The treatment options are classified into two main categories, joint preserving techniques and non-joint preserving procedures. Non-joint preserving techniques are typically chosen in advanced stage osteonecrosis. These techniques include arthrodesis or joint fusion, talectomy or removal of all or a portion of the talus, and arthroplasty or a joint resurfacing. Joint preserving techniques include core decompression, vascular bone grafting and non-vascular bone grafting. These techniques are typically preferred for younger populations and early stage osteonecrosis. One variation of core decompression, described as percutaneous drilling, has been the subject of recent attention as it has been successful in treating osteonecrosis in the femoral head, knee, shoulder, and ankle. This technique differs slightly from other core decompression techniques in that it uses smaller drill bits and is thus less invasive and removes less bone.