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New Hoof Repair and Reconstruction Techniques

Category: Articles by Farriers > Andrew Poynton FWCF

Added 11th November 2009
  (1) Hoof Repair Tools and Materials
   
 
(1) Hoof Repair Tools and Materials
   
  (2) The revealed cavity
   
 
(2) The revealed cavity
   
  (3) The diseased area partially excavated - 1
   
 
(3) The diseased area partially excavated - 1
   
  (4) The diseased area partially excavated - 2
   
 
(4) The diseased area partially excavated - 2
   
  (5) Sole view
   
 
(5) Sole view
   
  (6) Prepared foot
   
 
(6) Prepared foot
   
  (7) Sole view with plastic skin around wall
   
 
(7) Sole view with plastic skin around wall
   
  (8) Defect filled, still hardening
   
 
(8) Defect filled, still hardening
   
  (9) Isolated area excavated
   
 
(9) Isolated area excavated
   
  (10) Shoe ready for reception, steel or plastic
   
 
(10) Shoe ready for reception, steel or plastic

By Andrew Poynton FWCF

Hoof Wall Cavity Debridement and Reconstruction

Advancing farriery techniques are developing in response to the need.  Many of today’s horse-owners wish to ride and keep in work all year round with little or no holiday such as the hunter or polo ponies had to rest and recoup for a few months.  The desire to do it ‘naturally’, ie live out, does not always help, particularly if the horse is a light thoroughbred living out in wet conditions!  So the farrier can either give up or devise new ways of meeting this incredibly demanding task of keeping the horse sound and on the road.

All is not lost.  As well as practising farriery to a high standard along with good stable management, we have new materials and techniques being introduced into the industry and making it possible to offer more for the horse and rider.  This is a rapidly growing area thanks to a progressive attitude amongst farriers.

In this article Andrew Poynton FWCF describes a hoof repair technique which restores the hoof capsule integrity to enable regained comfort and soundness for the equine.

Tools and Materials

Regular farriers’ tools (rasp, hoof cutters and knife) are used along with a motor high speed burr tool.  The materials for this work are:

  1. Surgical spirit is an antibacterial spirit used on the hoof after thorough debridement to leave a cleansed base to work from.
  2. The Imprint® Adhesive is a powerful adhesive developed and tested to withstand extreme conditions; this works even when moisture is present.
  3. Imprint® Granules are a blend of low melt thermoplastics formulated to closely assimilate hoof horn toughness (approximately 65D shore hardness).  It is notably a non-toxic and biodegradable substance which makes up more than 90% of the repair material.  It softens at approximately 65°c to become like chewing gum in consistency.  This is achieved by immersing it in boiling water (100°c); it becomes hard again at below 30°c, but retains some flexibility like horn and will not shatter.
  4. Personal protective equipment: latex gloves and safety glasses.

Priorities When Carrying Out Remedial Procedures

The technique must be learned and practised.  Effective results are to be expected.  Understand what caused the problem in the first place.  Patching over a problem will not work.  The detail in the work is its quality.  The skilled trimming and balance of the foot is paramount.  

Hoof Wall Cavity Treatment

Often when dealing with severe hoof defects the farrier will need to work closely with the veterinary surgeon; this may be initially to agree an effective course of action and treatment, and then possible sedation of the patient if it is either in pain or fractious.  We depend on each other.

The Procedure: Case Study

Hoof preparation requirements are summed up in accurate trimming, thorough debridement and antibacterial cleansing.

The example used here to illustrate this technique is a hoof wall cavity in the lateral toe quarter of the left fore foot.  The horse displayed 2/10 lameness and landed in advance on the lateral toe quarter.  The white line was not separated, only looked black and oxidised, but on investigation and paring away revealed hoof wall separation to more than half the depth of the hoof (image 2,3,4,5).  It appears that the main contributing factor here was the horse’s conformation predisposing this lateral toe to heavy landing.  Once recognised this can be accommodated, but the effect was that the lateral wall was being pulled away, and across the toe, flattening.  You will also notice the beginnings of a central toe crack where the flex and stress is concentrated.

To remedy this, the toe is trimmed and either side of the crack the wall rounded and thinned a little thereby taking out the flattening across the toe.  

Hoof Wall Cavity Repair

When trimming the hoof the medio-lateral foot fall needs particular attention.  If there is enough hoof to trim, then level foot fall may be achieved by this means alone, but failing that, as in this case, the lateral toe of the shoe can be  rasped and thinned as a sidebone shoe; if that is not enough, a medial lift added to the shoe or foot will achieve the required result.

Back to the defect, all undermined horn was removed.  The bacteria in this case appear to be quite specific only attacking the stratum internum (lamella layer). This is not always the case, sometimes it is only the stratum medium that is diseased, creating the effect of plywood without the glue; other times the whole lot is eaten away indiscriminately! Anything either black and putrid or white and mealy was cut away.  Most of the work was carried out using hoof nippers then a loop knife.  The final debridement was performed using a dremel with a 4mm round burr.

I find using a partly worn burr at a moderate speed when cutting close to vascular structures tends to rub the softer tissue but still cut the horn.  As you can see it was almost a bloodless procedure.  The spot of blood high in the toe was drawn at a deep soft area.  This makes this case study all the more interesting and informative as this is often what is encountered.

Once all trace of diseased tissue was removed, a number of bulb-shaped key indentations were cut around the margins of the defect; all edges were undercut so that when the area was filled it was mechanically held in place in addition to the adhesive bonding. The whole area was then cleansed using surgical spirit.  Being anti-bacterial, this was allowed to vaporise before applying any adhesive (image 6).

The spot that bled was covered with a small amount of Keratex Putty, an antibacterial wax, to isolate it; this was then to be excavated once the procedure was complete. The remaining area was covered with a thin layer of adhesive including the bordering sole. This makes provision for the repair to wrap under and onto the sole thereby sealing the vulnerable white line margin.

A quantity of Imprint® Granules sufficient to amply fill the deficit area was heated in a container by pouring on boiling water.  Latex gloves were worn at this stage.  The plastic became soft and translucent in a few seconds.  It was taken from the water and moulded into the defect ensuring that adhesive was present around all edges of the repair.  The adhesive and plastic was moulded under the hoof onto the sole (image 7) The foot was placed on the ground and the plastic allowed cooling and hardening naturally (image 8)  Provided the horse does not paw at the ground this works well, as no pressure or tension is created on the repair area.  If the horse is liable to scrape the ground then just cooling the lower part with freezer spray (additional material) solves that problem.  This particular case was having Imprint® shoes fitted following the repair, and had additional plastic applied as a skin on the hoof.  Once the plastic was hard and the adhesive set, at about ten minutes, the foot was ready for shoe application. A conventional steel nail-on shoe can be used along with this type of repair.  Even nailing into the repair area is fine; the plastic takes nailing and clenching well.

Before fitting the shoe a hole was cut using the burr to reveal the putty plug and allow access to the cut for medication and drying, open to the air (image 9, 10).

Each time the foot is trimmed and shod, any areas where it appears to be undermined in any way should be cut back until a perfect union is found and the procedure repeated, otherwise treat as horn.  The material is easy to use, enabling large or small hoof repairs efficiently, safely and economically. I find it a valuable material and serious aid for speeding recovery for many horses’ feet.

Safety Warning Do not burn a hot shoe onto the plastic, it is likely to catch fire and drip hot molten plastic on your hands.  It will stick and could cause severe burns. 

© Copyright Andrew Poynton FWCF