Page 706 - Adams and Stashak's Lameness in Horses, 7th Edition

672 Chapter 5

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A B

Figure 5.72. Laser arthrodesis of the tarsi is usually performed TMT joint (A), and the position is confirmed by fluoroscopy
under fluoroscopic guidance with the horses in dorsal recumbency. (C‐arm) or radiographs (B).
The laser fiber is inserted through needles placed into each DIT and

A follow‐up study using ethyl alcohol in horses with returned to full athletic function. The authors’ conclu-
DT OA revealed a rapid reduction in lameness, such that sion was that the convalescence was shorter than fol-
horses could return to their intended use after injec- lowing surgical arthrodesis, but that the surgery time
tion. Contrast arthrograms were performed in these was prolonged due to the sizable incisions that must be
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horses and when no communication with the PIT or TC closed. However, with all the options present for arthro-
joint could be identified, 3 mL of 70% ethyl alcohol desis and facilitated ankyloses, neurectomy of the tibial
(prepared from 95% laboratory‐grade ethyl alcohol) and deep peroneal nerves should be considered a salvage
was injected via the needles used for the arthrographic procedure and not a first‐line approach to horses with
evaluation. Lameness resolved in 18 of the 21 treated nonresponsive OA of the DT joints.
horses, but the horses did not develop the degree of joint
fusion expected based on the original study in young,
healthy horses. However, the horses with clinical OA Tarsocrural Joint Effusion/Bog Spavin
had a rapid and sustained reduction in lameness such Synovitis and fluid accumulation within the TC joint
that they could be trained (i.e. brought into work) or is a common finding in young horses and is referred to
competed within days following treatment. by laypeople as “bog” spavin. Most often it is a benign
nonseptic fluid of unknown cause. When distended, the
TC joint protrudes into four distinct pouches. The larg-
CUNEAN TENECTOMY est and most prominent is located dorsomedially, with a
The proposed rationale for performing cunean tenec- smaller one dorsolaterally and two large plantar (plan-
tomy is to reduce the torsional forces on the cuboidal taromedial and plantarolateral) pouches on each side of
bones of the tarsus, which presumably result from ten- the joint just dorsal to the tuber calcaneus. Pressure
sion in the medial extension (cunean tendon) of the cra- exerted on any one of these swellings can move the fluid
nial tibial muscle. 46,55 The procedure is simple to perform between the joint pockets. These fluctuant, movable
in the standing horse. Clinical reports on the success swellings must be differentiated from periarticular
rates for cunean tenectomy are lacking, but anecdotal edema (local or diffuse) with less distinct fluid pockets
information indicates efficacy in many horses. It seems that is more characteristic of an extra‐articular joint
that the clearest indication for cunean tenectomy would problem.
be in horses with chronic lameness that has failed to Injury to the TC joint can occur due to stops, quick
respond to medical treatments and is alleviated by local turns, or other traumatic events that can create injury of
anesthesia of the cunean bursa. However, infiltration of the joint capsule. Occasionally, performance horses can
the cunean bursa with local analgesia may not be spe- develop acute TC effusion manifesting as a severe lame-
cific because of the adjacent joint capsules. Efficacy of ness (approaching that of sepsis). Synovitis and capsuli-
cunean tenectomy may depend on early return to exer- tis are probably significant components of the pain
cise before scar tissue replacement becomes restrictive. creating lameness, but the cause can be elusive. In these
Currently, cunean tenectomy is performed infrequently cases, radiographic abnormalities are usually absent.
because it is unlikely to completely restore soundness. Horses are treated with rest and local and systemic anti‐
inflammatory therapy. Response to therapy can be pro-
Neurectomy of the Tibial and Deep Peroneal Nerves found and rapid. However, structural damage such as
CL sprain or nondisplaced fracture should be ruled out
Neurectomy of the deep fibular nerve or a partial before using anti‐inflammatories and returning the
neurectomy of the tibial nerves has been reported as a horse to work. As is often noted in horses with osteo-
treatment for horses with bone spavin. The technique chondritis dissecans (OCD), the swelling is often not
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has reported that approximately 60% of treated horses painful to palpation.