Page 57 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

32 CHAPTER 1

VetBooks.ir 1.58

Fig. 1.58 Lateromedial radiograph of the distal
limb of a middle-aged riding horse with a unilateral
forelimb lameness localised by intra-articular
analgesia to the proximal interphalangeal joint. Note
the periarticular osteophyte formation, change in
joint contour and extra-articular new bone formation
typical of low-motion OA in this joint.

1.59

Fig. 1.59 Lateromedial radiograph of a
metacarpophalangeal joint of a horse suffering with
persistent lameness localised to this joint. This joint
has many of the radiographic changes of chronic
high-motion degenerative joint disease with decreased
joint space, subchondral sclerosis, modelling of the
articular margins of the proximal sesamoid bones and
evidence of chronic enlargement of the joint capsule
on the dorsal and palmar aspects of the distal third
metacarpus. Note the non-displaced apical proximal
sesamoid bone fracture, presumed to be the initiating
factor for the OA.

complete) via cartilage loss rather than reduced joint bone sclerosis and/or lysis, periarticular osteo-
motion. Joint fibrosis only may occur. Treatment phytosis (Fig. 1.59), osteochondral intra-articular
options for both types of joints will be discussed in fractures and finally joint ankylosis. Radiological
the relevant chapters on conditions of the limbs. changes tend to reflect a later stage of pathological
Radiography of joints affected by OA may events in OA and it is well recognised that a lack of
reveal narrowing of the joint space, subchondral correlation exists between arthroscopically evident