Method for measuring turning angle of humerus by using multiple line of CT three-D remodelling

Abstract

A 3D reproducing method with multi-row for measuring the torsional angle of humerus head includes such steps as using the shoulder joint mode in volume reproducing technique to cut and separate scapula and obtain the reproduced 3D humerus image, drawing a circle to fit the joint surface of humerus head, drawing a line between dots A and B which are cross points between said circle and joint surface, drawing the midnormal line EF or said line AB to obtain the far-end defining line of said torsional angle, drawing a line CD between the most convex dots of internal and external upper condyles to obtain its near-end defining line, and measuring the included angle between lines EF and CD to obtain said torsional angle.

Description

technical field [0001] The invention relates to a method for measuring the torsion angle of the humeral head in orthopedic medicine, in particular to a method for measuring the torsion angle of the humeral head by using multi-row X-ray CT (X-ray computed Tomography) three-dimensional reconstruction. Background technique [0002] The retroversion angle or retrotorsion angle of the humeral head refers to the angle between the central axis of the humeral head and the line connecting the medial and medial epicondyles of the distal humerus or the trochlear axis. It is one of the core indicators of joint reconstruction surgery and has very important clinical significance. Its measurement methods include direct anatomical measurement, X-ray plain film measurement, CT two-dimensional method measurement, etc. [0003] Direct anatomical measurement: Pearl ML, Volk AG. Retroversion of the proximal humerus in relationship to prosthetic replacement arthritis. J ShoulderElbow Surg. 1995,...

AI Technical Summary

Problems solved by technology

With this method, it is difficult to accurately obtain the maximum level of the humeral head side, and the medial and medial epicondyles of the distal humerus are not displayed at the same level, so it is difficult to obtain the definition line of the torsion angle accurately. Large, requiring neutral humeral rotation, 0° extension, 0° abduction, and the X-ray beam is perpendicular to the bed surface

For these reasons, the measurement method is inaccurate and time-consuming

[0006] There are also CT three-dimensional reconstruction measurements, Boileau P, Walch G. The three-dimensional geometry of the proximal humerus. Implications for surgical technique and prosthetic design. J Bone Joint Surg (Br), 1997, 79 (5): 857-865. Use and computer The connected digital measurement device analyzed 65 specimens. The defined line of the humeral head side is the perpendicular line of the articular surface diameter (head circumference diameter). 17.9°±13.7°(-6.7°~47.5°, negative value indicates that the head twist angle is angled forward), when the distal definition line is parallel to the line connecting the medial condyle and trochlea, also known as the elbow tangent line, its measured value is 21.5°±15.1°(-10.3°~56.5°), this study clearly gave a schematic diagram of the definition line of the torsion angle of the humeral head, but did not involve how to connect the humeral head and the distal humeral medial and medial epicondyles in the standard overlooking position Overlapping in the same image, while ensuring that the bony landmarks required to define the line are clear, this also causes inaccurate measurement results

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