Caudal heel pain, otherwise often referred to as navicular syndrome, is a common cause of lameness in the sport horse, particularly in quarter horses. With the progression of advanced imaging such as computed tomography (CT, “cat scan”), and MRI into mainstream veterinary medicine in recent years, our understanding of navicular syndrome has progressed far beyond the typical radiographic diagnosis of abnormalities within the navicular bone itself.
Injuries to the heel region that are classically part of the navicular syndrome include not only degeneration of the navicular bone itself, but also injuries to the numerous tendons and ligaments in the heel region, and injuries to the coffin bone in that area. Confirmation of pain coming from this region is typically made through nerve blocks during a lameness examination which are then followed by diagnostic imaging (radiographs, CT, MRI, etc).
If this pain becomes difficult to manage medically or through other surgical approaches (see bursoscopy, arthroscopy), one solution is removal of the nerves leading to this area, which causes a semi-permanent loss of sensation to the heel region. The body will naturally try to regenerate these nerves, however most horses will remain desensitized for a period of 2-4 years. This surgical treatment is typically performed under general anesthesia and can be performed bilaterally in a single anesthetic episode.
This is often a good solution for horses in low-level, nonstrenuous work to prolong their ability to be used while maintaining an acceptable level of comfort.
Neurectomy and Fasciotomy
Proximal suspensory desmitis, or inflammation of the origin of the suspensory ligament, is a well-recognized cause of lameness in athletic horses - and can be challenging to diagnose and resolve. The clinical presentation of these horses can vary from severe lameness of one hind limb to subtle changes in performance, way of moving or behavior.
Ideally, diagnosis is based on lameness examination with specific nerve blocks localizing the pain to the proximal suspensory region as well as diagnostic imaging (ultrasound, radiographs, nuclear scintigraphy, etc), confirming inflammation and pain arising from the upper 1/3 of the suspensory ligament.
Aside from medical therapies which may consist of rest and rehabilitation, shockwave therapy, laser therapy, or local injection of anti-inflammatory or regenerative therapies, there is a surgical option to treat this disease which has gained popularity and success over recent years. For hind limb injuries, this procedure consists of making a small incision, releasing a tight band of tissue which constricts the suspensory ligament and removing a portion of the deep branch of the lateral plantar nerve, which directly innervates the origin of the suspensory ligament. Often this procedure is undertaken in horses who have had repeated injury to the suspensory ligament, or in an effort to prolong the athletic career of a horse with a first-time injury. Results of scientific studies have shown improved rates of successfully returning horses to athletic use after this procedure compared to medical therapies. A similar procedure can be performed for horses suffering from proximal suspensory desmitis of the forelimb.