Summary
Total hip replacement (THR) using two different human implant designs was performed
in three ponies. Pony # 1 sustained a fracture of the ipsilateral femur and was euthanatized
40 hours after implantation of a human selfcentering hip. The same implant, with a
modified femoral prosthesis, was used in pony # 2. It luxated initially at 26 hours,
was surgically reduced after changing to a smaller diameter acetabular component,
and reluxated at day 23 when the pony was euthanatized. A modified femoral component
with a press-fit, screw-fixated acetabular prosthesis was inserted in pony # 3. This
pony was maintained for 232 days and sustained over 400,000 cycles on the prosthesis
by being exercised daily on a mechanical walker. We conclude that THR is feasible
in ponies and small horses and would allow this size of animal to be used as a research
model for hip replacement in heavy human beings.
Total hip replacement (THR) was evaluated in three ponies as a model for studying
THR problems in humans and for the management of coxofemo-ral disease in small Equidae.
A modified cemented human femoral component, with a press-fit acetabular component,
was maintained in one pony for 232 days, sustained over 400,000 cycles, and established
the feasibility of THR in this species.
Keywords
Equine - Total hip replacement
