Treatment of a coxofemoral luxation secondary to upward fixation of the patella in a Shetland pony.

A nine-year-old Shetland pony gelding, with a history of recurrent upward fixation of the patella, suddenly developed severe lameness in its right hindlimb. A luxation of the coxofemoral joint was diagnosed by a clinical and radiographic examination. The initial treatment of the luxation by closed reduction was not maintained, and the limb was placed in an Ehmer sling for four days after a second closed reduction. This allowed the femoral head to remain in the acetabulum, although a persistent subluxation remained, presumably owing to a rupture of the round ligament. The pony remained comfortable at pasture for over two years after the reduction, until osteoarthritis of the coxofemoral joint caused it to become severely lame and it had to be euthanased.