Abstract:[Objective] To investigate the clinical outcomes of core decompression and bone grafting with a self-developed guided tre- phine set for early-middle-stage femoral head necrosis (Ficat stage I and II). [Methods] From October 2016 to October 2020, 36 patients (44 hips) underwent core decompression and bone grafting with the self-developed guided trephine set for femoral head necrosis in early and middle stage. The clinical and imaging documents were evaluated. [Results] All the patients were successfully operated on, without serious complications such as important neurovascular injury during the operation, while with the operation time of (65.2±8.4) min, blood loss of (32.5±5.6) ml, intraoperative fluoroscopy times of (20.3±3.6) times, and the hospital stay of (7.0±1.8) days. All the patients were followed up for (20.8±9.3) months on an average , and resumed weight bearing activity on the affected extremity in (5.1±0.9) months on a mean. The Har- ris score [(69.5±5.9), (80.2±7.8), (82.8±6.6), P＜0.05], hip flexion-extension range of motion (ROM) [(56.6±7.8)°, (85.5±6.3)°, (91.2±8.2)°, P＜0.05] and hip internal-external rotation ROM [(35.2±5.3)°, (56.5±6.9)°, (62.7±7.2)°, P＜0.05] significantly increased over time. Radio- graphically, 2 hips developed to Ficat stage III 1 year after surgery, and 2 hips developed femoral head collapse. [Conclusion] This self-de- veloped guided trephine set for core decompression and bone grafting has the advantages of intuitive position, precise curettage of dead bone and sufficient decompression and bone grafting, and does achieve satisfactory preliminary clinical results for femoral femoral head necrosis in early and middle stage.