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A Proposed Mathematical Method to Quantify y-Axis Pelvic Rotation on the Anteroposterior Radiograph
Roger R Coleman1, Mark A Lopes1,2, Derek A Lopes3
1Gonstead Clinical Studies Society, Santa Cruz, California.
Objective:
Researchers have identified potential errors in the Gonstead method's analysis of pelvic alignment resulting from y-axis rotation of the pelvis on the anteroposterior (A-P) radiograph. The purpose of this article is to propose a method that can be used to determine the magnitude of y-axis rotation of the pelvis present on the A-P radiograph.
Methods:
In this proposed method, measurements are obtained from the patient and from the lateral and A-P radiographs. With a mathematical method, these measurements are used with the focal film distance to calculate the degree of pelvic rotation present on an individual A-P radiograph.
Results:
This method may help with the accuracy of measurement of pelvic y-axis rotation on the A-P radiograph.
Conclusion:
The method proposed can be used to calculate the magnitude of pelvic y-axis rotation on an A-P radiograph.
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