11 / 24
EQUINE MATTERS
10
SUMMER 2016 ISSUE
HEALTHY TENDONS
Several studies have found that there is a
window of opportunity in the adaptation of
tendons to exercise. When foals were
allowed constant pasture turn out rather than
box rest or box rest with enforced exercise the
tendons of the constant pasture group were of
a better quality compared with the other two
groups. This will ensure that the flexor tendons
are most resistant to injury during adulthood.
Therefore the gambolling activities of foals
at pasture seem to be ideally suited and
essential to condition the tendons at an early
age
(figure 2)
!
Once a tendon suffers an injury, be it a full
blown tendon injury
(figure 3)
, or continuous
microdamage to the individual tendon fibres,
the repair leads to the replacement of the
normal tendon collagen with scar tissue. Scar
tissue forms from a different type of collagen
and results in a tendon that is structurally
stiffer than the original. This will make it
more vulnerable to repeat injury. Prevention
of tendon injury is therefore key and four
broad approaches for prevention can
be considered.
Prevention
1. Maximise the quality of the tendon
prior to skeletal maturity. Using carefully
tailored exercise regimes during growth
will potentially improve the quality of
the tendon and minimise effects of
degeneration induced by racing and
training after skeletal maturity.
2. Reducing degeneration after skeletal maturity
may be the answer to the prevention of
tendon injuries, and new studies are looking
into what causes this degeneration and how
it can be avoided. However, currently we
know that high repetitive loading (fast
speeds/high jumping) is likely to be the
most damaging
(figure 4)
.
3. Reduce the risk factors for tendinitis.
Clinical tendinitis is provoked by sudden
peak forces that overcome the strength of
the (degenerated) tendon. This can occur
at any time, including at pasture, but is
obviously most likely when the tendons are
loaded maximally - at high speeds and/or
over high jumps. This explains why the
best horses are more prone to injury.
Ground surface, which affects the horse’s
speed; fatigue, e.g. after a long race or
in unfit horses; jumping; shoeing and
increased weight are all examples of
factors that can increase the peak tendon
loading and are therefore risk factors.
Making sure feet are well trimmed, and
adapting the fitness levels of the horse to
correlate with the desired level of exercise
are both essential. A good warming up/
cooling down regimen is also recommended.
4. Early detection. This is not really a
prevention strategy as a degree of injury
has already occurred. However, if a
tendon injury can be detected early, it is
possible to prevent progression to more
severe disease. This relies on palpating the
tendons carefully before and after exercise
to detect any heat, swelling or pain. If
there is any doubt, your veterinary surgeon
should be contacted to perform an
ultrasound scan of the tendons.
Figure 2. Fooling around in the pasture
can help to condition the tendons in
preparation for adulthood
Figure 3. Marked swelling down the
back of the cannon bone signifies
severe tendon damage
Figure 4. The wavy appearance of the
superficial flexor tendon is consistent with
complete rupture. This injury occurred on
landing during a showjumping class
Prevention is better
than the cure,
particularly with
tendon injuries,
but early detection
is equally important
to prevent a more
serious injury with
catastrophic
consequences!