Page 233 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

208 CHAPTER 1

VetBooks.ir 1.397 affected joint compartments. In older animals that
have developed concurrent OA of the distal tar-
sal joints, a stifle joint block may have to be com-
bined with a tarsometatarsal joint block to achieve
a resolution of lameness. High-quality radiographs
are required to identify the periarticular osteo-
phytes that indicate OA and a complete radiographic
series is essential to fully characterise the joint dis-
ease that is present (Fig. 1.397). Ultrasonography
is expected to confirm the presence of osteophytes
at the joint margins and may also indicate marked
synovial hypertrophy, which is typical of chronic
joint disease. If the clinical findings on examination
are suggestive of concurrent soft-tissue or cartilage
pathology, diagnostic arthroscopy may be war-
ranted, but in most cases, it is not required.

Management
Affected horses will benefit from intra-articular
Fig. 1.397 Caudocranial radiograph of the stifle of corticosteroid medication (5–10 mg triamcinolone
a 15-year-old Cob that had a long-term lameness in acetonide injected into the medial femorotibial joint;
this leg localised to the stifle joints by intra-articular avoid in animals where corticosteroids are contraindi-
analgesia. Note the signs of chronic medial and lateral cated) and a brief period of rest followed by a rehabili-
femorotibial joint osteoarthritis with remodelling of tation programme. Where joint degeneration is more
the medial intercondylar eminence, osteophytosis of advanced, concurrent oral NSAIDs may be required
the medial edge of the lateral femoral condyle and to adequately control discomfort. As with OA in other
lateral edge of the medial femoral condyle, soft-tissue locations, the rider’s expectations and the work that is
ossification in the medial collateral ligament and required of the horse may need to be adjusted.
remodelling of the distal medial epicondyle of the
femur. (Photo courtesy Graham Munroe) Prognosis
If OA is identified at a relatively early stage, there is
a fair prognosis for the management of clinical signs
Lameness may be insidious or sudden in onset. associated with the disease, although joint degenera-
In many respects stifle OA mimics OA of the distal tion will continue. When advanced OA is present it
tarsal joints, and degeneration of both regions can be can be very difficult to treat, often leading to retire-
seen concurrently in the same individual. Palpable, ment or a reduced work-load.
mild to moderate effusion of the femoropatellar and
medial femorotibial joints is commonly found. It is FRACTURES AFFECTING THE STIFLE
common to see muscle atrophy of the affected limbs.
Definition/overview
Differential diagnosis Fractures of the stifle include fractures of the patella
Chondromalacia; distal tarsal osteoarthritis; soft- (see above), the tibial tuberosity, the trochlear ridges
tissue injuries of the medial femorotibial joint; of the femur, the femoral condyles and the intercon-
OCD; OCLLs of the medial femoral condyle dylar eminences of the tibia.

Diagnosis Aetiology/pathophysiology
As with other conditions of the stifle, a positive Fractures of the patella, tibial tuberosity, troch-
response is expected to diagnostic analgesia of the lear ridges and femoral condyles are most common