Coffin bone

Abstract: A thorough examination and assessment of the equine foot forms an essential part of both the physical and lameness evaluations. Because foot problems are the most common cause of lameness, the examiner must have an accurate knowledge of foot anatomy and must be willing to perform a ‘‘hands on’’ approach to appreciate fully the problems that may be encountered. There are numerous causes of pain in the foot of the horse. These causes can be arbitrarily divided into (1) conditions of the hoof wall and hornproducing tissues, (2) conditions of the third phalanx, and (3) conditions of the podotrochlear region. Hoof problems would include hoof wall defects, such as cracks that involve the sensitive tissue; laminitis (systemic), laminar tearing (local caused by hoof imbalance), and separation or inflammation of the sensitive laminae from the insensitive laminae; abscess formation; contusions of the hoof causing bruising or corn formation; neoplasia; and pododermatitis (thrush or canker). Third phalanx problems include fractures of the coffin bone (types I-VII), deep digital flexor insertional tenopathy, pedal osteitis (generalized or localized inflammation of the bone), disruption of the insertions of the collateral ligaments, cyst-like lesion formation, and remodeling disease. Conditions of the podotrochlear region have been reported to include distal interphalangeal (DIP) synovitis/capsulitis, deep digital flexor tendinitis, desmitis of the impar (distal navicular ligament) or collateral sesamoidean ligaments, navicular osteitis or osteopathy, vascular disease of the navicular arteries, and navicular fractures. The common denominator of all these conditions is that they are characterized by pain that can be localized to the hoof. Like all examinations, the evaluation of the horse with foot pain requires a thorough history.

Abstract: A finite element (FE) hoof capsule was built as a small, symmetrical forelimb hoof on IDEAS* as a model for calculation and visualisation of stress and displacement of the equine hoof capsule. The model's loading was performed according to the suspension of the coffin bone within the hoof wall (pulling force) and over the sole and frog (compressing force) with a total of 3000 N. Restraints of the model's ground nodes and surface wall nodes were defined for simulation of 4 shoeing situations: a regular horseshoe, a horseshoe with a toe clip, a horseshoe with regular side clips and a horseshoe with a toe clip and more caudally-placed side clips, all fixed to the hoof capsule with 3 nails on each side and each calculated in a tense and a loose nailed condition. Von Mises stresses were taken ranging from 1.22 N/mm2 in the weightbearing border of the side clip shoe fixed loosely to the capsule up to 16.67 N/mm2 in the hoof horn material surrounding the third nail. Further high stress zones were calculated in the proximal dorsal wall, the distal heel and the lateral hoof wall. Displacement values were taken showing movements of hoof wall, sole and frog according to the shoeing conditions. Maximal displacement was calculated in the hoof capsule shod with a regular horseshoe without a clip. Minimal displacement was found in the capsule with a toe clip and 2 side clips placed behind the 3rd nail. All models showed higher displacements when calculated with a loose nail fixation. Validation of the detailed features of the models is not yet possible. Finite element analysis (FEA) can be used practically to predict influences of various farrier techniques on the equine hoof in order to avoid possible harm to horses' feet in field studies.

Abstract: A multicentre study of 285 cases was performed to enhance the management of distal phalangeal fractures on the basis of clinical evidence. The outcome after treatment was available for 223 of the cases. Horses with a non-articular type I fracture had a better prognosis (91.7%) for return to original or expected level of use than horses with an articular type II or III fracture (69.6% and 74.1%, respectively). The prognosis for types IV and V fractures was fair (57.7% and 57.1%, respectively) and for type VI good (80%). Horses with a hindlimb fracture had a significantly greater chance of a successful outcome. No significant association between age or time to start treatment and success rate was noted. The best treatment option for types I-III fractures was a conservative approach (box rest). Type IV fractures were best treated by arthroscopic removal of the fragment. Immobilisation of the hoof did not seem to influence outcome. Radiological findings and clinical healing were not accurately correlated and the re-commencement of training should be based on clinical rather than radiological findings. Complete osseous union of the fracture was not essential for a successful return to athletic activity.

Abstract: Objective To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses. Design Retrospective study of 48 affected horses. Results Most fractures occurred on the lateral palmar process of the left forelimb or the medial palmar process of the right forelimb; 81% of horses were considered sound enough to return to training and 63% raced. Of those returning to racing, 41% competed in > 10 races, 37% in 2 to 10 races and 22% in only 1 race. There was no difference in performance before and after fracture. Twenty-four of 25 horses had a bar shoe fitted for > 50% of the treatment phase. Of those horses returning to training without a bar shoe, 89% refractured at the same site. Sixty percent of horses returning to training with a bar shoe raced successfully. The total convalescent time, the time rested in a box and the time spelled in a paddock were similar for horses returning to racing and those that did not. The age of the horse had no effect on the ability to return to racing. Conclusion The prognosis for type II fractures of the distal phalanx is guarded. It is advisable to fit a bar shoe on the horse during convalescence. Horses returning to training and racing with a bar shoe appear less likely to refracture the distal phalanx. Those horses that return to racing can perform at a level similar to that prior to fracture.