The effect of cortical thickness and thread profile dimensions on stress and strain in bone-anchored implants for amputation prostheses
Artikel i vetenskaplig tidskrift, 2022

Skeletal attachment of limb prostheses ensures load transfer between the prosthetic leg and the skeleton. For individuals with lower limb amputation, these loads may be of substantial magnitude. To optimize the design of such systems, knowledge about the structural interplay between implant design features, dimensional changes, and material properties of the implant and the surrounding bone is needed. Here, we present the results from a parametric finite element investigation on a generic bone-anchored implant system of screw design, exposed to external loads corresponding to average and high ambulatory loading. Of the investigated parameters, cortical thickness had the largest effect on the stress and strain in the bone-anchored implant and in the cortical bone. 36%–44% reductions in maximum longitudinal stress in the bone-anchored implant was observed as a result of increased cortical thickness from 2 mm to 5 mm. A change in thread depth from 1.5 mm to 0.75 mm resulted in 20%–22% and 10%–18% reductions in maximum longitudinal stress in the bone-anchored implant at 2 mm and 5 mm cortical thickness respectively. The effect of changes in the thread root radius was less prominent, with 8% reduction in the maximum longitudinal stress in the bone-anchored implant being the largest observed effect, resulting from an increased thread root radius from 0.1 mm to 0.5 mm at a thread depth of 1.5 mm. Autologous transplantation of bone tissue distal to the fixture resulted in reductions in the longitudinal stress in the percutaneous abutment. The observed stress reduction of 10%–31% was dependent on the stiffness of the transplanted bone graft and the cortical thickness of surrounding bone. Results from this investigation may guide structural design optimization for bone-anchored implant systems for attachment of limb prostheses.

Osseointegrated prostheses for the rehabilitation of amputees (OPRA)

Direct skeletal attachment

Osseointegration

Bone-anchored limb prostheses

Finite Element Analysis

Författare

Alexander Thesleff

Center for Bionics and Pain Research

Chalmers, Elektroteknik, Signalbehandling och medicinsk teknik, Medicinska signaler och system

Integrum AB

Max Jair Ortiz Catalan

Sahlgrenska universitetssjukhuset

Center for Bionics and Pain Research

Chalmers, Elektroteknik, System- och reglerteknik, Bionik

Rickard Brånemark

Sahlgrenska universitetssjukhuset

Massachusetts Institute of Technology (MIT)

Journal of the Mechanical Behavior of Biomedical Materials

1751-6161 (ISSN)

Vol. 129 105148

Ämneskategorier

Odontologi

Biomaterialvetenskap

Medicinska material och protesteknik

DOI

10.1016/j.jmbbm.2022.105148

PubMed

35248873

Mer information

Senast uppdaterat

2022-03-15