Hoof Conformation and Palmar Process Fractures of the Distal Phalanx in Warmblood Foals Adrienne S. Bhatnagar, BS, a R. Scott Pleasant, DVM, MS, DACVS, b John J. Dascanio, VMD, DABVP, DACT, b Stephanie R. Lewis, BVSc, b A. Grey, DVM, b Olivia E. Schroeder, VMD, b Kristine Doyle, MS, a Jake Hall, BS, b and Rebecca K. Splan, MS, PhD a ABSTRACT This study evaluated onset and incidence of palmar pro- cess fractures in foals and investigated corresponding changes in hoof conformation. Radiographs of 17 warmblood foals were taken at 1 week and at 2, 4, 6, 8, and 12 months of age and examined for evidence of palmar process fractures. Hoof parameters were mea- sured from the radiographs, and comparisons were made between fractured and nonfractured feet. All foals suffered at least one fracture during the study period, with an average age of 3.68  0.20 months at fracture occurrence. Hoof conformation and fracture occur- rence were not significantly correlated. Foals consis- tently demonstrated higher lateral heights in the right foot and higher medial heights in the left foot. Hoof an- gle increased until 3 months of age and then gradually dropped. Hoof-pastern axis exhibited a broken forward conformation, but approached a more correct confor- mation by 12 months of age. There was a significant reduction in variation of variables for hoof and pastern angle in both feet, and hoof-pastern axis in the right foot. Hoof conformation does not appear to be a causa- tive factor of palmar process fractures. It is possible that these fractures are a normal part of bone remodeling. Keywords: Horse; Distal phalanx; Coffin bone; Ossicles; Bone remodeling INTRODUCTION Incidence of distal phalanx fractures in adult horses has been well described and is normally attributed to trauma; however, occurrence of these fractures in foals is not as clearly understood. 1–4 Six common types of fractures of the distal phalanx were originally identified and distinctly defined. 3 Two types of fractures affect the palmar process; however, they were not commonly seen in foals. 3,4 More recently, cases of ossicles or osseous bodies in the palmar process of foals have been reported, but were not consid- ered true fractures. 3,5 Advanced diagnostics, such as digital radiology, microradiology, nuclear scintigraphy, and his- tology, have determined that properties of these ossicles are consistent with fractures. 6–8 Therefore, a seventh type of distal phalanx fractures was created to distinguish these fractures from other palmar process fractures, and are defined as nonarticular fractures of the palmar or plantar process (PP3) that begin and end at the solar margin, cre- ating a triangular or oblong fragment. 3 These fractures seem to be benign and temporary, although they are some- times associated with a club-footed conformation or tem- porary lameness. 7,9 Yovich et al identified three cases of foals with fractures that are consistent with this type of PP3 fractures. 10 In 1990, 115 of 149 (77%) Thoroughbred foals on six farms in Kentucky were diagnosed with PP3 fractures (Redden, unpublished data). In an unpublished study by Mansmann, six foals were radiographed every 2 months from 2 to 14 months of age and four of these developed PP3 fractures. In a majority of cases, fractures healed normally without extensive treatment, and clinical signs of lameness were often not associated with the fractures. 7,9,10 Kaneps et al evaluated several PP3s of Thoroughbred foals using radi- ography, microradiography, and histology to determine incidence of fractures. Only 19% of the 32 foals were diagnosed with fractures using radiographic evaluation. However, of the 16 selected for further analysis, 75% were diagnosed with fractures using microradiography and 69% using histology. 7 This indicates that more ad- vanced methods may be necessary to accurately diagnose PP3 fractures in foals. These studies also indicate that inci- dence of PP3 fractures in foals is higher than was previously believed, and therefore cause and rate of occurrence warrants further investigation. The aim of this study was to determine incidence and on- set of PP3 fractures in warmblood foals on a single, Virginia ORIGINAL RESEARCH From the Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA a ; and Department of Large Animal Clinic Sciences, Phase II Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA b . Reprint requests: Adrienne S. Bhatnagar, BS, 214 Litton Reaves Hall, Virginia Tech, Blacksburg, VA 24061. 0737-0806/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jevs.2010.05.004 Journal of Equine Veterinary Science  Vol 30, No 7 (2010) 349