Page 404 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 379

VetBooks.ir Diagnosis bursitis with this condition. Gastrocnemius tendon-
itis lesions resemble those observed in the digital
Clinical examination
Lameness is associated with focal swelling over the
vial thickening and distension of the gastrocnemius
distal common calcaneal tendon area. This is, how- flexor tendons and there is usually associated syno-
ever, not always evident and regional perineural anal- bursa. The lesions tend to be diffuse with a mottled
gesia may be necessary to confirm the site of pain. pattern rather than a discrete hypoechogenic lesion.
Tendonitis of the origin of the gastrocnemius Entheseopathy/avulsion at the femoral origin may
muscle is difficult to confirm clinically. Anaesthesia be difficult to diagnose, as the tendon is very short
of the stifle joints is normally negative. Radiography and muscle fibres may resemble a lesion. A haema-
may show new bone remodelling over the caudal dis- toma may be obvious in acute cases, characterised by
tal femoral metaphysis. Scintigraphy is a useful tool focal enlargement and a discrete anechogenic struc-
for detecting entheseopathy. ture, usually organised into several loculated cavi-
Rupture of the SDFT proximal to the hock gives a ties. In chronic cases, entheseopathy with marked
characteristic dropping of the hock during the stance bone remodelling may be seen. Ultrasonography is
phase, but this may be difficult to observe because of useful to confirm partial or complete rupture of the
the associated severe lameness. Complete rupture is SDFT (Fig. 1.750). It is not necessary for complete
confirmed through the pathognomonic ability to flex common calcaneal tendon rupture as the clinical
the hock passively without flexing the stifle. signs are pathognomonic.

Ultrasonography Management
Ultrasonography is necessary to confirm the pres- Calcaneal tendon disease is best treated conserva-
ence of tendon disease. Deep calcaneal (tarsal) tendi- tively with box rest with controlled exercise. It may
nopathy is characterised by marked enlargement and take a fairly long time (up to 12 months) before a
decreased echogenicity of the deep tarsal tendons horse with gastrocnemius tendinopathy can resume
(Figs. 1.748, 1.749). These are difficult to image full work. Recurrence is very common.
for an inexperienced operator and care should be SDFT rupture is treated with complete box rest,
taken not to confuse focal oedema or gastrocnemius and some limb support (full-limb cast or splints) is

1.748 1.749

Figs. 1.748, 1.749
Transverse (1.748) and
sagittal (1.749) sonograms
of the common calcanean
tendon (arrows) showing
severe increase in size and a
heterogeneously decreased
echogenicity of the deep
part of the tendon. These
images are typical of deep
tarsal tendonitis.