W. Rich Redding

Nonseptic diseases associated with the hoof complex: keratoma, white line disease, canker, and neoplasia.

This article addresses nonseptic diseases associated with the hoof complex, namely keratoma, white line disease, canker, and neoplasia. Keratoma is an uncommon cause of lameness, which may be surgically removed. White line disease, a keratolytic process on the solar surface of the hoof, is treated with therapeutic farriery and resection of the hoof wall when appropriate. Equine canker is an infectious process that results in development of a chronic hypertrophy of the horn-producing tissues. Neoplasia involving the equine foot is rare, and melanoma is the most common type of neoplasm reported.

ELASTOGRAPHIC EVALUATION OF NATURALLY OCCURING TENDON AND LIGAMENT INJURIES OF THE EQUINE DISTAL LIMB.

Compression elastography is an ultrasonographic technique that estimates tissue strain and may have utility in diagnosing and monitoring soft tissue injuries in the equine athlete. Recently, elastography has been proven to be a feasible and repeatable imaging modality for evaluating normal tendons and ligaments of the equine distal forelimb. The purposes of this prospective study were to investigate the ability of elastography to detect spontaneously occurring lesions of equine tendons and ligaments diagnosed with magnetic resonance imaging (MRI) and gray-scale ultrasound (US) and to characterize the differences in the elastographic appearance of acute vs. chronic injuries. Fifty seven horses with a total of 65 lesions were evaluated. Images were assessed quantitatively and qualitatively. Acute lesions were found to be significantly softer (P < 0.0001) than chronic lesions (P < 0.0001) and the stiffness of lesions increased with progression of healing (P = 0.0138). A negative correlation between lesion hypoechogenicity and softness was appreciated with more hypoechoic lesions appearing softer (P = 0.0087) and more hyperechoic regions harder (P = 0.0002). A similar finding occurred with increased signal intensity on short tau inversion recovery (STIR) and proton density (PD) MRI sequences correlating with increased softness on elastography (P = 0.0164). Using US and MRI as references, commonly encountered soft tissue injuries of the equine distal limb could be detected with elastography. However, elastography was limited for detecting small, proximal injuries of the hindlimb proximal suspensory ligament. Elastographic evaluation of equine tendons and ligaments may allow better characterization of lesion chronicity and severity, and sequential examinations may optimize lesion management, rehabilitation, and return to training.

Septic Diseases Associated with the Hoof Complex: Abscesses, Punctures Wounds, and Infection of the Lateral Cartilage

Hoof abscesses are probably the most common cause of acute severe lameness in horses encountered by veterinarians and farriers. Most affected horses show sudden, severe (acute) lameness; the degree of lameness varies from being subtle in the early stages to non-weight bearing. There is still debate between the veterinary and farrier professions as to who should treat a hoof abscess and the best method to resolve the abscess. Puncture wounds to the sole of the foot can introduce bacteria and debris to the solar surface of the distal phalanx and produce a fracture or a septic pedal osteitis.

FEASIBILITY AND SAFETY OF CONTRAST-ENHANCED ULTRASOUND IN THE DISTAL LIMB OF SIX HORSES.

Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra-arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra-arterial injections. Intra-arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases.