Page 119 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

94 CHAPTER 1

VetBooks.ir duration can result in marked contraction of the hoof PEDAL OSTEITIS
capsule, but it should be continued during return to
exercise to avoid the risk of recurrence.
Acute articular fractures in the median plane in Definition/overview
The term pedal osteitis has been used as a radio-
adult horses have been successfully treated with graphic description of a pattern of generalised
internal lag screw fixation. Healing time is signifi- resorption of bone around the solar margin of the
cantly shorter (3–6 month) but complications include distal phalanx. In a broader sense, osteitis of the
infection, screw irritation and step-formation at the distal phalanx refers to any reaction of the bone in
articular surface invariably leading to OA. The OA response to a primary insult. Such potential insults
that occurs in some horses following both conserva- to the bone are blunt external trauma, penetrating
tive and surgical treatment of articular fractures may injuries with or without infection, solar bruising,
require treatment with intra-articular steroids and/ abscesses, lamellar inflammation, keratomas and
or a palmar digital neurectomy for temporary resolu- surgical implants.
tion of lameness, but is usually a poor outcome factor.
Small fractures of the extensor process are Aetiology/pathophysiology
removed arthroscopically. Larger fractures may Radiographic signs of osteitis include localised oste-
be reduced by internal fixation with a lag screw or olysis, sclerosis, bone fragmentation, bone seques-
removal of the fracture fragment. Fragments of up tration and new bone formation. Generalised bone
to 15–20% of the distal phalanx have been removed resorption around the solar margin of the distal
successfully without complications. phalanx is known to occur following certain inflam-
Solar margin fractures that are not associated with matory processes or injuries that induce inflamma-
infection are treated with rest and NSAIDs. In foals tion (e.g. laminitis and hoof wall avulsions). It is also
less than 6 months of age, stall rest or small round seen commonly in horses with flat soles, particularly
pen turn out is typically sufficient to allow sponta- those horses demonstrating recurrent bruising, and
neous healing. Glue-on cuff shoes may be used but underrun heels. It is therefore a known sequela to
must be monitored carefully due to the potential for some inflammatory diseases in the soft tissues adja-
rapid development of an abnormal, contracted foot cent to the distal phalanx and a suspected sequela to
shape. others. What is not known is whether generalised
Fractures associated with infection are treated in bone resorption around the solar margin can occur
the same manner as septic osteitis of the distal pha- following a primary inflammatory response in the
lanx (see p. 96). bone. Until it is established that this occurs, it is
best considered as a radiographic sign rather than
Prognosis a definitive diagnosis and even then, primary pedal
The prognosis is good for solar margin fractures and osteitis, the definitive diagnosis, will have to be dif-
non-articular fractures of the wing of the distal pha- ferentiated from secondary pedal osteitis, the clini-
lanx. About 50% of horses with body or wing frac- cal (radiographic) sign.
tures treated with rim shoes will return to soundness
after 6–12 months. The prognosis for articular frac- Clinical presentation
tures of the body of the distal phalanx is good in Pedal osteitis is most commonly identified in the
horses less than 3 years old. For older horses with forelimbs and is frequently bilateral. It is frequently
articular fractures treated conservatively, the long- identified in horses with mild to moderate lameness
term prognosis is fair to guarded in horses not used in the forelimbs but is also a common incidental
for racing, but variably guarded to poor, unless finding.
treated successfully by internal fixation, for race-
horses. The prognosis is good for small extensor Differential diagnosis
process fractures that are removed arthroscopically Other causes of mild to moderate forelimb lameness;
and fair for removal of larger fracture fragments. navicular disease; laminitis; bruising; imbalance.