Shih Tzu with left forelimb deformity fixed by single oblique

Abstract

CASE DESCRIPTION A 9-month-old 4.6-kg (10.1-lb) spayed female Shih Tzu was examined for a 4-week history of left forelimb lameness. CLINICAL FINDINGS Moderate left forelimb lameness was present when weight bearing, accompanied by buckling of the left carpal joint and moderate signs of pain with hyperextension of the elbow joint. A 32° angular deformity of the left radius in a 45° craniomedial oblique plane (equivalent to 23° valgus and 23° procurvatum) and a 55° external torsional deformity were measured on 3-D reconstructed CT images. Humeroulnar incongruity of the left elbow joint was also evident. Single oblique osteotomy (SOO) and dynamic proximal ulnar osteotomy were recommended. TREATMENT AND OUTCOME Creation of a 3-D printed bone model from reconstructed CT images aided surgical planning. The SOO was located 45° medial to the sagittal plane of the left radius at the level of the center of rotation of angulation. The SOO was oriented 32° distolaterally from the transverse plane of the radius and traversed the left ulna. The bones were rotated along the osteotomy into grossly proper alignment and stabilized with a plate and bone screws. Dynamic proximal ulnar osteotomy was then performed. Six months after surgery, radiographs showed remodeling at the SOO site and the lameness had resolved. The owners expressed satisfaction with the outcome. CLINICAL RELEVANCE In dogs with angular and torsional long bone deformities, SOO may be a viable alternative to wedge osteotomies. The SOO simultaneously addressed angular and torsional deformities without bone loss and provided rigid internal fixation.