Page 397 - The Veterinary Care of the Horse

float around the joint space. Slab fractures are larger and extend throughout the whole length

of the bone. These most often occur in the third carpal bone.
VetBooks.ir CAUSES

• The fragments of bone break off in response to repeated concussion and overloading of

the front of the carpal bones.
• Back-at-the knee conformation may predispose to this type of injury.

• Tired horses are most likely to sustain injury.

• Poor racing and training surfaces.
• Working at very fast speed.

• Foot imbalance causes uneven distribution of forces within the limb.

CLINICAL SIGNS

These depend on the type of fracture. They include:

• variable degrees of lameness: small, undisplaced fractures may cause slight lameness,
whereas large chip or slab fractures can be very painful and cause severe lameness

• heat and swelling over the front of the knee

• a tendency to stand with the knee slightly flexed
• reduced flexion and severe pain on flexion in horses with large chip or slab fractures

• pain on palpation of the front of the joint.

DIAGNOSIS

The diagnosis is made on the results of clinical examination, intra-articular analgesia and
radiography. Multiple X-ray views of the carpus, including some with the knee flexed, are

required to show up the different bone surfaces. Repeat views may be necessary 10–14 days
later as some fractures do not show up initially. Arthroscopy is helpful as the joint surfaces
and ligaments within the joint can be seen and the damage is often more extensive than that

seen on the X-rays. Scintigraphy is useful for detecting early stress fractures.

TREATMENT
Treatment may be surgical or conservative. Small or incomplete chip fractures that are not

displaced may be treated conservatively with an extended period of box rest and gradual
introduction of controlled exercise. Larger chips or thin slabs should be surgically removed

as soon as possible after the injury has occurred to minimize the risk of subsequent
degenerative joint disease (DJD). Larger slab fractures are treated by screwing them back in