Optimization study of Young's-modulus gradient stem for preventing bone loss after total hip arthroplasty

2015 Fiscal Year Final Research Report

• Project/Area Number: 26750148
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Biomedical engineering/Biomaterial science and engineering
• Research Institution: University of Miyazaki
• Principal Investigator: Yamako Go 宮崎大学, テニュアトラック推進機構, 助教 (50452074)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 人工股関節 / ステム / 低弾性 / ストレスシールディング / 初期固定性

Outline of Final Research Achievements

Stress shielding-related proximal femoral bone loss after total hip arthroplasty occurs because of differences in the stiffness of metallic alloy stems and host bone. To overcome this, we fabricated a low-modulus stem from newly developed β-type Ti-33.6Nb-4Sn alloy (TNS). We evaluated its compressive and bending stiffness, stress shielding, and initial stability compared with a similar Ti-6Al-4V alloy stem. Bending stiffness of the TNS stem decreased gradually from the proximal to the distal region and was < 53% that of the Ti-6Al-4V stem, indicating gradation of Young’s modulus. The TNS stem decreased stress shielding in the proximal calcar region. The initial stabilities of the stems were comparable. With regard to reduction in stem length, there is a tradeoff between stress shielding and initial stability. These findings indicate that the TNS stem with gradation of Young’s modulus minimizes the proximal femoral bone loss and improves long-term stability.

Free Research Field

生体力学