382 DISEASES OF THE ARTICULATIONS 



Treatment. Treatment should be applied as early as pos- 

 sible. -Anesthetize the animal and effect replacement by 

 manipulation of the limb according to the character of the 

 luxation. The principle involved is to extend the articulation 

 in whatever direction is necessary so that the head of the 

 femur can be returned to the acetabulum. Very little can 

 be done in after-treatment except keeping the animal quiet 

 for several days. Mechanical appliances to hold the bones 

 in position have not proved satisfactory. Little can be 

 expected in the treatment of chronic cases. 



Patellar. This occurs most frequently in the dog. The 

 ligaments of the patella are not very well developed outside 

 of the middle one. Therefore, displacement is more liable to 

 occur laterally. Experience has shown that internal displace- 

 ment is by far the most common. 



Etiology. The anatomical structure of the patellar liga- 

 ments and the joint in particular make displacement easy 

 from excessive exertion or injuries. In some breeds the 

 internal femoral ridge of the patellar groove is very small; 

 therefore internal displacement is of common occurrence. 



Symptoms. The limb is held in a flexed position, and the 

 patient has difficulty in supporting weight. The flexion is 

 most apparent at the stifle joint. The position of the limb 

 is somewhat characteristic, the stifle joint adducted, the 

 hock rotated outwardly, and the lower portion of the limb 

 carried toward the median line. Examination of the stifle 

 joint will reveal the misplaced patella. When the condition 

 is bilateral the animal will show a crouching attitude, and 

 will have considerable difficulty in maintaining the standing 

 position. The animal moves with great difficulty in bilateral 

 dislocation. 



Prognosis. The prognosis should not be considered favor- 

 able owing to the difficulty in keeping the parts quiet and 

 the possibility of a recurrence of the condition. Very often 

 there is a tendency for the condition to become chronic. 



Treatment. Replacement of the patella presents very little 

 difficulty; therefore the problem of keeping the patella in 

 position until the ligaments assume 'their normal condition 

 is to be the principal aim in treatment. Replacement is 



