Design And Experimental Study On The Internal Stent Of Femoral Head

The femoral head is a common disease in orthopedics department,different degrees of femoral head internal cell death which caused by various reasons,leading to femoral head collapse in different degree,the patient will appear hip pain,dysfunction and other activities.Core decompression is a method for the treatment of early avascular necrosis of the femoral head,which can improve blood circulation and promote blood vessel regeneration through the release of internal pressure caused by blood circulation,but could not prevent further collapse of femoral head necrosis.To solve this problem,the femoral head stent was studied to design a new type bracket,and can be implanted in patients' bodies with osteonecrosis of the femoral head,provide mechanical support for avascular necrosis of the femoral head in patients with core decompression,reduce the bed time for patients.Three aspects as design,manufacture and mechanical experiment of the femoral head stent were studied in this paper.First of all,according to the problem of insufficient mechanical support after core decompression for early osteonecrosis of the femoral head,a method of using hemispherical titanium alloy core support was proposed.Referring to the human femoral head model,different models of hemispherical femoral head support were designed,and a set of special push tools for the bracket was designed.Secondly,according to the shape of the stent,a spherical cavity is needed to be processed in the femoral head.Therefore,a spherical opening device for the femoral head was designed.The finite element analysis of the key parts of the designed scaffold and tools was carried out by ANSYS Workbench,and the structure also was optimized.The production of hemispherical titanium alloy femoral head support used the rapid prototyping technology,the designed push tool and inner spherical hole was made and assembled,then the fabricated samples can be used to meet the design requirements.Finally,the scaffold was implanted into the bone and the mechanical experiment was carried out.The feasibility of the hemispherical core support method was verified by the design and fabrication of the hemispherical stent.The stent can be safely and reliably implanted into the predetermined position of the femoral head.The mechanical experiments showed that the loading capacity of the stent implantation after core decompression was significantly higher than that of the isolated core decompression,but it was lower than the normal femoral head bearing capacity,which provided the theoretical basis for the clinical application of the medicine.