Wide en bloc excision of proximal ulna sections is used to treat traumatic and pathological fractures of the ulna, though poor standardization of clinical treatment often results in long-term failure of such reconstructed biomechanical structures. In order to provide insight into effective ulnar reconstructive treatments, the case of an 80-year-old Chinese Han male presenting with pathological fracture caused by a proximal ulnar metastatic tumor concurrent with metastatic renal cancer complicated by occurrence in the brain and lungs is reported and contrasted with alternative treatment techniques. Wide resectioning of the proximal ulna and reconstruction with local radius neck-to-humerus trochlea transposition resulted in preservation of functionality, sensitivity, and biomechanical integrity after postsurgical immobilization, 6 weeks of passive- and active-assisted flexion, and extension with a hinged brace. The resultant Musculoskeletal Tumor Society rating score was 25 of 30 (83 %). Full sensitivity and mobility of the left hand and elbow (10° to 90° with minimally impaired supination and pronation) was restored with minimal discomfort. No evidence of local recurrence or other pathological complications were observed within a 1-year follow-up period. Efficient reconstruction of osseous and capsuloligamentous structures in the elbow is often accomplished by allografts, prosthesis, and soft tissue reconstruction, though wide variations in risk and prognosis associated with these techniques has resulted in disagreements regarding the most effective standards for clinical treatment. Current findings suggest that radius neck-to-humerus trochlea transposition offers a superior range of elbow movement and fewer complications than similar allograft and prosthetic techniques for patients with multiple metastatic cancers.