Summary
Objective: To report the successful surgical correction of severe bilateral metacarpophalangeal
valgus angular limb deformities in a seven-month-old intact male alpaca cria using
curved osteotomies stabilized with type II external skeletal fixation.
Methods: Using a 21 mm crescentic shaped oscillating saw blade, bilateral osteotomies were
performed in the distal metaphyses of the fused third and fourth metacarpal bones
to correct valgus angular limb deformity of the metacarpophalangeal joints. Axial
alignment of each limb was achieved by medially rotating the distal metacarpus in
the frontal plane along the curved osteotomies. The osteotomies were stabilized using
type II external skeletal fixators.
Results: The alpaca was immediately weight-bearing following the surgical procedure and no
to minimal lameness was observed during healing of the osteotomies. Evaluation at
five and 10 months following the surgery demonstrated acceptable axial alignment in
the left forelimb while moderate to severe varus deformity (overcorrection) was observed
in the right.
Clinical significance: Curved osteotomy of the distal metacarpus stabilized with type II external skeletal
fixation can provide a favourable outcome in older alpaca crias affected with metacarpophalangeal
angular limb deformities. Placement of the distal transfixation pins relative to the
metacarpal physes should be carefully evaluated as over-correction is possible, especially
if growth -potential remains in only one physis of the fused third and fourth metacarpal
bones.
Keywords
Angular limb deformities - alpaca - external skeletal fixation - osteotomy
