(Gough et al. 2010). However, it was considered difficult to separate the effect
of tiludronate from the effect of the controlled exercise regime in improving
lameness. Clodronate, a new bis-phosphonate has become available for
treatment of bone-related lameness, but has not been validated for the
treatment of distal tarsal osteoarthritis to date. My guess is that, clodronate
will become the more popular drug as it is easier to give and cheaper. This
combination means that it will probably be used more in the long run, even
though there are no scientific data supporting its use. All we have are some
studies sponsored by the drug companies selling the product, in order to
obtain FDA approval. Based on those studies, I remain unimpressed by the
scientific merit and clinical efficacy, but very impressed by the marketing.
Calcium dobesilate
Calcium dobesilate has an effect on pressure dynamics in the subchondral
bone of osteoarthritic joints of rabbits and could potentially be used as a
treatment for the early stages of osteoarthritis in horses. Similar to OA, early
stages of navicular disease in horses have been observed to be associated
with increased hydrostatic pressure due to venous congestion in the
spongiosa adjacent to joint surfaces. This can be observed as increased
signal intensity in fat suppressed images in the spongiosa of the navicular
bone. In a recent paper 12 horses diagnosed with chronic foot pain and
demonstrating increased signal intensity in fat suppressed images in the
spongiosa of the navicular bone (Janssen et al. 2011). Ten horses (83 %)
lameness improved by 2 months and 8 horses (75%) were sound at 4 months
after treatment. There was a general trend for reduction in the severity of MRI
abnormalities during the study period. The authors suggested that calcium
dobesilate was a potential treatment option for horses with foot pain
associated with increased signal intensity in fat suppressed images in the
spongiosa of the navicular bone. Calcium dobesilate has also been used for
the medical treatment of subchondral cyst-like lesions in joints of horses
(Jackson et al. 2006).
Neutraceuticals
Perceived as harmless in the long term, nutraceuticals, attract a growing
int erest from horse owners for the management of equine osteoarthritis. Yet
the evidence of their effectiveness is scarce. Among the major nutraceuticals
on the market, glucosamine claims local and systemic anti-inflammatory
effects in vivo in horses, and claims to promote the synthesis of aggrecan and
reduce degradation of cartilage matrix; the unsaponifiable extracts of avocado
and soybean claim to decrease the loss of articular cartilage, while the effects
of chondroitin remain controversial. In the absence of irrefutable evidence of
their benefits, the only good news about the neutraceuticals remains the lack
of reported adverse effects.
Conclusion
Rapid resolution of lameness is a principal concern of many owners and
trainers and the reason why many horses are presented for veterinary care
with considerable pressure and expectation of ‘immediate success’. Intraarticular injections remain a common and important means of addressing
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
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