The following case study is a pony that I started trimming in February 2011. He had been bought back by his old owner in August 2010 when she became aware that his health was poor. His condition seemed ok when he came off the box and for the first week. They noticed some thick black tar on his front hoofs which when stripped away showed problems with his feet (guessed the sellers were trying to hide the issue). Initially he was put out to grass as he had always lived out in the summer, so they continued with the usual routine. About 2 weeks later he started to be lame and within another few days was showing laminitic signs in stance etc. He was brought in and a vet was called in, he was given a thick bed, bute and wet hay only. At this point it was thought that it was just a mild attack of laminitis, but after x-rays the prognosis was worse than anticipated. His pedal bones had dropped more than 15mm in each foot and both feet showed rotation (amount of rotation not given by vet). The vet said that clearly he had been poorly for some time and may have been on strong drugs when he came home. He was put on two bute per day plus ACPs and complete box rest for two months. The advice of vet and farrier was to put him to sleep.
Left fore x-ray 11.8.10.
In this image I have highlighted the pastern angle with a yellow line. Notice how the dorsal aspect of P3 is parallel to the yellow line – there is no P3 rotation present.
The red lines highlight the angle of the dorsal wall of the hoof and the dorsal aspect of P3 – there is approximately 15 degrees of capsular rotation.
So the bones are correctly aligned, P3 is exactly where it should be in relation to the rest of the skeleton. It is the hoof capsule that having lost its attachment to P3 has rotated out of position.
This is the same x ray. Here the blue lines highlight distal descent. The upper line marks the hairline (that is the purpose of the nail glued to the hoof wall), the lower line marks the top of the extensor process of P3. In a healthy hoof the 2 will be level, or close to level. This pony had more than 15mm of distal descent (commonly termed sinking).
The red lines are showing the palmar angle which is 16 degrees. In a healthy hoof this angle will be somewhere between 3 to 8 degrees.
The yellow line shows the sole thickness. I have had to estimate the position of the tip of P3 as it is hidden by the quarter clips of the shoe. The sole is very thin. P3 penetration of the sole is a danger in both feet.
Right fore x-ray 11.8.10
In this foot there is a tiny amount of P3 rotation – the dorsal aspect of P3 is not quite parallel with the pastern angle (yellow line).
Again there is great deal of capsular rotation – approximately 23 degrees.
Again the blue lines highlight the distal descent of P3. Note the difference in the joint spaces of the pastern joint, and coffin joint. The latter is enlarged – another sign of distal descent.
The red lines show palmar angle which is 18 degrees.
The yellow line highlights sole thickness.
At the beginning of October the x-rays were forwarded to the laminitis society, Liverpool University and a 2nd vet – again they were directed to have him put to sleep as there was too much damage. He was still on box rest, 2 bute per day and ACPs. His pain was increasing, he was sweating with pain and spending a lot of time lying down. In December 2010 bute was increased to 4 per day, which was felt too much for him long term, but until a decision about his future was made this dosage had to be given to help him cope.
In January 2011 His owner was persuaded to try imprint shoes (left). She was told he would be sound enough to begin leading out after a few days of their application. However they increased his pain. His vet felt the pain was resulting from the sensitive solar corium being pinched between the descended pedal bone and frog plate of the shoe.
A 3rd vet was brought in after their riding teacher suggested that he might be insulin resistant and that someone she knew had had success by testing and treating this. Blood tests showed that his insulin was off the scale. He was changed to a low sugar diet of Speedi beet and soaked hay. He was maintained on 4 bute per day for a further 4 wks with ACPs and started 14 tablets per day of Metformin. On 2.2.11 we removed the imprint shoes and fitted him with easycare Rx boots and pads.
So how should a laminitic hoof be trimmed? Below: The yellow line is the hoof capsule we need to grow. Currently the heels are too long, and are increasing the palmar angle, in other words tipping P3 up, causing its tip to press painfully into the sole. The shoe is attached to the rotated hoof capsule. As a result P3 is insufficiently supported, has no support from directly underneath (peripheral loading), and is free to drop out through the dangerously thin sole
Our goals are to:
1. Shorten the heels.
2. Grow a hoof wall that is attached to P3.
3. Grow a large amount of sole that is currently missing under the tip of P3.
4. Raise the pedal bone into a higher position within the hoof capsule.
Left: The pink lines are the trim we actually do.
The heels are shortened to correct the angle of the pedal bone in relation to the ground (palmar angle), Lowering the palmar angle reduces the pressure that the tip of the pedal bone is putting on the sole and allows the sole to grow and thicken.
The toe is bevelled to put break over where it should be in relation to the pedal bone, and to reduce pressure on the lamina of the toe wall, allowing the wall to grow with connection to the bone.
The shoe is removed to give more support directly under P3 (central loading).
Below is the first trim on 2/2/11. I removed the imprint shoes, shortened the heels and did nothing else. He was in a lot of pain despite the amount of pain killers he was receiving and I had to work in small amounts, allowing him plenty of rests.
Left: Notice how the sinking of P3 has caused the sole to bulge at the apex of the frog. There is no depth to the collateral groves at the apex of the frog. After 6 months of conventional treatment the sole is still as thin in this area as it was when the august x-rays were taken.
He was fitted with Easycare Rx boots which have softer soles than hoof boots designed for riding. The boots support and protect making the horse comfortable enough to reduce pain killers and increase movement.
Within a couple of weeks of the diet change and shoe removal the digital pulses started to get lighter and he seemed to be coping with the pain better. They reduced the bute slowly over the next few weeks eventually down to 2 per day.
I want to emphasise that the really important change was his diet. With a history of laminitis it was not surprising that he was insulin resistant (also known as equine metabolic syndrome). To control insulin resistance as much sugar as possible must be removed from the diet. As his hay had not been tested for sugar and starch content, and could be high, it was important to soak it to leach out as much sugar as possible.
Laminitis cannot be cured without this step! If your horse has laminitis get it off grass, soak hay for several hours, and feed only unmolassed sugar beet and balanced minerals. No farrier or trimmer can cure laminitis with any shoe or trim if the diet is not addressed by the owner!
The drug metformin is given to human diabetics. It seems to have fairly poor results with horses and although clinical trials have been disappointing, it is commonly prescribed. It is important to implement the low sugar diet even if metformin is prescribed. Dietary control is the key to controlling insulin resistance and preventing further laminitis. Visit www.ecirhorse.com to learn more about insulin resistance.
I suggested he be kept in a small area, big enough for him to move around should he want to. Box rest delays healing. When a horse stands still circulation in the feet is poor. Blood brings oxygen and nutrients for growth and healing, and carries away carbon dioxide and toxins. His vet was still advising box rest, and at this point there was no other grass free place to put him.
Further x-rays were taken on 25/3/11.
Above left is the x ray of his left fore taken on the 25/3/11. A poor quality film, we cannot ascertain the degree of distal descent, or the relationship between the dorsal hoof wall and pedal bone as areas of hoof horn and soft tissue are not visible. The 8/11/10 x-ray is on the right for comparison. The palmar angle has reduced from 16 to 6 degrees, and there is a huge increase in sole thickness. This accounts for his improved comfort.
Above left: Right fore x-ray 25/3/11. Note that in this x-ray both palmar processes are visible, the x-ray machine was positioned a little high or low, so it isn't a true lateral image. I am estimating that the palmar angle has reduced from 18 to 13 degrees.
By this stage he was much more comfortable, sound in his padded boots. He was still stabled, but being walked out inhand.
Below: the tip of the frog is recessed into thickening sole. Compare that to the situation at shoe removal (right).
Below left: The new growth just below the coronary band is aligned with the pastern – after 6 months of continual hoof wall separation and capsular rotation he is finally growing hoof wall that is attached to the pedal bone. Now we just have to continue this attached growth down to the ground. It is not necessary to remove hoof wall in front of the pink line. Provided breakover is positioned where it would be if the hoof was normal (ie. nothing touches the ground in front of where the pink line meets the ground) movement biomechanics will be correct. Removing the excess hoof wall only weakens the hoof capsule. Below right:The stretched lamina are visible at the toe.
At the end of April 2011 he was moved to a yard where he could have access to a stable and a yard area, allowing him the freedom to move around as he wanted. This improves circulation, growth and healing. The vet requested that he was slowly brought off the bute to see if he could manage, this was done from May and he was totally off bute by the end June and was fine. My belief is that he could have come off the bute sooner if he had not been box rested.
5 ½ months from shoe removal and possible euthanasia – he is sound and has grown a nearly normal hoof. There is still damaged lamina growing out at the toe, and he is still building sole under the tip of P3.
In the 16.8.11 photos note the growth rings half way down the hoof. The upper inch of newest growth (yellow arrow) is fairly smooth with no obvious rings. This indicates that his insulin resistance is under control by strict dietary management. Insulin resistance cannot be cured, only controlled. Great care will have to be taken over allowing him access to grass for the rest of his life. He will always be at high risk of getting laminitis again.
Above left 16.8.11: In this view note how the frog sits within a bowl of concavity. Compare this to the photo taken the day his shoes were removed. He now has good sole thickness under the perimeter of P3. In front of this there is still an area of lamella wedge present (yellow arrow). His hoof wall is still a little stretched away from P3.
He is now sound and healthy. He has a realzest for life and has taken on the job of teaching a new child to ride.