Improving stress shielding following total hip arthroplasty by using a femoral stem made of β type Ti-33.6Nb-4Sn with a Young's modulus gradation

JOURNAL OF BIOMECHANICS

卷:63

Article

Yamako, Go¹  Janssen, Dennis²  Hanada, Shuji³  Anijs, Thomas²  Ochiai, Kiyohide⁴  Totoribe, Koji⁵  Chosa, Etsuo⁵  Verdonschot, Nico^2,6 

[1] Univ Miyazaki, Org Promot Tenure Track, 1-1 Gakuen Kibana Dai Nishi, Miyazaki 8892192, Japan

[2] Radboud Univ Nijmegen, Med Ctr, Radboud Inst Hlth Sci, Nijmegen, Netherlands

[3] Tohoku Univ, Inst Mat Res, Sendai, Miyagi, Japan

[4] Mizuho Corp, Tokyo, Japan

[5] Univ Miyazaki, Div Orthoped Surg, Dept Med Sensory & Motor Organs, Fac Med, Miyazaki, Japan

[6] Univ Twente, Lab Biomech Engn, Fac Engn Technol, Enschede, Netherlands

关键词: Total hip arthroplasty;    Stress shielding;    Low modulus stem;    Bone remodeling;    Finite element analysis;   

DOI  :  10.1016/j.jbiomech.2017.08.017

来源: Elsevier

【 摘 要 】

Stress shielding-related bone loss occurs after total hip arthroplasty because the stiffness of metallic implants differs from that of the host femur. Although reducing stem stiffness can ameliorate the bone resorption, it increases stress at the bone-implant interface and can inhibit fixation. To overcome this complication, a novel cementless stem with a gradient in Young's modulus was developed using Ti-33.6Nb-4Sn (TNS) alloy. Local heat treatment applied at the neck region for increasing its strength resulted in a gradual decrease in Young's modulus from the proximal to the distal end, from 82.1 to 51.0 GPa as calculated by a heat transfer simulation. The Young's modulus gradient did not induce the excessive interface stress which may cause the surface debonding. The main purpose of this study was to evaluate bone remodeling with the TNS stem using a strain-adaptive bone remodeling simulation based on finite element analysis. Our predictions showed that, for the TNS stem, bone reduction in the calcar region (Gruen zone 7) would be 13.6% at 2 years, 29.0% at 5 years, and 45.8% at 10 years postoperatively. At 10 years, the bone mineral density for the TNS stem would be 42.6% higher than that for the similar Ti-6A1-4V alloy stem. The stress-strength ratio would be lower for the TNS stem than for the Ti-6A1-4V stem. These results suggest that although proximal bone loss cannot be eliminated completely, the TNS stem with a Young's modulus gradient may have bone-preserving effects and sufficient stem strength, without the excessive interface stress. (C) 2017 Elsevier Ltd. All rights reserved.

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