Page 139 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

114 CHAPTER 1

VetBooks.ir 1.198 1.199

Fig. 1.198 Dorsoproximal/palmarodistal oblique Fig. 1.199 Dorsolateral/palmaromedial flexed
view of a foot with collateral entheseopathy at the oblique view of a foot with collateral entheseopathy at
insertion of a collateral ligament (right side of the the origin of a collateral ligament (left of the image).
image). There is focal osteolysis bordered by an There is entheseous new bone formation at the site of
irregular margin of sclerosis at the site of insertion of the proximal attachment of the collateral ligament to
the collateral ligament to the distal phalanx. the proximal phalanx.

Radiographs may be useful to detect the osteo- MR images show increased cross-sectional
proliferative or osteolytic changes that accompany area, irregular contour and increased signal inten-
some cases of collateral entheseopathy. A focal sity of the diseased ligament. In addition, osse-
osseous cyst-like lesion at the insertion can occa- ous abnormalities of the distal or middle phalanx
sionally be seen on a dorsoproximal/ palmarodistal have been seen in approximately 40% of cases,
oblique projection of the foot (Fig. 1.198). including cortical irregularities or defects, osse-
Proliferative entheseopathy is sometimes recog- ous cyst-like lesions and abnormal mineralisa-
nised on oblique radiographs of the foot at the tion or bone oedema associated with the origin
origin of the collateral ligament on the middle or insertion of the diseased collateral ligament
phalanx (Fig. 1.199). Ultrasonography is difficult (Figs. 1.200, 1.201).
and limited to the proximal 25% of the collateral
ligament, and artefacts are common. In one study, Management
ultrasonography had a poor sensitivity for diag- The most important aspect of treating injuries of
nosis of collateral ligament injury in comparison the collateral ligaments of the DIP joint is rest. This
with MRI. should minimally consist of stall rest for 4–6 months.
Increased radionuclide is present at the insertion During this time the foot must be kept level and
site of the ligament on the distal phalanx in bone well balanced to eliminate the most likely cause of
phase scintigraphy of some horses with collateral the injury (i.e. uneven loading of the quarters). For
desmitis or entheseopathy. Although scintigraphy similar reasons, it has been proposed that asymmet-
appears to have a low sensitivity, the specificity of ric shoes for horses with collateral ligament disease
the described patterns of hot spots is high for the should have a double width branch at the side of the
diagnosis of this condition. injury to prevent the foot from sinking excessively