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

The study involves the case of a nine-year-old Shetland pony that developed severe lameness in its hindlimb due to coxofemoral luxation, a complication arising from recurrent upward fixation of its patella. Treatment by closed reduction and the use of an Ehmer sling led to temporary relief though the pony ultimately had to be euthanased due to resulting osteoarthritis.

Subject of the study

• The research focused on a Shetland pony gelding, aged nine years, who had a history of repeatedly experiencing upward fixation of the patella.
• The pony started showing signs of extreme lameness in its right hindlimb, prompting a diagnostic investigation.
• Through clinical and radiographic examinations, a luxation or dislocation of the coxofemoral joint was diagnosed which is presumed to be the cause for the severe lameness.

Treatment Employed

• Initial treatment of the luxation involved a process called closed reduction. However, this did not produce sustained results.
• To address the recurring issue, the pony’s limb was retained in an Ehmer sling for four days after a second closed reduction was done.
• This strategy allowed the pony’s femoral head to stay within the acetabulum which prevented further dislocation.
• However, a residual subluxation persisted suggesting a possible rupture of the round ligament.

Outcomes and Conclusions

• Post-treatment, the pony remained at ease when grazing at pasture for more than two years.
• However, in the long run, osteoarthritis of the coxofemoral joint developed, resulting in the pony becoming severely lame once again.
• Given the pony’s deteriorated condition and likely diminished quality of life, the decision was made to euthanise.