Page 348 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 323

VetBooks.ir (DBLPN), desmoplasty (longitudinal tenotomy) has encountered bilateral lesions. It is most common
in the forelimbs but can also occur in the hindlimbs,
and microdrilling (osteostixis). Recent studies have
shown that neurectomy of the DBLPN alone or
palpable pain but the localising signs, as for proximal
combined with fasciotomy provided a good prog- especially in Standardbred racehorses. There may be
nosis for return to full work with 79–89% of cases desmopathy, are subtle.
being sound and in use after several months. This is,
however, a palliative treatment, and the lesions may Differential diagnosis
persist or worsen if work is reinstituted too soon. It As for proximal SL desmopathy. Main differential is
should therefore be associated with a period of rest stress (fatigue) fracture of the palmar cortex of the
with controlled exercise as described above. In severe third metacarpus.
cases, microdrilling or microfracture, desmoplasty
(longitudinal tenotomy) and concurrent injections of Diagnosis
stem cells, PRP or UBM have been suggested during Clinical examination
the surgery, although there is limited data to support Based on the signs described above. Diagnostic anal-
this currently. gesia is usually necessary.

Prognosis Radiography (see Figs. 1.603, 1.604)
The prognosis for return to the same level of per- Detecting the avulsed fragment may be difficult,
formance is good in the forelimb (90%), but guarded particularly in the hindlimb. There may be marked
to poor in the hindlimbs (22%), with conservative sclerosis in the proximopalmar/plantar aspect of the
treatment alone. In the hindlimb, an initial treat- third metacarpus/metatarsus. The fragment may be
ment with rest and shock-wave therapy may be visible as a displaced mineralised object immediately
attempted, but surgery is often recommended as a palmar/plantar to the bone cortex, often distal to
primary treatment, or certainly if medical therapy the projection of the origin of the SL (2–4 cm dis-
has failed. Chronic or recurring injuries respond tal to the carpometacarpal/tarsometatarsal joint). In
less well to treatment and the presence of osseous other cases, a thin straight or curved lucent line may
pathology appears to negatively affect the prognosis. be visible on dorsopalmar/plantar projections, less
A straight hock/low fetlock conformation appears to commonly on lateral radiographs.
be a poor prognostic sign and a contraindication for
surgical treatment. Ultrasonography (see Figs. 1.619, 1.620)
There is always accompanying damage to the dorsal
AVULSION FRACTURE OF THE ORIGIN aspect of the SL near its origin and in some cases,
OF THE SUSPENSORY LIGAMENT severe proximal desmopathy may be present concur-
rently. The fragmentation may be obvious with a dis-
Overview placed fragment forming a hyperechogenic interface
Although the aetiology may be similar to that of within the dorsal part of the ligament. Sometimes,
proximal desmopathy, this is considered a separate the lesion may be subtle with an irregular margin
condition. It should not be confused with stress (callus formation or periosteal new bone) delineat-
fractures of the proximal palmar metacarpal bone, ing a bony interface slightly proud of the rest of the
which is not related to the soft tissues. This condi- metacarpal/metatarsal bone surface. This should not
tion affects all types of horses but is most common be confused with entheseopathy, which presents as
in Standardbred racehorses. irregular new bone usually more proximally.

Clinical presentation Scintigraphy
There is usually a sudden-onset, mild to severe lame- Scintigraphy is a sensitive technique to detect avul-
ness, often during or shortly after exercise or racing. sion fragments, particularly in acute or subacute
The condition is most often unilateral but the author cases.