Laminitis is a painful disease which causes the tissues within the hoof to become inflamed. The laminae, which are the sensitive tissues inside the hoof wall become weakened and stretched. During this process, the pedal bone (which sits inside the hoof) can start to separate from the hoof wall, causing it to rotate and sink. In very severe cases, the pedal bone can move so much that it can be seen coming out through the sole of the foot.

How do we know that the pedal bone has rotated?

Horses with laminitis often appear to have a stiff or pottery gait and may be reluctant to move. The lameness may be more apparent on hard ground and they may struggle to turn. The feet may also be warm to the touch with increased pulses at the back of the pastern. If your horse is showing signs of laminitis, your vet should be called out to perform an examination.

During the examination, your vet can take radiographs of the feet so that an assessment of the pedal bone can be made. Measurements can then be performed on the radiographs to assess the position of the pedal bone in relation to the other structures of the hoof.

Does the angle of rotation affect the prognosis?

Rotation of the pedal bone is one of the factors used to assess the severity of laminitis. Other factors include the weight of the horse and how many feet are affected. Measuring the angle of rotation of the pedal bone can help your vet and farrier to form a treatment plan. Although significant rotation has been associated with a poorer prognosis, there is evidence of horses with rotation of up to 30° being corrected. However, if there is significant rotation of the pedal bone and treatment is not instigated, the disease can progress. This can cause compression of the tissue under the pedal bone, leading to loss of bone, abscess formation and sinking of the bone.

How can the condition be treated? 

Once radiographs of the feet have been taken, your vet and farrier will work together to develop a treatment plan. At first, pain relief and exercise restriction is important in order to prevent further rotation of the pedal bone and to ensure that your horse is comfortable. Foot supports may also be provided. These are placed under the feet to protect the sole, reducing the risk of further pedal bone sinking and rotation.

Trimming the foot

Once your horse is comfortable and the condition is stable, trimming of the foot can be carried out. The amount and type of trimming required will be dependent on a number of factors. At first, only small alterations may be made every few weeks.

The aim of trimming is to stabilise the pedal bone. This is done by changing the way that the foot is placed and in which areas the foot is loaded. The foot should be trimmed regularly to prevent excessive growth in particular areas. Specialist shoes may be required to change the angle of the foot. This relieves pressure from different parts of the foot, while sole pads may also be used during this period. 

Alongside hoof care, diet is a very important factor in the management of laminitis, the horse should be kept at a healthy weight by controlling the diet and ensuring that the horse has regular exercise, as long as they are comfortable enough to do so.

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References:

Taylor, D., Sperandeo, A., Schumacher, J., Passler, T., Wooldridge, A., Bell, R., Cooner, A., Guidry, L., Matz-Creel, H., Ramey, I. and Ramey, P., 2014. Clinical Outcome of 14 Obese, Laminitic Horses Managed with the Same Rehabilitation Protocol. Journal of Equine Veterinary Science, 34(4), pp.556-564.