Page 375 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

350 CHAPTER 1

VetBooks.ir to 6 weeks. Damage to the associated tendon or liga- In these areas the digital extensor tendons lie directly
between the skin and bone and are easily damaged
ment and surrounding tissues (i.e. bone, neurovas-
cular structures, etc.) should be specifically treated.
direct trauma. The tendon and underlying tissues
Adhesions are best prevented by early aggressive or severed. Tenosynovitis may be a consequence of
anti-inflammatory treatment, followed by in-hand may also be affected. Haemorrhage in the sheath
walking as early as possible (when oedema has induces severe inflammation. If tenosynovitis, par-
receded). Controlled exercise is instituted within ticularly from chronic infection, is left untreated, it
2–3 weeks of injury. Cryotherapy and bandaging may lead to chronic synovial thickening and fibrosis,
are continued for several weeks to prevent recurrent restrictive adhesion formation and eventually partial
bleeding and extension of the inflammation into the carpal or tarsal joint motion restriction (ankylosis).
tendon. Chronic adhesions can cause recurrence of Idiopathic tenosynovitis is of unknown origin.
the lesion, persistent pain and lameness, and aggra- There is increased synovial fluid production, but the
vation into overt tendinopathy. In this case, surgical synovial membrane is not thickened and no pain is
adhesiolysis may be warranted. observed.

Prognosis Clinical presentation
The prognosis is usually good in the absence of Partial tendon damage usually causes mild to moder-
complications. It is more guarded in the presence of ate lameness. With complete rupture, depending on
restrictive adhesions and/or tendinopathy. which tendon is affected, the horse may be unable to
extend the carpus, tarsus, fetlock and/or digit. With
EXTENSOR TENDON INJURIES LDE or CDE rupture the animal will tend to buckle
AND TENOSYNOVITIS over at the fetlock and drag the toe. This gradu-
ally improves as the horse learns to compensate by
Definition/overview flicking the limb forward. If the LaDE tendon is not
Injuries to the extensor carpi radialis (ECR), lateral affected, the horse can regain normal extensor tone
digital extensor (LaDE) and common digital extensor within a few days or weeks.
(CDE) tendons in the forelimb or to the tibialis crani- With trauma not inducing an open wound, there
alis (TC), fibularis (peroneus) tertius (FT), lateral dig- is a painful swelling and thickening due to local hae-
ital extensor (LaDE) and long digital extensor (LDE) matoma, periosteal contusion and tendon damage.
tendons in the hindlimb are common in horses of all In the dorsal carpal or tarsal area, the main sign is
breeds and ages. They occur through direct trauma to tendon sheath swelling, characterised by fluid dis-
the dorsal aspect of the limb or may occur spontane- tension arranged longitudinally over the dorsal/
ously in foals. Tenosynovitis of their synovial sheaths dorsolateral aspect of the joint and interrupted over
is usually a consequence of trauma, with or without the bones because of compression by the transverse
damage to the tendon they surround. Idiopathic teno- retinacula (Fig. 1.692). Horses are usually mark-
synovitis, characterised by non-painful sheath effu- edly lame, except in idiopathic tenosynovitis, where
sion without evidence of inflammation, is occasionally there is neither pain nor heat. There may, however,
encountered. Spontaneous rupture of the CDE tendon be some mechanical restriction in joint mobility. In
is recognised in the foal (see p. 41). Septic tenosynovi- chronic traumatic cases the swelling becomes firm
tis of the extensor sheaths is frequently encountered and non-painful, but carpal or tarsal passive flexion
due to open or penetrating wounds. is painful and markedly restricted.
Open skin wounds expose the tendon and/or
Aetiology/pathophysiology periosteum. If the tendon is partially severed, the
Trauma occurs through kicks or hitting jumps, gates frayed tendon ends are usually visible at the wound
or wire fences. Wounds and contusions are most edges. If it is totally severed, the cut ends tend to
common over the dorsal aspect of the distal limb, retract for several centimetres proximally and dis-
particularly in the metacarpus/metatarsus, dorsal tally, so that the tendon is no longer visible, and
distal radius and carpus or dorsal tarsal regions. the periosteum is exposed and often stripped