Acta chirurgiae orthopaedicae
et traumatologiae Čechoslovaca

Acta Chir Orthop Traumatol Cech. 2006; 73(1):28-33 | DOI: 10.55095/achot2006/005

Measurement of Acetabular Polyethylene Wear, Using a Universal Measuring Microscope, in Total Hip Replacement
Intra- and Inter-Observer Measurement VariabilityOriginal papers

J. GALLO^1,*, V. HAVRÁNEK², J. ZAPLETALOVÁ³, D. MANDÁT²

¹ Ortopedická klinika LF UP a FN Olomouc

² Společná laboratoř optiky UP a FZÚ AV ČR, Olomouc

³ Ústav biofyziky LF UP v Olomoci, pracoviště biometrie

PURPOSE OF THE STUDY:
The aim of the study was to present our own method of measuring acetabular polyethylene wear in total hip arthroplasty, including assessment of basic measurement characteristics. It is a well known fact that, in total hip replacement, polyethylene liners wear out with use. The rate of acetabular polyethylene wear can then be related to clinical or demographic data.

MATERIAL AND METHODS:
Our method, using a universal measuring microscope, is based on the ability of exact identification of central positions of the head of total hip replacement before implantation and after prosthesis removal. The difference between the original and final positions allows us to calculate both linear and volumetric wear of polyethylene. During one month, the same components were repeatedly measured by two independent investigators and a total of 10 ABG 1 acetabular components were checked. The results of measurements were evaluated by a series of statistical tests, including correlation and regression analyses and analysis of variance.

RESULTS:
High correlations were found among individual measurements made by each observer (r = 0.998; r = 0.973) as well as between the mean values obtained from the two observers (r = 0.996). The reliability of measurements was proved by a high correlation of the regression curve of each measurement with the "ideal" line. With two exceptions, the differences between paired measurements were not significant.

CONCLUSIONS:
Our method facilitates an in vitro measurement of polyethylene wear with considerable accuracy and high reliability.

Keywords: total hip arthroplasty, wear measurement, linear wear, volumetric wear, polyethylene, universal measuring microscope, intra-observer variability, inter-observer variability

Published: February 1, 2006  Show citation