Page 400 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 375

VetBooks.ir frequent. Early treatment and aggressive, vigorous or penetration injury by sharp or pointed objects,
although it may also be iatrogenic (surgical interven-
postoperative care can lead to success in some cases.
In acute injuries, box rest, bandaging and applica-
tion of a cast or splint preventing limb flexion may tion, intrasynovial injection).
be effective. Clinical presentation
In most cases, complete luxation will allow the A characteristic soft swelling is visible on both sides
tendon to become stabilised in its dislocated posi- of the point of the hock, extending proximally along
tion. Although a mechanical lameness may remain, the common calcaneal tendon (Fig. 1.743). There is
particularly with lateral luxation, the horses are pain usually moderate to severe lameness, in part because
free and may be able to return to their previous level of synovial pressure causing mechanical impairment
of performance. to hock flexion, and because of pain in inflammatory
Bursoscopy of the calcaneal bursa to debride the cases. In septic cases, lameness is severe and there is
torn ligament branch and damaged surface of the associated oedema. In chronic cases, diffuse thick-
SDFT has recently been described. This allows for ening can make identification of the bursa difficult.
stabilisation of the ligament in its luxated position
and has been associated with a good prognosis. Diagnosis
Clinical examination
Prognosis Diagnosis is based on observation of a fluid swell-
The prognosis is guarded for luxation, both laterally ing on the plantar aspect of the hock, with typical
and medially, with many horses remaining mechani-
cally lame. Some animals will still be able to perform
normally despite slight gait impairment. 1.743

CALCANEAL BURSITIS

Definition/overview
The calcaneal bursa is a synovial pouch located deep
to the SDFT as it courses over the tuber calcis of the
fibular tarsal bone (calcaneus). It is a large bursa that
extends from the distal crus between the SDFT and
gastrocnemius tendons to the distal tarsus. It is nor-
mally a virtual cavity containing very small amounts
of fluid, but it will become distended in conditions
affecting the SDFT (trauma, tears, luxation), calca-
neus or any surrounding tissues. A study has shown
that the bursa extends around the SDFT distal to
the tuber calcis in 39% of cases to form a subcuta-
neous recess and that it always extends around the
gastrocnemius tendons to form a smaller gastroc-
nemius bursa. Effusion may occur spontaneously
without overt inflammation, although this is uncom-
mon. Inflammatory bursitis may be due to trauma
to the point of the hock, to the SDFT, to the distal Fig. 1.743 This photo of the medial hock shows
part of the gastrocnemius tendons or to the calca- swelling of the calcaneal bursa just dorsomedial to the
neus itself. This leads to synovial membrane inflam- common calcaneal tendon. This was associated with
mation and fluid effusion. Septic tenosynovitis is injury to the gastrocnemius tendon. (Photo courtesy
most commonly due to wounds to the plantar hock Sue Dyson)