Conventional Humeral Retroversion Measurements Using Computed Tomography Slices or Ultrasound Images Are Not Correlated With the 3-Dimensional Humeral Retroversion Angle

Abstract

Background:Humeral retroversion angles determined by previous techniques are varied and/or biased by morphologic variations of the proximal and distal humerus, and their validity should be revisited. To overcome the limitations of previous studies associated with 2-dimensional (2D) images and the reference axes, a 3-dimensional (3D) measurement of humeral retroversion is required. However, comparisons of 2D imaging methods with the 3D computed tomography (CT) measurement as a reference standard have not been heretofore performed.Purpose:To determine whether the 3D CT humeral retroversion angle in baseball players is correlated with conventional humeral retroversion measurements.Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:A total of 28 humeri from 14 male baseball players were used for measuring humeral retroversion. Participants underwent CT scans, and geometric bone models were created for measuring the 3D CT humeral retroversion angle. Using CT slices, the 2D CT humeral retroversion angle was also determined. Bicipital forearm angle was assessed using the indirect ultrasound technique. Linear regressions and Bland-Altman plots were used to determine whether there were agreements among 3 variables: the 3D CT retroversion, 2D CT retroversion, and bicipital forearm angles.Results:In linear regression analyses, the 3D humeral retroversion angle was not predicted by the 2D CT retroversion (R = 0.167, R 2 = 0.028, P = .395) or the bicipital forearm angle (R = 0.049, R 2 = 0.002, P = .805). The bias of these 2 methods was 20.9° and –15.3°, respectively. Regression analysis demonstrated that the bicipital forearm angle was a significant predictor of the 2D CT retroversion angle (R = 0.632, R 2 = 0.400, P < .001).Conclusion:The 3D CT humeral retroversion angle was found to be underestimated by the 2D CT retroversion angle and overestimated by the bicipital forearm angle obtained by the indirect ultrasound, although a previously observed relationship between the 2D CT retroversion and bicipital forearm angles was confirmed.Clinical Relevance:Precise measurement of humeral retroversion angle is important because retroversion has been linked to upper extremity disorders, including throwing-related shoulder and elbow disorders in baseball players.

Humeral Retroversion (Complexity of Assigning Reference Axes in 3D and Its Influence on Measurement): A Technical Note

“…Angular measurements for clinical purposes with a CT scan have documented deviations due to patient positioning. 20 – 24 Variability in measurement outcome in humeral RV has been confirmed by two cadaver studies, even to some extent with 3D reformatting software. 25 , 26 However, these studies only assessed two different positions of the humerus.…”

Ultrasonographic Measurement of Torsional Side Difference in Proximal Humerus Fractures and Humeral Shaft Fractures: Theoretical Background with Technical Notes for Clinical Implementation

“…In the sonographic measurement procedures for determining humeral torsion, the proximal joint axis is usually determined assuming a constant angular relationship using the sulcus intertubercularis as a landmark [ 4 , 6 , 8 , 9 , 10 , 11 , 12 , 13 , 17 , 34 , 37 ]. However, in part due to a differing method of determining the distal joint axis, the torsion values of the sonographic measurement methods cannot always be directly compared with each other.…”

“…In 1987, Harland described a sonographic method for measuring humeral torsion in which the torsion angle could be read directly from the ultrasound device screen [ 4 , 7 ]. This later evolved into a sonographically assisted procedure, which was described in 1995 by Ito et al In the modified technique, the torsion angle is not read directly from the screen of the device but is determined with the aid of an additionally used protractor either in relation to a horizontal [ 8 , 9 , 10 ] or a vertical [ 6 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ] reference axis. This viewpoint article aims to provide a concise review of the literature concerning ultrasonographic indirect measurements of humeral torsional side differences with technical notes for clinical implementation in cases of healed proximal humerus fractures and humeral shaft fractures.…”

Does the change of retroversion angle effect the clinical results of conservative treatment of humerus diaphyseal fractures?

“…Konservatif olarak tedavi edilen humerus diafiz kırıklarında kaynama oranlarının yüksek olduğu ve fonksiyonel sonuçların oldukça iyi olduğu bilinmektedir (1,2) . Omuz eklemi mobilitesini ve stabilitesini doğrudan etkileyen humerus retroversiyonu, humerus başı ile dirsek ekseninin oryantasyonları arasındaki açısal fark olarak tanımlanır (3)(4)(5)(6) . Literatürde proksimal humerus kırığı sonrası humerus retroversiyonunun değişimi ile ilgili çalışmalar mevcut olmakla birlikte, iyileşmiş humerus diafiz kırıklarında retroversiyondaki değişimi bilgisayarlı tomografi (BT) ile karşılaştıran bir çalışma mevcut değildir.…”