We describe patient-specific surgical guide prototyping and surgical treatment of a complex antebrachial deformity in two skeletally mature dogs presenting with chronic lameness. Computer-assisted surgery was elected to increase accuracy in the correction of the complexity deformity. Radiographs and CT scans revealed a biplane deformity with valgus, procurvatum and external torsion of the right radius in both cases. The pre-surgical planning started from the quantification of the angular deformity, computer simulated correction to end up with a rehearsal surgery on 3D printed bone models. During the surgery, the custom-made osteotomy guides closely fitted the bone, allowing for a precise corrective osteotomy, that was stabilized with two locking plates. Postoperative x-rays showed successful correction of the deformity. At the follow up recheck examinations at 8 and 12 weeks postoperatively the dogs had improved lameness, weight-bearing and progression of bone healing were observed in both dogs. Patientspecific surgical guides allowed for a satisfactory correction of the antebrachial deformity. Additional benefits of using customized surgical devices include standardization and reduced surgical time.