Splints may be unsightly, but they don’t usually cause a horse too many problems. Vet Leona Bramall explains how they should be managed.
Splints are bony enlargements (exostoses) of the interosseous ligament that connects the splint bones to the cannon bone.
Inflammation and mineralisation of the ligament causes a surface bone reaction to the splint and cannon bones, resulting in the development of small to large bony lumps which can be felt around the splint bone region of the lower limb. Splints can occur throughout the year, but there is a higher incidence during the summer months.
For the most part, splints are cosmetic blemishes that don’t interfere with a horse’s long-term athletic ability.
However, some can result in significant lameness, especially in the immediate injury period or, in rare cases, where there is impingement of the suspensory ligament.
Each limb has two splint bones: the medial (second metacarpal bone, MC2); and the lateral (fourth metacarpal bone, MC4), which course on either side of the back of the cannon bone.
Splints generally affect the top third of the affected bone, but they are certainly not limited to this area and can occur in any part throughout the length of the bone.
The medial (inside) forelimb splint bone is most commonly affected, but splints may occur on the lateral (outside) forelimb splint bone, or indeed on either hindlimb splint bone, although this is less common.
Splints can occur as a result of trauma, foot imbalance, or secondary to poor knee conformation, namely bench knee. Young horses are more commonly affected, but splints can affect horses of any age.
Signs and diagnosis
Clinical signs vary in severity. Some horses show no evidence of pain or lameness, whereas others do appear lame, have soft tissue inflammation and pain on palpation.
If you notice that your horse has a splint, the recommendations are to put him on box rest until you have consulted your vet. If your vet examines your horse, they will do so at rest and will carefully palpate the splint to try to discover the likelihood of suspensory ligament impingement.
Your horse will then be trotted up to determine whether he is showing any signs of lameness. If he is lame, nerve blocks may be performed to confirm that the lameness originates from the splint and not from elsewhere.
A decision will then be made as to whether conservative management is likely to be sufficient, or whether further imaging is required.
Further imaging generally involves radiology (X-rays) with or without ultrasound assessment of the suspensory ligament.
In cases where suspensory ligament involvement seems unlikely, affected horses are generally placed on box rest and given oral anti-inflammatory therapy until the pain and inflammation subside and the lameness clears up. A controlled exercise programme can then begin. Remedial trimming and farriery may be recommended too.
In cases where the suspensory ligament is involved, prolonged box rest will be needed, with your vet evaluating your horse at regular intervals. In those cases that don’t respond to treatment, surgery may be required.
With time, splints will generally reduce in size, but the timeframe varies from weeks to months, and the new bone formation may never fully resolve.
Topical anti-inflammatories may be recommended by your vet to assist with soft tissue inflammation, but timely box rest and oral anti-inflammatories are the most important steps in the management of splints.
Your vet may also recommend hydrotherapy in the initial phase of injury. Distal limb compression, such as the use of a stable bandage and gamgee pad for up to 12 hours daily, may help to reduce the size of the splint.
In the past, other non-orthodox treatments have been used, such as firing and blistering, but these are no longer recommended and nor are they ethical.
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