Meniscal tears have been classified into three categories arthroscopically:
Grade I
confined to the cranial ligament of the meniscus
Grade II
tears extending from the cranial ligament of the meniscus into
the meniscus but where the entire tear is visible
macroscopically.
Grade III
Grade IV
a tear in the meniscus which extends beyond the field of view
In addition, a fourth grade representing meniscal tears occurring
within the body of the ligament that cannot be seen
arthroscopically can be included (Schramme et al., 2006).
Arthroscopic debridement is the treatment of choice. Grade I tears are left
untreated, while grade II and grade III tears are debrided as effectively as
possible. Postoperatively horses are maintained on controlled exercise for up
to 6 months. The prognosis for return to exercise in grade I injuries is 63%,
56% for grade II, and 6% for grade III (Walmsley 2005). More recently,
concurrent biological therapies (such as intra-articular or intra-lesional
mesenchymal stem cells) have also been used based on evidence of
meniscal regeneration in experimental animal models (Murphy et al. 2003). In
a limited number of reported cases, this appears to have improved the
outcome (Ferris et al. 2014) although the use of MSCs is only recommended
in those cases with a stable stifle joint and without meniscal displacement.
The ‘terrible triad’ – cranial cruciate, medial meniscus and medial
collateral ligament
This concept of a ‘triad of injuries’ is derived from human and small animal
clinical practice but is actually rare in horses except with severe impact
trauma to the stifle. Meniscal tears are most frequently seen in isolation with
a much lower frequency of injury affecting the cranial cruciate and medial
collateral ligaments.
VIII Patellar ligament injuries
In order to identify the patellar ligaments ultrasonographically, the transducer
is positioned transversely and moved distoproximally from the tibial crest to
the patella. Over-strain injury to these ligaments is rare. The only straininjuries are seen in the middle patellar ligament. Lateral and medial patellar
ligament injuries may be associated with wounds or previous desmotomy
procedures. Clinical signs include swelling surrounding the ligament with pain
on palpation with the stifle semi-flexed. Results of diagnostic analgesia of the
stifle is variable and are frequently negative.
Treatment is conservative.
There are limited clinical data available on outcome but the prognosis is
considered to be guarded.
IX Collateral ligament injuries
These injuries are rare. Severe injury results in a widening of the joint space
on the side of the injury. Enlargement of the ligament is the most obvious sign
recognized during ultrasonographic examination. In some cases, avulsion
fractures of the insertion sites of the ligament can occur. If the damage to the
ligament produces significant joint instability, the prognosis is poor.
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February
2016
East
London
Convention
Centre,
East
London,
South
Africa
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