Case
Study - Valgus
Leg Straightening Surgery in Foals
Some offspring of certain breeds may
be born with a knock-kneed appearance which is called carpus valgus.
In many instances
when the deformity is
not severe, the normal exercising foal will straighten its knees over the
first few weeks to a month or two. In less common instances the deformity
becomes static or worse. If an early decision for correction is made, the
foal will grow up to have an athletic career. The simplest procedure for
correction is called periosteal stripping. This method uses a release of
tension of the periosteum on the lateral side of the distal radius. It
can be done under short acting general anesthetic.
The periosteum is incised
in an inverted “T” fashion just above the growth plate of
the distal radius. Skin staples are used to close the skin incision and
compressive bandages are applied over antibiotic dressings.
Usually the improvement is noticed over the next month and
no further correction is needed. In the instance of severe deformity, or
an older foal that is not correcting on his own or after stripping, implantable
hardware is used to slow the growth on the inside of the knee. This requires
longer anesthesia, and bone screw implants and wires that have to be removed
when the leg has straightened. I have used this technique also for foals
with the opposite deformity (bow-legged) carpus varus.
The photograph of the foal on the left is an example of waiting too long
to make the decision for surgery or the deformity requires the stablization
of the medial aspect of the growthline by implanting orthopedic devices
which will be removed at the time the leg is straight. In these cases there
is sometimes some compromise of the joint, and preoperative radiographs
may give a poor prognosis for athletic capabilities.
This was the second of her foals that we corrected. An
unexpected complication the day after surgery was a cough and mild depression.
We radio graphed his chest
and found large round lung lesions typical of Rhodococcus pneumonia. We treated
him with Azithromycin and he regained his health while his legs straightened.
It’s always uplifting when you can “beat the odds.”
The photograph to the left shows the bandages applied to cover the incisions
right after surgery. The legs are not straightened yet, but continued to improve
progressively over the next 8-10 weeks. The colt was sent out of the area. A
final follow-up photograph is not available.
