662 
LUXATION OF THE FEMUR. 
articular surfaces. Bucher’s observations show that rupture of the liga¬ 
mentum teres is often followed by severe lameness. Two horses which he 
saw with this rupture were unable to support weight on the diseased limb. 
One rested the point, the other the side of the toe, on the ground; the hock 
was excessively extended, and the phalanges fixed in a position of marked 
plantar flexion. It is not quite certain, however, whether these symptoms 
„were exclusively dependent on rupture of the ligamentum teres. Wyman 
and Lusk saw complete luxation of the femur in the mule. 
Amongst the causes are violent movement of the limb on the hip- 
joint, excessive flexion or extension in falling, and sometimes excessive 
lateral movement (ab- and ad- duction). The head of the joint, in 
quitting the acetabular cavity, does not always move in the same 
direction, but may take a variety of positions, giving rise not 
only to peculiarities in the symptoms, but influencing prognosis and 
treatment. 
Symptoms. I he displaced limb is sometimes lengthened, sometimes 
shortened, sometimes fixed in a position of adduction, sometimes in 
one of abduction. Its mobility in certain directions may be limited, 
whilst in certain others it may be abnormally increased. This resistance 
to manipulation distinguishes luxation from fracture, a distinction which 
is strengthened by the absence of crepitation. In any case, freedom of 
movement is lost. Luxation is always accompanied by marked lameness 
when the limb is carried (swinging leg lameness), though there is also 
more or less inability to sustain weight. 
After a varying interval the hip-joint appears swollen, though the 
swelling is occasionally replaced by a depression, whilst the upper 
trochanter appears displaced, being sometimes more prominent, some¬ 
times sunk in the masses of soft tissue. The skin over and around the 
hip-joint is either very tense or abnormally loose. When the bone is 
displaced into the obturator foramen, its head may be felt from the 
rectum or sheath, and is especially distinct when the limb is moved. 
Prognosis is always doubtful, and in large animals generally unfavour¬ 
able. Only during the first three days is reduction usually possible, and 
then is effected with the greatest difficulty. If attempted early, it 
sometimes succeeds in small animals, but soft tissues and blood are 
liable to enter the joint cavity and furnish great and frequently insur¬ 
mountable obstacles. After rupture of the ligamentum teres in large 
animals, relapses are very common; recovery is then exceptional, and 
the animal’s usefulness is seldom restored. % In old-standing cases, 
muscular contraction furnishes a further impediment to reduction. 
Cunningham succeeded in replacing the bone in three cows j recovery 
followed. In the case of two horses, however, he was unsuccessful. Teetz 
reduced a luxation of the femur in a goat and cured the animal, although 
treatment only commenced three weeks after the injury. Toro claims to have 
i educed an ischiatic luxation in a horse and to have effected a cure. 
