Use of radiographic measures and three-dimensional computed tomographic imaging in surgical correction of an antebrachial deformity in a dog

Abstract

A 1-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of intermittent lameness and an antebrachial angular limb deformity. The left forelimb had gross antebrachial external rotation (approx 90 degrees ) and marked procurvatum. Radiography revealed a severe partially compensated biapical antebrachial angular limb deformity. Measurements of medial proximal radial angle (MPRA) and lateral distal radial angle (LDRA) were obtained from orthogonal radiographs of the proximal and distal segments of the radius, respectively. Elbow joint-to-carpus translation was quantified. Deformities were localized and quantified by the center of rotation of angulation (CORA) method. Computed tomographic 3-dimensional image reconstructions of the antebrachium and carpus were completed to create 3 life-size stereolithographic models. 2 closing wedge radial osteotomies were performed at the level of the CORAs and stabilized with bone plates and screws. Frontal and sagittal plane alignments were corrected to 8 degrees and 15 degrees , respectively (reference limits, 0 degrees to 8 degrees and 8 degrees to 35 degrees , respectively). The MPRA was corrected from 55 degrees to 68 degrees , and LDRA was corrected from 32 degrees to 76 degrees (values considered normal are approx 85 degrees and 87 degrees , respectively). Elbow joint-to-carpus translation was improved by 42.5%. After 8 weeks, radiography revealed bone union. Owners considered the outcome acceptable, on the basis of limb appearance and lack of lameness at 1 year after surgery. A segmental radiographic planning technique combined with the CORA method, computed tomography, and stereolithography may be useful in the characterization of and planning corrective surgery for forelimb deformities in dogs.