Hello,
Discussing
this question with Jan Glas
resulted in the following
comment:
Problems
with the stifle are not uncommon as it is one of the
biggest joints in the horse. So if a horse presents with
a stifle problem there could be many explanations like
congenital malformation, defective development , trauma,
infection , degenerative disease and vascular
disturbances (rare).
Locking
stifle or in veterinary surgery terms “upward fixation
of the patella” is seen in Friesian horses and
Shetlanders more often than most other
breeds.
First of
all you want to make sure the diagnosis is correct. For
example a loose piece of cartilage in osteochondritis
dissecans (OCD) can put a lock on a stifle as well ( so
you need an x-ray to sort this out) . Other causes
mimicking an upward fixation of the patella can be :
sprains of collateral ligaments, injury to cruciate
ligaments, injury to menisci and less frequent are
fractures.
Upward
fixation of the patella is influenced by some hereditary
factors , by the build of the stifle , how the muscular
development is and how the horse is standing on its
hooves
In acute
upward fixation of the patella, the hindquarter is
locked in extension as the horse attempts to pull the
limb forward. You will observe a typical situation :
fetlock, pastern and coffin are flexed while stifle and
hock joints are locked in extension. In late chronic or
repeated cases there can be signs of gonitis or
inflammation of the joint. Often the condition is seen
bilateral. Advancing the limb the horse will be seen to
drag his toe ending in excessive toewear on the front of
the hoof. In many cases it is not so obvious : a horse
can be
locked, standing in its box and can get loose
again by stepping outside.
So first
of all you need to be sure of the diagnosis for this
dictates
the type of treatment . In an acute
fixation you might want to back the horse, and push at
the same time the patella medially and downward. On the
other hand if it is a young
horse with lack of muscle development or a fast growing
horse in one of its periods of disbalance between bone,
joint and muscular development, then you might get away
with training on straight stretches with as less turning
as possible. Training by pulling a sledge can be
combined with straight work. Try to give the horse as
much movement as possible by turning out as much as
possible .
You
might check with your farrier: inside/ medial taking out of
the hooves , forcing the hoof to be lower on the inside
/ medial side
than on the outside/ lateral side and even making
hoofs as short as possible can be
beneficial.
Surgery
is an option, but only if all other treatment gives no
results.
In
Shetlanders with chronic upward fixation surgery in
terms of
“medial patellar desmotomy” is carried out. In
Friesian horses you might wait with surgery until severe
complaints. After surgery a broodmare can still be used
for breeding with the restriction that there is a
possibility of transmitting this problem to offspring. A
horse for the carriage might have less visible signs
after surgery than a horse in dressage.
Regards Jan Glas and Harry
Voesten
In
summary:
Be
certain of the diagnosis. Treatment: in immature young
horses as much turning out as possible , active training
to build muscles in long straight work, pulling sledge,
expert farrier correction taking out inside of hoofs and
shortening of hoofs. Surgery is a late
option.
News Bulletin (updated 5-23-08)
