Page 160 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 135

VetBooks.ir Clinical presentation 1.239
Horses usually present with a unilateral low-
grade chronic lameness with thickening/heat over
the palmarolateral/palmaromedial fetlock region.
In cases with acute tearing, more overt lameness
and pain localised to this region may be evident.
Examination of the suspensory ligament may
reveal involvement of additional structures in the
condition.

Differential diagnosis
PSB fracture; palmar/plantar annular ligament injury/
avulsion; suspensory ligament branch injury.

Diagnosis
Regional perineural analgesia may be required to
localise the lameness. Radiographic assessment of
the fetlock is important, particularly oblique radio-
graphic projections highlighting the palmar aspects
of the PSBs. Change in bone density with radiolucent
lines radiating across the sesamoid bone due to lysis Fig. 1.239 Oblique radiographic view of the right
around the vascular channels are usually evident. foreleg fetlock joint of a horse with sesamoiditis
Entheseopathy resulting in bony enlargement may revealing radiolucent lines radiating across the
result in change in shape to the PSB ( usually length- sesamoid bone and bony enlargement resulting in a
ening) (Fig. 1.239). Comparison with the contra- change in shape.
lateral limb is important in determining the degree
of change and to assess the joint for concurrent 1.240
radiographic changes (e.g. OA). Ultrasonography of
the region and suspensory apparatus is also advised
(Fig. 1.240).

Management
Management is aimed at reducing inflammation and
preventing recurrence. Local cold therapy, rest and
NSAIDs with a controlled exercise programme
are warranted. Extracorporeal shock-wave ther-
apy has been used successfully in refractory cases.
Concurrent suspensory ligament injury will also
require appropriate management.

Prognosis
Young racehorses with moderate sesamoiditis
(enlarged vascular canals >2 mm in width) are asso- Fig. 1.240 Transverse ultrasound view of the medial
ciated with reduced performance. The presence of distal suspensory ligament branch insertion onto
radiographic changes with concurrent soft- tissue the sesamoid bone in a case of severe sesamoiditis.
injury (e.g. suspensory ligament injury) is also Note the damaged ligament and the irregular bone
deemed a negative prognostic finding. interface. (Photo courtesy Graham Munroe)