Apache is a skewbald, warmblood cross gelding who suffered a relatively unusual lameness and subsequently was diagnosed with a congenital (inherited) abnormality that required invasive surgery to resolve it. He was 3 years old at the time he first presented lame to his owner. Up to this point Apache had been sound and had not needed any veterinary attention at all. His lameness coincided with him being broken to ride and a gradual increase in workload.
When we first saw Apache for this lameness he had been intermittently lame for a few weeks but it had become acutely a lot worse as he had recently started his schooling work and been shod for the first time. During the examination he was trotted up and found to be 6/10 lame on his left fore leg, which is a severely painful grade indicating that he had a significant problem and needed urgent pain management. On closer examination he displayed an exaggerated reaction to squeezing his left fore foot with the hoof testers, an instrument used to detect foot pain, showing that his problem lay inside his hoof capsule. He had no reaction in his right fore which ruled out diseases that would affect both feet traditionally e.g. laminitis.
Problems that can affect 1 foot are numerous but commonly include sub-solar abscesses, bruising, nail bind (when shod), penetrating wounds, pedal osteitis (infection of the pedal bone) and deep digital flexor tendon injury. There is often difficulty at first examination of a painful foot in distinguishing these diseases due to the fact that you cannot see or palpate structures through the hoof capsule. Apache had no outward sign of an abscess or penetration and none of the nails appeared to be too tight in his shoe so we elected to take a conservative approach to begin with and progress quickly to some detailed imaging and investigation if he failed to improve. Apache was on complete rest for 1 week with anti-inflammatory medication and then examined again to assess his progress. On examination of the affected foot Apache still displayed no obvious evidence of what was causing his pain but he still reacted significantly to application of the hoof testers despite being on his medication and having had 1 weeks rest. We decided to take some x-rays of the foot at this point, potentially with a view to changing his foot balance and shoeing to give the foot more support. However, on the latero-medial view of his foot the x-ray showed some abnormality of the appearance of his pedal bone, still not typical of any common condition and then on an oblique view of the pedal the problem was very obvious. Apache had a large cyst in the outside portion of his pedal bone. A bone cyst can be present in any bone and typically contains fluid contained in a fibrous capsule. This has the effect of significantly weakening the bone that is affected and very likely causing pain as a result.
Although we had a definitive diagnosis this now meant that Apache required a surgery to remove the cyst from his pedal bone. This is the only treatment for this condition and involves giving the horse a general anaesthetic and creating a window in the bottom of the hoof by cutting away the sole. Once there is access to the pedal bone a hole is made into the cyst and the fluid drained out followed by scraping the lining of the cyst away so that it does not recur. The wound is then bandaged and a special shoe is fitted that has a solid bottom so that the wound and dressing can be kept clean. Any wound to the foot, be it traumatic or surgical, is very slowly healing and carries a high risk of wound infection and therefore failure to heal. The fact that the horse is stood on its feet most of the time and, whilst on stable rest, is likely to be walking through the urine and droppings in the stable also increases the risk of this. Very careful management and hygiene is paramount during the recovery of these cases to achieve a successful result.
Apache went home after coming through his surgery very well and we visited him to change his dressing regularly eventually removing the surgical shoe when there was a complete layer of new horn over the soft tissue. The foot was continued to be dressed using a poultice type boot over the top to prevent the wet and dirt getting into the bandage and this was conrinued until the horn formed a complete sole with the existing foot. At this stage Apache was virtually sound and we decided it was appropriate to refit the shoe and start to exercise him on a flat surface so that he did not get any pressure on the recovering area by either stones or uneven ground in the field.
Apache continues to remain sound and is getting on with his ridden work without any further problems. These congenital abnormalities are relatively uncommon but this caused a severe lameness, unexpectedly, in a young horse and was only successfully treated by an invasive surgery which, fortunately, for Apache, went very well resulting in complete recovery and no further episodes of lameness.