Page 5 - Clinical Connections- Summer 2021

Equine

POOR PERFORMANCE

Andy Fiske-Jackson, Deputy Head of RVC Equine and Senior Lecturer in Equine Surgery

orses are frequently presented human eye, and those values return to the
to the RVC Equine Referral normal accepted range following nerve
H Hospital for investigation of poor or joint blocks, and the rider reports an
performance. Following acquisition of a improvement, this increases the security
thorough history, the horse is examined. of the diagnosis. OGA gives the user
Usually this will start with a lameness confidence to embark on a lameness work-
investigation. The equine industry has up in this situation and adds objectivity to
seen a surge in interest, availability, and the post-block assessment.
use of objective gait analysis (OGA) for the There has been debate about OGA
detection of lameness in horses and the focusing on the initial assessment –
RVC continues to be at the forefront of the whether the user should rely solely on it to
field with this technology. detect pain-induced lameness – certainly
The main advantage of using OGA we should not. However, once lameness
is the potential to remove bias from has been detected, and a lameness work
clinical decision-making. At the RVC we up using nerve and joint blocks has started,
are pursuing its use in measuring back improvements can be confirmed with
movement and seeking to correlate this Figure 2 OGA. Whilst nerve blocks may completely
with the presence of back pain. Inertial an owner reports a drop in performance resolve lameness when the area of
measurement units are placed on the horse and the values lie outside the thresholds, pain is desensitised, joint blocks can be
(Figure 1 and 2) and the horse is assessed it is sensible to explore the reason for the less conclusive. The response to stifle
both unridden (Figure 3) and under saddle. asymmetry to establish whether it is linked blocks in particular can be modest even
to the loss of performance; it certainly if demonstrable pathology is ultimately
Figure 1 demonstrates the limb which is producing evident on either diagnostic imaging or
less force than the others. arthroscopy. Improvement well below
Asymmetry can be so mild that it can be 50% can be expected in such cases and
difficult to detect. If this is the case, how OGA can add reassurance in confirming a
can we ensure it is clinically relevant? It subjective perception of improvement.
is obvious that its relevance should be Like all technology, its value is only as
assessed in the context of the horse’s good as its interpretation. Veterinarians
breed, use, age, history and what the rider are faced with this scenario every day
reports. As an example, a dressage rider (e.g. blood results, ultrasound scans,
Lameness ‘threshold values’ that exist may notice reduced hindlimb push off radiographs etc.) and, of course,
with OGA were derived by comparing during a canter pirouette in one direction experience is invaluable.
OGA measurements with veterinary expert compared to the other well before it
assessments following induced lameness. become visually evident when the horse
Whilst these thresholds should not be is trotted in hand. If OGA can detect a
interpreted as an absolute cut off point, if subtle lameness, undetectable to the With the support of the Animal Care
Trust, the Equine Referral Hospital has
recently acquired wireless ultrasound
probes. The probes emit a Wifi
signal that wirelessly connects with
any smartphone, tablet or Windows
operating system laptop, meaning they
can be used in remote areas without
internet connection. These probes are
light and easy to handle and the image
resolution is excellent. The absence of
wires makes them safer to use around
the limbs of horses and also allows the
screen to be placed in a safe location.
It also lends itself well to intraoperative
scanning facilitating maintenance of
sterility.

For equine referrals, please call: 01707
666297
Email:
Figure 3 equinehospital@rvc.ac.uk

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