximolateral under the head of the fibula [163] [164] [148] Tarsus Dorsolateral third tarsal bone [165] [166] Lumbar spine L5–L6 vertebral junction [136]

The most common physeal fracture in horses is a Salter–Harris type II [175]. These have been reported in the third metacarpal and metatarsal distal physes, distal femoral physis and proximal tibial physis [175–177]. Physeal fractures of the proximal tibia have a typical pattern of type II with a lateral metaphyseal corner [179]. Type IV injuries tend to be unstable and many require internal fixation [180]. Bridging of the physis during internal fixation of physeal fractures should be avoided if possible as it may result in premature closure and subsequent development of angular limb deformity [180]. Type V injuries are rare, and are often not initially radiographically detectable, but manifest as a progressive angular limb deformity [176].

Table 3.2 Features and qualifiers of features applicable to fracture description.

      Source: Stover [170]. Reproduced with permission of Sage Publication.

Feature	Qualifier	Description
Location	Epiphysis	Fracture involves the end of a long bone
	Physis	Fracture involves an open physisa
	Metaphysis	Fracture involves a region of the bone adjacent to the physis on the side closest to the diaphysis
	Diaphysis	Fracture involves the central region of a long bone
Direction	For example, proximodorsal to distopalmar	Direction(s) of the fracture line(s) is (are) described from proximal to distal unless the direction of propagation is known (e.g. MCIII/MTIII condylar fractures progress from distal to proximal)
Plane	For example, transverse, oblique, longitudinal, sagittal and dorsal	Orientation of the predominant fracture line
Configuration	Transverse	Fracture courses perpendicular to the longitudinal axis of the bone
	Longitudinal	Fracture courses parallel to the longitudinal axis of the bone
	Oblique	Fracture courses along a flat plane obliquely through the bone (i.e. not parallel to a transverse or longitudinal plane)
	Spiral	Fracture has a spiral component
	Butterfly	Fracture has transverse and oblique components
Extent	Complete	Fracture courses completely through the bone, dividing it into two or more separate fragments
	Incomplete	Fracture does not course completely through the bone
Displacement	Nondisplaced	Fracture fragments remain in anatomic apposition
	Displaced	Fracture fragments separated, angulated or overriding, and no longer in anatomic apposition
Complexity	Simple	One fracture line dividing the bone into two separate fragmentsb
	Intermediate	May have one or two sizeable bony fragments (e.g. complete mid‐diaphyseal metacarpal/metatarsal fracture with a butterfly component)
	Complex	Multiple fracture lines and ≥3 bony fragments or greater comminution
Joint involvement	Non‐articular	The fracture does not extend through an articular surface
	Articular	The fracture courses through an articular surface
Contamination	Closed	The skin overlying the fractured bone is intact and not penetrated by the injury
	Open	The skin has a wound over the fracture that introduces contamination and increases the risk of infectionc
Other	Avulsion	A fracture fragment that distracted from the parent bone by tension through a soft tissue (tendon and ligament) attachment
	Slab	A biarticular fracture with the fracture plane perpendicular to the articular surfaces of the parent bone
	Condylar	Fracture involves a condyle

      ^a Physeal fractures are further described according to the Salter–Harris classification scheme.

      ^b One or two minor bone chips do not change the definition of a fracture as simple.

      ^c Open fractures are further classified according to [171].

      Completeness

      A complete fracture occurs when a bone is separated into two or more parts. Complete fractures may divide a bone into individual segments, or a fragment of bone can be completely separated from the parent bone. An incomplete fracture typically involves only one cortical or subchondral compacta without propagating to another cortical or articular surface. Additional subcategories of incomplete fractures include fissure fractures, where a crack extends into but not through one cortex (seen commonly in the tibia and radius), and greenstick fractures, where the cortex loaded in tension fractures and the opposing cortex bends, such as those occasionally seen in the middle of the metacarpal/metatarsal diaphysis in foals [181].

      Complexity

      Fracture complexity must be considered