Device to measure intra-operatively the primary stability of cementless hip stems

L. Cristofolini, E. Varini, I. Pelgreffi, A. Cappello, A. Toni

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The primary stability of cementless prostheses is critical for the long-term outcome of the operation. Surgeons are currently driven only by their experience in evaluating the extent of stem stability achieved. The aim of the present work was to develop a new device that enables the stability of a cementless stem to be quantitatively assessed intraoperatively. The angle of the stem/femur rotation under torsion and the torque are acquired and compared in real-time to a pre-set threshold inferred from the literature. The device indicates whether the stem is stable or not. It was extensively tested and finally validated in vitro on cadaveric and composite femurs hosting different sizes of the same kind of prostheses, implanted with different levels of press-fitting. The overall accuracy (23%) takes into account not only the overall measurement error but also the variability due to differences in bone quality and stem press-fitting. This error was deemed sufficient to discriminate between stable and unstable implants.

Original languageEnglish
Pages (from-to)475-482
Number of pages8
JournalMedical Engineering and Physics
Volume28
Issue number5
DOIs
Publication statusPublished - Jun 2006

Fingerprint

Femur
Prostheses and Implants
Hip
Prosthetics
Equipment and Supplies
Torque
Measurement errors
Bone and Bones
Torsional stress
Bone
Composite materials
In Vitro Techniques
Surgeons

Keywords

  • Cementless prosthesis
  • Hip
  • Intraoperative measurement
  • Micromotion
  • Primary stability

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Psychology(all)

Cite this

Device to measure intra-operatively the primary stability of cementless hip stems. / Cristofolini, L.; Varini, E.; Pelgreffi, I.; Cappello, A.; Toni, A.

In: Medical Engineering and Physics, Vol. 28, No. 5, 06.2006, p. 475-482.

Research output: Contribution to journalArticle

Cristofolini, L. ; Varini, E. ; Pelgreffi, I. ; Cappello, A. ; Toni, A. / Device to measure intra-operatively the primary stability of cementless hip stems. In: Medical Engineering and Physics. 2006 ; Vol. 28, No. 5. pp. 475-482.
@article{2972d3f182ec4d98a365b298bb035e65,
title = "Device to measure intra-operatively the primary stability of cementless hip stems",
abstract = "The primary stability of cementless prostheses is critical for the long-term outcome of the operation. Surgeons are currently driven only by their experience in evaluating the extent of stem stability achieved. The aim of the present work was to develop a new device that enables the stability of a cementless stem to be quantitatively assessed intraoperatively. The angle of the stem/femur rotation under torsion and the torque are acquired and compared in real-time to a pre-set threshold inferred from the literature. The device indicates whether the stem is stable or not. It was extensively tested and finally validated in vitro on cadaveric and composite femurs hosting different sizes of the same kind of prostheses, implanted with different levels of press-fitting. The overall accuracy (23{\%}) takes into account not only the overall measurement error but also the variability due to differences in bone quality and stem press-fitting. This error was deemed sufficient to discriminate between stable and unstable implants.",
keywords = "Cementless prosthesis, Hip, Intraoperative measurement, Micromotion, Primary stability",
author = "L. Cristofolini and E. Varini and I. Pelgreffi and A. Cappello and A. Toni",
year = "2006",
month = "6",
doi = "10.1016/j.medengphy.2005.07.015",
language = "English",
volume = "28",
pages = "475--482",
journal = "Medical Engineering and Physics",
issn = "1350-4533",
publisher = "Elsevier BV",
number = "5",

}

TY - JOUR

T1 - Device to measure intra-operatively the primary stability of cementless hip stems

AU - Cristofolini, L.

AU - Varini, E.

AU - Pelgreffi, I.

AU - Cappello, A.

AU - Toni, A.

PY - 2006/6

Y1 - 2006/6

N2 - The primary stability of cementless prostheses is critical for the long-term outcome of the operation. Surgeons are currently driven only by their experience in evaluating the extent of stem stability achieved. The aim of the present work was to develop a new device that enables the stability of a cementless stem to be quantitatively assessed intraoperatively. The angle of the stem/femur rotation under torsion and the torque are acquired and compared in real-time to a pre-set threshold inferred from the literature. The device indicates whether the stem is stable or not. It was extensively tested and finally validated in vitro on cadaveric and composite femurs hosting different sizes of the same kind of prostheses, implanted with different levels of press-fitting. The overall accuracy (23%) takes into account not only the overall measurement error but also the variability due to differences in bone quality and stem press-fitting. This error was deemed sufficient to discriminate between stable and unstable implants.

AB - The primary stability of cementless prostheses is critical for the long-term outcome of the operation. Surgeons are currently driven only by their experience in evaluating the extent of stem stability achieved. The aim of the present work was to develop a new device that enables the stability of a cementless stem to be quantitatively assessed intraoperatively. The angle of the stem/femur rotation under torsion and the torque are acquired and compared in real-time to a pre-set threshold inferred from the literature. The device indicates whether the stem is stable or not. It was extensively tested and finally validated in vitro on cadaveric and composite femurs hosting different sizes of the same kind of prostheses, implanted with different levels of press-fitting. The overall accuracy (23%) takes into account not only the overall measurement error but also the variability due to differences in bone quality and stem press-fitting. This error was deemed sufficient to discriminate between stable and unstable implants.

KW - Cementless prosthesis

KW - Hip

KW - Intraoperative measurement

KW - Micromotion

KW - Primary stability

UR - http://www.scopus.com/inward/record.url?scp=33646478733&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33646478733&partnerID=8YFLogxK

U2 - 10.1016/j.medengphy.2005.07.015

DO - 10.1016/j.medengphy.2005.07.015

M3 - Article

C2 - 16144768

AN - SCOPUS:33646478733

VL - 28

SP - 475

EP - 482

JO - Medical Engineering and Physics

JF - Medical Engineering and Physics

SN - 1350-4533

IS - 5

ER -