RESEARCH ARTICLE
Taguchi Loss Function for Varus/Valgus Alignment in Total Knee Arthroplasty
Srinu Kusuma, Andrew G. Urquhart, Richard E Hughes*
Article Information
Identifiers and Pagination:
Year: 2009Volume: 3
First Page: 39
Last Page: 42
Publisher ID: TOBEJ-3-39
DOI: 10.2174/1874120700903010039
Article History:
Received Date: 13/6/2009Revision Received Date: 9/8/2009
Acceptance Date: 11/8/2009
Electronic publication date: 7 /9/2009
Collection year: 2009
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
Methods of designing equipment to improve quality have been developed by Taguchi. A key feature of these methods is the development of loss function, which quantifies the financial cost (loss) resulting from deviations from target dimensions. Total knee arthroplasties can fail due to prosthetic component malalignment. A Taguchi loss function for varus/valgus alignment of the prosthesis and revision rates was developed. Six studies were identified from a comprehensive literature search. Varus and extreme valgus alignments correlated with an increased percentage of prosthetic failure. A loss function of L( y) = $326.80y2 , where y was deviation from ideal varus/valgus angle, was determined. The expected loss function was was the mean deviance from the ideal varus/valgus angle and s2 was the variance in varus/valgus angle. This loss function was used to estimate the cost savings of using computer-assisted surgical navigation in total knee arthroplasty (TKA). The average savings of a navigated TKAversus a conventional TKA, based on the expected loss equation derived from the Taguchi loss function, was $2,304 per knee. The expected loss function derived here can serve as a tool for biomedical engineers seeking to use Taguchi quality engineering methods in designing orthopaedic devices.