Q: My horse has been diagnosed with spavin. The spavin is very active but he has had cortisone injected intothe tarsal bones and responded well. I want the spavin to fuse quickly and have been advised to work him hard on bute.
Can I do the usual schooling exercises, such as lungeing and circles, as long as he is sound or should I stick to riding straight lines? Also, is there a time span on the fusing or are all cases different?
Jo Holmes MRCVS replies Spavin describes arthritis in the small hock joints, usually in the Distal Intertarsal (DIT) and Tarso Metatarsal (TMT) joints.
These joints are ‘low motion’, making little contribution to flexion and extension, which is possibly why they are more susceptible to concussion.
Arthritis leads to joint fusion – cartilage is worn away and new bone grows across the joints to stabilise them.
This reduces the pain caused by instability. The process can take up to two years to complete; in the meantime, the horse shows varying degrees of lameness which often improves with exercise.
The affected leg maymove inwards, across the midline of the horse’s undercarriage.
Lack of hock flexion will cause the toe and the outside of the shoe to wear and the horse will respond positively to a flexion test.
Treating your horse medically is usually the easiest and cheapest way. Surgery can take two guises: joints are drilled across to promote rapid new bone growth or a chemical irritant is used to corrode cartilage to induce the same effect.
Surgery can achieve joint fusion in a matter of months, but having a general anaesthetic always carries a risk.
Intra-articular cortisone injections are most effective at reducing joint pain, but their effect tends to last only for six weeks and repeated injections are costly. Phenylbutazone (bute) can also relieve pain.
Work your horse normally, so long as he stays sound. If he is lame on a circle, keep to straight lines.
You may find a ‘spavin shoe’, made with a lateral extension to the outside heel, will help.
The lateral extension encourages the horse to place his weight further laterally, widening the hind limb stance back to normal and re-exerting force through the fusing joints.
Ask your farrier and check with your vet that such a shoe is appropriate.
Monitor your horse’s progress when he is off bute every so often – note how he feels when you ride him. Radiographic change to the joint can also assess the recovery speed.
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