The first use of ultrasonography in horses was dedicated to the management of reproduction in mares. Then, since 1983, this technique was used for the diagnosis and documentation of tendon injuries (Rantanen et al. 1983). At the beginning of the ‘90’s ultrasonographic assessment of joint disorders has been quickly developed (Denoix 1989a; 1989b; 1991; Denoix et al. 1993a; 1993b). The diagnostic data obtained with this technique have brought in depth changes in the knowledge of injuries responsible for pain in the anatomic structures of the equine locomotor system and in the understanding of their etiopathogenesis.
Technologic improvement of ultrasound machines and image resolution has continuously increased the diagnostic capabilities of ultrasonography and enlarged the field of its applications. Now this technique is essential within the different modalities that can be used for the diagnosis of the causes of lameness and performance limitations in race, sport and pleasure horses.
Between 1988 and 2009, about 20 000 clinical cases has been examined using ultrasonography. Through these exams numerous new clinical entities have been discovered and are now confirmed with the use ofmodern cross-sectional imagingmodalities such as magnetic resonance imaging and CT scan.
GENERAL INDICATIONS OF ULTRASONOGRAPHIC EXAMINATION OF EQUINE JOINTS
The first joint areas investigated with ultrasonography in horses have been themetacarpophalangeal region (fetlock joint) (Denoix 1989a; 1993; Busoni et al. 1996; Denoix et al. 1996a) and the femorotibiopatellar (stifle) joint (Denoix et al. 1994a; Denoix & Lacombe, 1996; Denoix et al. 1996b). Soon, other regions such as the carpus (Denoix & Audigié, 1996), shoulder, tarsus and foot (Denoix et al. 1994b; Denoix 1996; Denoix & Busoni,1998; Busoni & Denoix, 2001) have been investigated systematically in an attempt to identify new pathologic entities responsible for pain that were not known because of the limitations of radiography.
The general objective was to improve the diagnosis and knowledge of painful lesions in horses and to develop a complementary and alternative technique to more invasive approaches such as arthrography or arthroscopy. Ultrasonography is always indicated when the origin of the pain has been demonstrated or suspected with the clinical examination (and especially the diagnostic analgesic techniques).
Nowadays, this technique is systematically associated with radiography for the evaluation of any joint disorder. Even when radiographic findings are identified, an ultrasonographic exam is performed for the assessment of articular or periarticular soft tissues injuries, evaluation of bone and articular surfaces and to get a more complete screening of the area(s) of interest. Combined data may be essential when the prognosis and the ...