CT Scan Method Accurately Assesses Humeral Head Retroversion

Abstract

Humeral head retroversion is not well described with the literature controversial regarding accuracy of measurement methods and ranges of normal values. We therefore determined normal humeral head retroversion and assessed the measurement methods. We measured retroversion in 65 cadaveric humeri, including 52 paired specimens, using four methods: radiographic, computed tomography (CT) scan, computer-assisted, and direct methods. We also assessed the distance between the humeral head central axis and the bicipital groove. CT scan methods accurately measure humeral head retroversion, while radiographic methods do not. The retroversion with respect to the transepicondylar axis was 17.9 degrees and 21.5 degrees with respect to the trochlear tangent axis. The difference between the right and left humeri was 8.9 degrees. The distance between the central axis of the humeral head and the bicipital groove was 7.0 mm and was consistent between right and left humeri. Humeral head retroversion may be most accurately obtained using the patient's own anatomic landmarks or, if not, identifiable retroversion as measured by those landmarks on contralateral side or the bicipital groove.

Correlation between the retroversion of the humeral head and the orientation of the intertubercular sulcus: a CT scan anatomical study

“…Methods of measurement have included direct anatomic [13,15], radiographic [4,14], ultrasound [10], computed tomography scan [3,8], MRI [6], and computer-assisted methods [5,19,21,22]. Boileau et al [2] showed that the radiographic method overestimated the humeral head retroversion relative to the computer-assisted method. However, there was no difference between humeral head retroversion obtained by the CT scan method, the direct method, and the computer-assisted method.…”

Position of shoulder arthroplasty and clinical outcome in proximal humerus fractures

“…Clinically, reestablishing normal retroversion is essential when implanting a humeral prosthesis for any indication, but particularly in fractures of the proximal humerus [1,2,7,[11][12][13]. Correct retroversion of the humeral component is important because it affects the position of the instant center of rotation [1,2,14], the stability of the joint [9], and the amount of external rotation [15].…”

Estimation of the angle of humeral torsion from digital images of dry humeri of South Indian origin

“…The accuracy and reliability of the methods used in the present study cannot of course be compared to methods using sophisticated instruments and complex computer-assisted three dimensional reconstructions. [12,13,25] Also the accuracy of the present study could have been improved if an image analysis program such as NIH Image or ImageJ had been used.…”

“…[l,5,8,10-13] However, not many studies have analyzed the reliability and repeatability of the method. [12,13,21,25] The most commonly used measure of the magnitude of error associated with a certain measurements is the TEM, which is the square root of the measurement error variance. [29] It is expressed in the same unit of measurement as used in the original measurement.…”

“…[30] Some authors suggest that the acceptable R value has to be set depending on the investigators particular purpose. [32] In a study conducted by Boileau et al, [25] two observers measured the humeral head retroversion in 10 specimens. Using the computer-assisted method, the standard deviation for both intra-and inter observer error was less than 1° for angular measurements.…”