Load response of an osseointegrated implant used in the treatment of unilateral transfemoral amputation: An early implant loosening case study

Dale L. Robinson, Lauren Safai, Vahidreza Jafari Harandi, Mark Graf, L. Eduardo Cofré Lizama, Peter Lee, Mary P. Galea, Fary Khan, Kwong Ming Tse, David C. Ackland

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Background: Osseointegrated implants for transfemoral amputees facilitate direct load transfer between the prosthetic limb and femur; however, implant loosening is a common complication, and the associated implant-bone loads remain poorly understood. This case study aimed to use patient-specific computational modeling to evaluate bone-implant interface loading during standing and walking in a transfemoral amputee with an osseointegrated implant prior to prosthesis loosening and revision surgery. Methods: One male transfemoral amputee with an osseointegrated implant was recruited (age: 59-yrs, weight: 83 kg) and computed tomography (CT) performed on the residual limb approximately 3 months prior to implant failure. Gait analyses were performed, and the CT images used to develop a finite element model of the patient's implant and surrounding bone. Simulations of static weight bearing, and over-ground walking were then performed. Findings: During standing, maximum and minimum principal strains in trabecular bone adjacent to the implant were 0.26% and −0.30%, respectively. Strains generated at the instant of contralateral toe-off and contralateral heel strike during walking were substantially higher and resulted in local trabecular bone yielding. Specifically, the maximum and minimum principal strains in the thin layer of trabecular bone surrounding the distal end of the implant were 1.15% and −0.98%, respectively. Interpretation: Localised yielding of trabecular bone at the interface between the femur and implant in transfemoral amputee osseointegrated prosthesis recipients may present a risk of implant loosening due to periprosthetic bone fracture during walking. Rehabilitation exercises should aim to produce implant-bone loading that stimulates bone remodelling to provide effective bone conditioning prior to ambulation.

Original languageEnglish
Pages (from-to)201-212
JournalClinical Biomechanics
Volume73
DOIs
Publication statusPublished - 2020
Externally publishedYes

Keywords

  • Biomechanical model
  • Finite element analysis
  • Gait
  • Lower limb amputee
  • Osseointegration

Fingerprint Dive into the research topics of 'Load response of an osseointegrated implant used in the treatment of unilateral transfemoral amputation: An early implant loosening case study'. Together they form a unique fingerprint.

Cite this