several studies. The results seem to be somewhat dose-related, and reported
doses vary from 100 mg to 250 mg/joint. Contrast arthrograms must be
performed to confirm location of the needle and to rule out communication of
the TMT or DIT joint with the PIT/TC joint or the tarsal canal. If the arthrogram
reveals contrast in the PIT/TC joints or tarsal canal or failure to fill the
intended joint, the procedure is aborted. Leakage of MIA into the
subcutaneous space also produces noticeable inflammation that may lead to
a tissue slough. Pain in the immediate post-injection period can be profound
but varies among reports. Complications that have been observed include soft
tissue necrosis at the injection site, septic arthritis, unexplained increased
lameness, and delayed PIT/TC joint OA. This potential for serious
complications must be weighed against the appeal of the simplicity and
minimal cost of the procedure. We performed a study with 60 horses in which
bone spavin was treated with intra-articular injection of MIA. The procedure
was performed under general anaesthesia with the patient in dorsal
recumbency. Prior to injection of MIA, contrast arthrography was performed to
confirm intra-articular placement of the needles and to rule out undesirable
communications between the affected distal tarsal joints and the adjacent,
unaffected proximal intertarsal and tibiotarsal joints. A solution containing 100
mg MIA in 2 ml of 0.9% saline (sterilised using 0.22 ul filtration) was injected
aseptically into each of the affected joints. Postoperative walking exercise was
initiated within 24 h and patients were returned to full ridden work within 7
days. Owners were informed of the absolute necessity of 1 hour of ridden
exercise daily until fusion occurred. Long-term soundness was only obtained
in 22% of horses, although lameness improved in another 30% of patients
(Schramme et al. 2000). Marked post-injection pain was present in most
horses but subsided after 24 hours. These results were considerably less
favourable than those reported in an earlier study by Bohanon (1995) and a
later study by Dowling et al. (2004). In this latter study, horses were injected
twice the concentration of MIA under standing sedation (200 mg MIA per
joint).
Ethanol solubilizes lipids and induces nonspecific protein denaturation,
cellular dehydration, and precipitation of protoplasm. As such, it affects
chondrocytes in a similar manner as MIA. Ethanol has neurolytic properties
that could contribute to its reported early resolution of lameness. In normal
horses, no significant local post-injection reaction occurred and no persisting
lameness was induced. After 12 months, the TMT joints were largely
ankylosed and the horses were not lame (Shoemaker et al. 2006). Facilitated
ankylosis with ethyl alcohol in the tarsometatarsal joint has reportedly resulted
in significant improvement in lameness in 52% and deterioration in 19% of
horses. 75% of owners were pleased with treatment results (Carmalt et al.
2010; Lamas et al. 2011).
Laser energy (Nd : YAG or 980-nm gallium-aluminum-arsenide diode laser)
applied to the TMT and DIT joints has been reported to relieve distal tarsal
pain (Hague et al. 2000) Lameness improved in all horses in a series of 24
Standardbreds and Western performance horses. Stall confinement was
enforced for 2 days followed by progressive return to full activity over
approximately 2 weeks. The horses were reported to become sound before
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
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