Diagnosis of Femorotibial Injuries in Horses

Summary
The stifle joint presents a lot of soft tissues that cannot be imaged with radiography. Therefore, the use of ultrasonography to examine this joint may provide useful complementary information that can be essential for the diagnosis and management of many stifle conditions.
The purpose of this paper is to present the ultrasonographic technique to image the ligaments and tendons of the femorotibial joint, to show the reference ultrasonographic images and to present the main clinical conditions that can be diagnosed with this technique. The use of ultrasonography has considerably improved the diagnosis and knowledge of ligament and tendon injuries in the stifle.

Introduction
Injuries of the equine stifle are frequent causes of hind limb lameness. The femorotibial (FT) joint is an underestimated site of lesions causing lameness. Examination with radiography has tremendous limitations because of the number of soft tissues that cannot be seen with this procedure. The interest of ultrasonography in the diagnosis and management of stifle injuries has been demonstrated (Denoix et al 1993, Dik 1995, Denoix 1996). This easy and non invasive procedure can be easily performed in the field with portable machines (Denoix and Audigié 2003, Hoegaerts et al 2005).
The specific purposes of this paper are to present the technique and reference ultrasonographic images of the FT joint, and to show the main clinical conditions that can be diagnosed with this modality.

Indications
Indications for performing imaging evaluation of the stifle in clinical cases are based on the results of physical, dynamic examination, diagnostic analgesia and/or scintigraphic examination. In this process, ultrasonography is now systematically associated to radiography. Therefore, this procedure is used in a lot of cases presented with:
- synovial fluid distension, local deformation,
- pain to mobilisation during flexion or retraction of the hind limb,
- positive intraarticular analgesia with or without radiographic findings,
- radiographic findings such as subchondral bone cyst, femorotibial collapse or instability, to check for associated soft tissues injuries,
- positive findings on scintigraphic images.  [...]