Diagnosis, treatment, and farriery for horses with chronic heel pain

It has been estimated that approximately one third of all forelimb lameness in horses originates from the caudal third of the foot [1]. Lameness originating from the caudal third of the foot has generally been associated with pain arising from the navicular bone or its related structures; however, other structures in the foot can also cause lameness. Any one or combination of the following structures should be considered as a potential source of injury in horses that exhibit lameness localized to the posterior aspect of the foot. 1. Navicular bone itself 2. Navicular suspensory apparatus, which includes the sesamoid impar ligament (IL) distally and the collateral suspensory ligament (CSL) proximally 3. Synovial membrane of the navicular bursa (le, navicular bursitis or inflamed tissue [adhesions] between the navicular bursa and deep digital flexor tendon [DDFT]) 4. Distal aspect of the DDFT 5. Laminar tearing in the heel region 6. Solar bruising in the heel region 7. Some aspects of the distal phalanx (P3) 8. Synovial structures located in the distal interphalangeal (DIP) joint 9. Structural damage to the hoof capsule in the heel region, such as underrun heels or a collapsed foot The diagnosis of heel pain is not difficult when a horse's lameness resolves with a posterior digital nerve block; however, determining which of the structures located in the foot is the source of pain and establishing correct treatment is becoming increasingly more confusing. It seems that the more we learn about diagnostic anesthesia, the more clouded the picture becomes and that determining which structure within the hoof capsule is causing the pain is becoming more difficult. Horses with navicular/heel pain can be a diagnostic and therapeutic challenge to owner, clinician, and farrier. When advanced imaging techniques become available to all practitioners, the diagnostic dilemmas facing clinicians today may disappear. Until that happens, we have to rely on historical data (which is important and often overlooked), clinical findings, and routine diagnostics to localize the structure causing pain within the hoof capsule. Our approach to horses having lameness originating from the heel region is to try to determine which structure in the foot is causing the pain and then to develop a therapeutic plan. Severity and duration of the lameness, the horse's activity, potential owner compliance, and the experience of the owner's farrier should be considered. The horse's hoof wall quality, conformation, environment, and occupation all affect therapy. This article discusses the historical data, clinical findings, diagnostics, treatment, and farriery when presented with a horse showing lameness originating from the caudal region of the foot.