New Developments Using the Four Point Concept
2001 - 14th Annual Bluegrass Laminitis Symposium Notes
New Developments Using the Four Point Concept
Written and presented January 2001 by R.F. (Ric) Redden, DVM
The strength of the four point trim concept continues to grow as I find new ways to apply the magic “pivot point” to the foot. This concept has the ability to transfer load and effect the tension in the suspensory/tendons of the equine digit, which appears to be directly related to the reperfusion of compromised growth centers. Reperfusing these vital growth centers greatly enhances the genetically programmed healing response of the foot.
Many people ask, “How does this method differ from traditional shoeing?” and “How do other versions of the four-point method differ?” The answers to these questions are as varied as the number of farriers using the four-point trim, but the basic formula remains the same.
Traditional shoeing is basically designed to protect the foot while offering little or no mechanical aid to enhance perfusion of the sole corium and laminae. It also fails to attenuate the tension of the deep digital flexor (DDF) tendon as it courses over the navicular bone.
Today’s definition of traditional shoeing can be traced back a couple of hundred years at best. Do you ever wonder, “What was considered ‘traditional’ before this?” Shoes worn by horses throughout Europe and Scandinavian countries hundreds of years ago are displayed at teaching institutions and museums, while thousands of others are in storage. Most differ greatly from the traditional shoe of today or even of the shoes that made their way into the first few books written on the subject.
I challenge those individuals who decry the four-point concept as not being “traditional”. This concept is actually so old that it is now new again. Hundreds of years ago, horses wore shoes designed to enhance the blood flow to the foot; and therefore, aid natural healing. These shoes were used well before present day shoeing standards were altered by more recent writings. It would be interesting to know when and how the farriers of Columbus’ era discovered the strong influence of placing the breakover well behind the apex of PIII. Obviously there were no x-ray machines at that time, so the only way to discover the location of the bone in relation to the shoe would have been to cut the foot and shoe down the sagital plane. I am certain that some who were inspired to move forward did just that.
How does the four-point concept work to enhance the healing environment of the foot? Apparently a very delicate equilibrium exists between the flexor tendons and suspensory structures of the foot. When in harmony, these groups act as a unit with a multi-complex function.
The laminae, especially the anterior two-thirds, are a direct antagonist of the DDF tendon. The extensor tendon that attaches to the most proximal prominence of PIII is also an antagonist of the DDF, but it is considered the weaker of the two. Furthermore, the coffin bone is supported within the capsule by the laminae, chondral collateral ligaments, impar ligament, the sole corium, sensitive frog and digital cushion.
The laminae along the posterior half of the foot are also attached to the flexible ungual cartilage. Apparently, this cartilage is a very forgiving structure that significantly prevents laminae sheering in most laminitis cases. The entire system rests in the sling of the DDF that is multi-functional itself.
For the sake of discussion, lets simplify the biomechanics of the digit and develop a meaningful and useful alertness for the load sensors and their caution lights. Lets assume a large majority of the horse’s weight is resting in the sling of the DDF. This weight extends through the tendon, down the cannon bone and across the proximal sesamoids. It makes a turn and continues down the back of the pastern, followed by another abrupt turn under the navicular bone where it attaches to the base or semi-lunar surface of the coffin bone. Remember that the bone is rigid. It is attached to the laminae and a very flexible, highly sensitive blood barrier, which are both attached to the semi-rigid hoof capsule.
As down load is placed upon the limb, each structure comes into play. If we see the tendon as if it were a large “rubber band” attached to a highly sensitive coil (the muscle) programmed for delicate suspension, we can imagine the weight of the horse passing through the fetlock and lower digits causing them to reach maximum flexion.
If the suspensory is cut while the limb is in full flexion, the fetlo