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9
EQUINE MATTERS
HEALTHY TENDONS
Veterinary surgeon
Egbert Willems
XLEquine practice
Cliffe Veterinary
Group
Keeping tendons healthy
Egbert Willems DVM CertES(Orth) DipACVSMR MRCVS
Cliffe Veterinary Group, East Sussex
Strain induced injury of the tendons and ligaments is the most common
orthopaedic injury in athletic animals, be they equine or human.
Strain %
Stress
Tendon Stretching
Capability
partial injury
complete
rupture
returns to normal length
wavy
fibres
stretched
microtrauma
failure
1
2
3
4
5
6
7
8
A recent survey of race horse injuries
sustained at UK race tracks showed that
almost half (46%) of all limb injuries were due
to flexor tendon and/or suspensory ligament
injuries. This survey also confirmed that these
injuries were more common in older horses
racing over jumps than younger horses racing
on the flat.
Tendons and ligaments can be injured in two
ways: direct injury/laceration through the skin
or via overstrain, which we will consider
further. Overstrain can occur as the result of
sudden overload of the tendon, or via a
phase of degeneration culminating in tendon
injury. There may be many risk factors
involved in an injury:
●
speed of the horse:
the greater the speed,
the greater the risk;
●
age of the horse:
the older the horse, the
stiffer the tendon;
●
surface:
hard going is associated with
tendonitis, as it accommodates faster work
and increases peak impacts of the tendon;
●
height of the jumps;
●
weight the horse is carrying;
●
fatigue or fitness of the horse;
●
shoeing type.
Some of these factors may be adjusted, others
are inherent to the sporting careers of the
equine athlete and will not be easily altered.
The age of the horse plays an important role
in the ultimate strength of the tendon. The age
at which the equine flexor tendon matures is
estimated at around two years of age. Normal
young tendons have a crimp pattern to allow
for increased flexibility. The tendon loses some
of this crimp over time, with fibres at the core
of the tendon more affected. This increased
stiffness could lead to core lesions where the
central tendon fibres have torn once strained
(figure 1)
.
Figure 1. The black area within the
superficial digital flexor tendon is a
core lesion, with complete loss of
tendon fibres