Retrospective evaluation of equine prepurchase examinations performed 1991-2000

REASONS FOR PERFORMING STUDY: Prepurchase examinations of horses are used increasingly as a means of evaluating future soundness. Data is lacking in the literature of the radiographic findings and results of the lameness examination of comprehensive prepurchase examinations. OBJECTIVE: To summarise the clinical and radiographic findings of prepurchase examinations and determine if radiographic findings correlated with the lameness examination and sale outcome. METHODS: Records of 510 cases were reviewed, radiographs evaluated and grades assigned the navicular bone, distal phalanx, and tarsus. Follow-up information on the horse status was obtained by telephone interviews for 173 horses. RESULTS: Thoroughbred geldings represented the most common breed and sex, mean age 8 years, mean asking price 12,439.40 dollars, and 52.8% were lame. Radiography was the most common diagnostic procedure performed (61.6%), with views of the front feet requested most often (86.6%) followed by the tarsi (68.1%). Grade 1 was most common for the navicular bone while Grade 2 predominated for the distal phalanx. The number of sound horses decreased as grades became more severe. For the tarsi, Grades 0 and 1 were most common for the proximal intertarsal and distal intertarsal/metatarsal joints, respectively. Horses with significant tarsal changes were still able to compete at their expected level. With respect to the radiographic examination, the mean +/- s.d. grade of the horses which were not lame at follow-up was 1.2 +/- 0.9 for the navicular bone and 15 +/- 0.8 for the third phalanx. The mean +/- s.d. grade of sound horses for the distal intertarsal joint was 0.7 +/- 0.6 and 1.14 +/- 0.8 for the tarsometatarsal joint. Horses for which owner follow-up was available and which had a Grade 3 score were also evaluated. For the navicular bone, 17/31 with a Grade 3 remained in active use at follow-up and for the distal phalanx 21/27 were in active use. For the distal intertarsal and tarsometatarsal joints, 20/21 with a Grade 3 were still in active use. CONCLUSIONS: Prepurchase examinations can have a significant effect on the outcome of the sale. For the navicular bone and distal phalanx, higher grades were associated with lameness. In contrast, higher grades in the tarsus were less likely to be associated with lameness. Warmbloods tended to have more extensive changes in the navicular bone and distal phalanx relative to Thoroughbreds but were not as lame. POTENTIAL RELEVANCE: Radiographic changes detected in the navicular bone, distal phalanx and tarsus should be interpreted with consideration to the clinical examination.