Page 47 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

22 CHAPTER 1

VetBooks.ir lame limb. These are mechanical events that must MANAGEMENT
obey Newtonian physics and, therefore, forces (F)
can only be changed by modifying the mass (M) or Arthroscopy, tenoscopy
the acceleration (A) of the body (F = MA, Newton’s and bursoscopy
Second Law of motion). The attempt to change the Endoscopic surgery (‘key-hole’ surgery) has revo-
mass of the body is most obviously seen in forelimb lutionised the treatment of joint diseases in the
lameness by the ‘head nod’, where the horse lifts the horse. Unlike open approaches, it allows direct
head before the landing of the lame limb. Changing visualisation of the majority of synovial structures
the acceleration of a limb by delaying the landing of in the horse, thereby providing diagnostic infor-
the foot on the ground leads to the ‘hip drop’ action mation about the cartilage, joint capsule, menisci,
seen in hindlimb lameness. Changing the impulse by tendons and certain ligaments. Additionally, it is a
increasing the contact time with the ground, in turn surgical tool and can be used, for example, to remove
leads to a ‘hip hike’. chip fractures from the intercarpal joint and osteo-
Objective kinetic and kinematic measurements chondral fragments from the tarsocrural joint and
from lame horses (using force plates and motion debride and lavage septic joints (Fig. 1.45). Due to
capture systems, respectively) have been the scien- its minimally invasive technique, only small ‘stab’
tific ‘gold standard’ for lameness detection and evalu- incisions are needed, thereby reducing trauma,
ation. Until recently, these methodologies were providing a better cosmetic effect and allowing
only available in large purpose-built facilities; how- an earlier return to function in the majority of
ever, portable systems using different combinations cases. Arthroscopy requires specialised, expensive
of horse-mounted accelerometers and gyroscopes instrumentation and a high skill factor from the
are becoming increasingly affordable and reliable. surgeon. It is not always possible to evaluate entire
Consequently, many clinicians are now using these joint surfaces (e.g. the DIP joint), so case selection
tools in everyday lameness workups. is important.
Although such systems do not replace the Tenoscopy and bursoscopy are developments
‘clinician’s eye’, they do provide objective assess- from arthroscopy, using the same techniques to
ments of lameness that are particularly useful when evaluate tendon sheaths, in particular the digital
evaluating responses to analgesia, or where repeated tendon sheath, the tarsal and carpal sheaths and the
evaluations after long periods of time are used in bursae, especially the navicular, calcaneal and inter-
assessing response to treatments. It is important tubercular (bicipital) bursae (Fig. 1.46).
to note that these systems do not measure forces The use of these techniques has allowed new con-
directly but relate them to the acceleration of dif- ditions to be diagnosed (e.g. desmitis of the intercar-
ferent parts of the body, then, by assuming sym- pal ligaments, cartilage lesions of the medial femoral
metry of movement between left and right sides condyle, longitudinal tears of the flexor tendons in
of the body, differences in motion of contralateral the digital sheath and meniscal and cruciate liga-
body segments and head are calculated. Hence, the ment injuries in the stifle joint). With further refine-
accuracy and reliability of such systems are depen- ments in techniques, procedures such as cartilage
dent on hardware (number of sensors and frequency resurfacing are now feasible.
of readings) but also on software algorithms that
interpret the raw data and produce on-screen visual Physiotherapy
aids for the clinician to read. Further explanation Physiotherapy forms an important part of rehabili-
of these systems is beyond the scope of this chapter, tation for lame horses. Qualified physiotherapists
but careful evaluation and constant improvement undergo extensive training and certification pro-
of such tools will certainly make them more widely grammes in some countries, such as the UK, and
disseminated in the equine veterinary field in the they work alongside veterinarians once an accurate
future. diagnosis has been made. There are a wide variety