medial and lateral aspects), which, when combined with arthroscopy provides
the most efficient definition of the soft tissue injury. Gamma scintigraphy and,
in some limited centres, MRI or CT, are alternatives.
Ultrasonography is a very useful technique to image the peri- and intraarticular soft tissues of the stifle, but its usefulness is limited to the patellar
ligaments, the collateral ligaments of the femorotibial joints and the medial
and lateral horns of the medial and lateral menisci respectively. Meniscal
tears are classified according to their orientation and extent. The cranial and
caudal portions of the femorotibial joints are more difficult to image and
ultrasonographic recognition of pathological changes in the cruciate
ligaments, meniscal ligaments and cranial horns of the menisci continue to
elude us in many cases.
During a scintigraphic examination, lateral, caudal and sometimes flexed
cranial images are obtained of the injured stifle and the contralateral normal
stifle for comparison, on standing, sedated patients for 120 seconds each.
Movement correction of the image is particularly useful for scintigraphic
examination of the stifle. In our clinic, this technique, though rewarding for the
identification of acute skeletal damage, has been less sensitive in the
diagnosis of soft tissue injuries that accompany traumatic arthritis of the stifle.
Specific stifle injuries
In a survey performed in 1994, Dyson reported the incidence of different
injuries to the stifle in Event horses with the following order of decreasing
frequency:
(I)
bruising with or without haemotoma
(II)
fractures of the tibial tuberosity or crest
(III)
fractures of the base of the patella
(IV) fractures of the medial pole of the patella
(V)
fractures of the lateral trochlear of the femur
(VI) cruciate ligament injury
(VII) meniscal (ligament) injury
(VIII) patellar ligament injury
(IX) medial collateral ligament injury
(X)
other fractures of the tibia or femur
I Bruising
Bruising with or without haematoma was by far the most common injury
encountered. When Sporthorses hit a fence, trauma to the cranial aspect of
the stifle is common. Bruising in this area results in haematoma of the cranial
periarticular tissues, characterised by a fluctuant swelling which is
compressible and heterogenous in echogenicity on ultrasound. The horse
does not usually unduly resent flexion or other manipulation of the stifle but
lameness can be severe. These cases should also be evaluated using skyline (cranioproximal-craniodistal oblique) radiographs for possible medial pole
fractures of the patella, which can be easily missed on standard radiographs.
The early response to treatment is often a helpful indicator of the severity of
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
64