King, R. J., Makrides, P., Gill, J. A., Karthikeyan, S., Krikler, S. J. and Griffin, Damian R.. (2009) A novel method of accurately calculating the radiological magnification of the hip. Journal of Bone and Joint Surgery - British Volume, Vol.91-B (No.9). pp. 1217-1222. ISSN 0301-620X

Abstract

We have developed a novel method of calculating the radiological magnification of the hip using two separate radio-opaque markers. We recruited 74 patients undergoing radiological assessment following total hip replacement. Both the new double marker and a conventional single marker were used by the radiographer at the time of x-ray. The predicted magnification according to each marker was calculated, as was the true radiological magnification of the components. The correlation between true and predicted magnification was good using the double marker (r = 0.90, n = 74, p < 0.001), but only moderate for the single marker (r = 0.50, n = 63, p < 0.001). The median error was significantly less for the double marker than for the single (1.1% vs 4.8%, p < 0.001). The double marker method demonstrated excellent validity (intraclass correlation coefficient = 0.89), in contrast to the single marker (0.32).

Request changes to a record

Actions (login required)

View Item