Traditional technique on decompression, the decompression range is the area of two red lines, due to the defect on the operating instruments, the removal range of the femoral head necrosis lesion is limited, and the treatment effect is also limited This is the schematic diagram of the traditional decompression surgery range, the middle area of the red line. This is the range of decompression that can be achieved by the patented special reamer (proximal, close to the articular cartilage). After the reamer is backed off, the decompression can be performed in the middle region of femoral head necrosis, and the red circle is the decompression area, which is much larger than the decompression range of the traditional instruments. The range of necrotic lesions that can be removed in the decompression of femoral head necrosis is beyond the reach of traditional techniques. Special bone grafting instruments are used to remove the lesions in the area of femoral head necrosis and then perform compression bone grafting.