Zoe: Complicated Laminitis in a Horse

By 
​David A. Rustebakke, DVM
Dr. Rustebakke is a long time large animal veterinarian, and owner of Rustebakke Veterinary Service

If Zoe looks a bit sore in the above video, she has a good reason.  Four months ago she was on the verge of being euthanized from complicated laminitis.  She was in severe pain and could barely walk.

This is a story about a special horse and a dedicated horse owner.  We first met Zoe in October of 2017.  Her owner Mark Thorne had called me to evaluate her and see if there was any chance she could be saved.  She had foundered last summer, was in extreme pain, and her coffin bones had penetrated through the soles of her front feet.  She spent the majority of her time lying down.  I explained that the prognosis was grave; horses rarely survive sole penetration by the coffin bone.  Mark already knew that.  He persuaded me to drive to Harvard, Idaho and at least take a look at her.

The first chance that I got, I took a drive to Harvard.  I found  Zoe lying in a scrupulously clean stall deeply bedded in fresh shavings.  She was lying on her side to keep the weight off her painful feet; she was in good physical condition, and had no sign of bed sores.  Her feet were bandaged to keep them clean.  We removed the bandages to inspect the bottom of the feet; sure enough there were tracts in both feet that led to the tip of the coffin bones. 

We persuaded her to get up; she was so sore we had to anesthetize her front feet to get her to stand.  Radiographs (see below) confirmed that the coffin bones were rotated about 20 degrees away from the hoof wall, and the coffin bones were coming through the bottom of the feet.   Zoe had been shod with a reversed horseshoe with a lift at the back which elevated her heel and reduced the pull of her flexor tendons.  The coffin bones did not appear to be sinking, so we assumed that the laminar attachments at the heel were still intact.  But we somehow had to de rotate the coffin bone and establish a normal coffin bone angle while not increasing the pull of the tendons trying to pull the coffin bone off the anterior hoof wall.

What convinced us to try was Mark's determination to save her.  He was spending countless hours taking care of her, keeping her feet bandaged, keeping her clean, and keeping her as comfortable as possible.  Often what makes or breaks a difficult case is the aftercare.  I could see she would be in good hands by a dedicated and determined owner.

After again explaining  the poor prognosis, Mark asked us when we could start treatment.  I explained that we would need to put together a team in order to maximize our chances of saving her; we needed a veterinarian, a  veterinary technician, a competent farrier, a cooperative horse, and a dedicated owner to have any chance for success.  We had 4 out of 5; myself, my technician Sandra Whittaker,  Zoe who had  proven to be a willing participant, and Mark the owner.  We needed a farrier.

I called several  farriers that I had worked with over the years.  Paul Magan, a Certified Journeyman farrier  from Moscow lived  reasonably close and had the experience and training to help us.  I had worked with him before on other cases and knew that his skill, knowledge, and work ethic would be invaluable.  His positive, "can do" attitude was a huge asset as the treatment progressed.   

On a cold winter day, December 6, 2017, we met Paul Magan and Mark at the stable near Harvard.  Together we came up with a plan.  I would use sedation and local anesthesia to make Zoe comfortable enough to enable us to work on her.  We would use x-rays to guide how we trimmed her feet and Paul would build a shoe to give her maximum support.  Part of the treatment was also surgical; I would transect the deep digital flexor tendons in both front legs.  If left intact, the pull of the  tendons would continue to rotate the coffin bones away from their normal position; a deep digital flexor tenotomy would allow us to reposition  the coffin bones to their normal position relative to the other bones of the lower leg.

These pictures show the trim; we lowered the heels to put the coffin bones back into normal position.  We also removed the anterior hoof wall and the dead laminar tissue overlying the coffin bone.  

Farrier Paul Magan initially applied what is called a heart bar egg bar shoe with a hospital plate.  The idea is to recruit the non painful areas of the foot to carry the load; the heart bar gives gentle support to the frog,  The rest of the space is filled with impression material, a soft rubbery material that gives support to the sole.  The shoe is drilled and tapped so we can bolt on a removable aluminum plate that allows us to keep an eye on the sole, while holding the impression material in place, and keeping out foreign material.  I don't have a picture of the original shoe; the shoe shown here was a reset done on March 3 with an open toe egg bar shoe with a hospital plate.  This final shoe was placed to relieve  pressure on the toe while giving good support to the heels and underside of the hoof.

After the shoe was in place we did the tendon transection.  The surgical site was blocked with local anesthetic and prepared for aseptic surgery.  A small incision was made over the tendon, it was dissected free of the other tissue in the region and transected as seen in the video.  After the transection the skin and subcutaneous tissue was sutured and and we applied a heavy support bandage.  The surgery was repeated on the other leg.

The pictures show what the foot looked like after the initial treatment.  The anterior hoof wall was removed and treated with a disinfectant, and the leg bandaged to give support to the surgical site.  The egg bar heart bar shoe is in place with the attached hospital plate.

On January 4 the shoes were reset, and more of the anterior hoof wall was removed to put the coffin bone in a more normal alignment.  At that time she was walking better, but still sore.   On March 3 Paul Magan applied an open toe heart bar to completely relieve the pressure on the front of the hoof; like before it was packed with impression material and had a hospital plate attached.  

The above radiographs show the position of the coffin bone on March 3, 2018.  The bone itself will not rotate back into normal position, but by removing the dead tissue under the hoof it may allow the new hoof growth to grow down into nearly normal position. 
Zoe is not completely sound and may never be completely sound, although it is too early to be able to say what the eventual outcome will be.  However as you can she is happy and doing reasonably well.  She has been a wonderful cooperative patient, and her owner has been a pleasure to work with.  This would not have been possible without a team approach.  A special thanks to Zoe's owner Mark Thorne, farrier Paul Magan of Moscow, and my veterinary technician Sandra Whittaker.  Zoe's gentle nature and perseverance through this entire episode has been an inspiration to all of us involved with her!