Periosteal transection and stripping for treatment of angular limb deformities in foals: radiographic observations.

Radiographs of 23 foals (35 forelimbs) with carpal region angular limb deformities, which later were corrected by hemicircumferential transection of the periosteum and periosteal stripping, were evaluated as to geometric and morphologic abnormalities. Geometric evaluation included deviation angle and deviation pivot point. Morphologic abnormalities were categorized as: asymmetric width of the distal radial physis; asymmetric width of the distal radial epiphysis; carpal bone collapse or fracture; carpal bone hypoplasia; carpal bone displacement; and metacarpal bone displacement. Fifty-seven percent of limbs had radiographic lesions in the carpal joints and 20% had lesions in the metacarpus. Of all the limbs, 48% had carpal or metacarpal bone hypoplasia, 26% had carpal or metacarpal bone displacement, and 12% had carpal bone collapse or fragmentation. On long-term followup (5 months to 2 years), 83% of the foals were sound and had straight limbs, regardless of the deviation angle, deviation pivot point, or morphologic carpal bone changes. Sixty percent of the foals were in performance training. About 50% of these foals in performance training had carpal bone hypoplasia before correction of the deviation. It was concluded that geometric and morphologic radiographic interpretation should be performed before surgical correction of carpal angular limb deformities with hemicircumferential transection of the periosteum and periosteal stripping, but that epiphyseal, carpal bone, or metacarpal bone changes, severe deviation angle (20 to 29 degrees) or distal location of the pivot point should not discourage attempted surgical correction.