Page 60 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.2 The foal and developing animal 35

VetBooks.ir 1.61 1.62

Fig. 1.61 A 2-week-old Clydesdale foal with a left Fig. 1.62 Neonatal dysmature Thoroughbred foal
hindlimb fetlock varus that has been present since with a ‘windswept’ appearance due to a right carpal
birth. Manipulation revealed marked mediolateral valgus and a left carpal varus. There was carpal joint
joint instability in the left fetlock compared with the instability in all planes on manipulation and carpal
right. bone hypoplasia on radiography.

Differential diagnosis Management
Acquired ALDs. In most cases, when newborn foals demonstrate mild
to moderate ALDs, no treatment is required other
Diagnosis than restricted exercise. In patients with cuboidal
The clinical history of a deformity present at bone hypoplasia the use of a tube cast is generally
birth, or shortly thereafter, and the clinical find- advisable (see below). In foals with carpal or tarsal
ings are diagnostic. Radiographs of the affected deformities of mild or moderate severity, it is usu-
area will confirm the exact nature of the problem. ally recommended that a farrier carries out correct
Radiographs (lateromedial and dorsopalmar/ trimming (i.e. removing any excessive lateral [valgus]
plantar) with long plates to allow visualisation of or medial [varus] hoof growth) at 2–4 week inter-
the long bones proximal and distal to the deformity vals. Patience will usually be rewarded by a gradual
should be taken. Lines drawn on the radiographs improvement with time. However, in foals with mod-
through the mid-points of the long bones proxi- erate or more severe fetlock varus/valgus, a more
mal and distal to the affected area should intersect proactive approach is required because the window of
within the affected joint and will allow the angle opportunity for limb correction is quite small (i.e. up
of deformity to be measured. In some cases, there to 12 weeks of age). Similarly, foals with more extreme
are hypoplastic bones present within the joint deformities of the carpus or tarsus should be man-
(Fig. 1.63). Stressed views may be useful where aged more proactively by surgery (see under Acquired
joint laxity is suspected. musculoskeletal abnormalities, p. 49).