Reproducibility of BMD measurements in the prosthetic knee comparing knee-specific software to traditional DXA software: a clinical validation

TY - JOUR

T1 - Reproducibility of BMD measurements in the prosthetic knee comparing knee-specific software to traditional DXA software

T2 - a clinical validation

AU - Tjørnild, Michael

AU - Søballe, Kjeld

AU - Bender, Thomas

AU - Stilling, Maiken

N1 - Copyright © 2011 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

PY - 2011

Y1 - 2011

N2 - The aim of this study was to validate new knee-specific dual X-ray absorptiometry (DXA) software for cemented total knee arthroplasty (TKA) before initiation of a randomized controlled trial. Firstly, in a phantom study, we evaluated if cementation influenced the measured BMD (g/cm²), the scan reproducibility with the new knee-specific software, and the consequences of leg rotation around a vertical axis. Secondly, in a clinical study, we assessed the clinical reproducibility in repetitive scans performed with the new knee-specific software and with traditional spine-mode DXA software, and further compared the 2 softwares' ability to point type implant and bone edges correctly. Cementation increased the measured bone mineral density (BMD) (p <0.01). For reproducibility, the coefficient of variation (CV) was 0.52-0.70% in vitro. Leg rotation around a vertical axis significantly changed the measured BMD in most scans. Automatic point typing of implant and bone edge was of varying quality with frequent need of manual correction for both softwares. CVs of clinical reproducibility ranged from 2.78% to 6.19% for knee-specific software and from 1.45% to 6.06% for spine-mode software. We found the new knee-specific software valid for BMD measurement of the bone in proximity of cemented TKA and with clinical reproducibility and corrections of point typing similar to traditional spine-mode software.

AB - The aim of this study was to validate new knee-specific dual X-ray absorptiometry (DXA) software for cemented total knee arthroplasty (TKA) before initiation of a randomized controlled trial. Firstly, in a phantom study, we evaluated if cementation influenced the measured BMD (g/cm²), the scan reproducibility with the new knee-specific software, and the consequences of leg rotation around a vertical axis. Secondly, in a clinical study, we assessed the clinical reproducibility in repetitive scans performed with the new knee-specific software and with traditional spine-mode DXA software, and further compared the 2 softwares' ability to point type implant and bone edges correctly. Cementation increased the measured bone mineral density (BMD) (p <0.01). For reproducibility, the coefficient of variation (CV) was 0.52-0.70% in vitro. Leg rotation around a vertical axis significantly changed the measured BMD in most scans. Automatic point typing of implant and bone edge was of varying quality with frequent need of manual correction for both softwares. CVs of clinical reproducibility ranged from 2.78% to 6.19% for knee-specific software and from 1.45% to 6.06% for spine-mode software. We found the new knee-specific software valid for BMD measurement of the bone in proximity of cemented TKA and with clinical reproducibility and corrections of point typing similar to traditional spine-mode software.

KW - Absorptiometry, Photon

KW - Aged

KW - Arthroplasty, Replacement, Knee

KW - Bone Density

KW - Female

KW - Humans

KW - Knee Joint

KW - Male

KW - Middle Aged

KW - Phantoms, Imaging

KW - Predictive Value of Tests

KW - Reproducibility of Results

KW - Software

U2 - 10.1016/j.jocd.2011.01.002

DO - 10.1016/j.jocd.2011.01.002

M3 - Journal article

C2 - 21474349

SN - 1094-6950

VL - 14

SP - 138

EP - 148

JO - Journal of Clinical Densitometry

JF - Journal of Clinical Densitometry

IS - 2

ER -