Retroversion as measured between the humeral center line and the transepicondylar line was decreased on the involved side, with a mean of −2° on the involved side compared with 20° on the uninvolved side (p < 0.001) (Fig. 4). The mean paired difference was 22° (range, −15° to 40°). There was no significant correlation between humeral retroversion and the range of passive external rotation, glenoid retroversion, or glenoid morphology type (p > 0.05 for all comparisons). There was no correlation between age and humeral retroversion using the humeral center line reference axis (r = −0.123, p = 0.594). Although not significant (p = 0.556), linear regression showed a decrease of 0.7° per year.
All measurements of version were done independently twice by two of the authors to assess repeatability and reliability of the measurements. Intraclass correlation coefficients showed good to excellent reliability and were as follows. For retroversion measured by the skew axis, the intraclass correlation coefficient for interrater reliability on the involved side was 0.944 (95% CI, 0.897 to 0.970; p < 0.001). The intraclass correlation coefficient for interrater reliability on the uninvolved side was 0.867 (95% CI, 0.754 to 0.928; p < 0.001). The intraclass correlation coefficient for intrarater reliability on the involved side was 0.949 (95% CI, 0.881 to 0.979; p < 0.001) for examiner 1 and 0.973 (95% CI, 0.935 to 0.989; p < 0.001) for examiner 2. The intraclass correlation coefficient for intrarater reliability on the uninvolved side was 0.825 (95% CI, 0.620 to 0.925; p < 0.001) for examiner 1 and 0.930 (95% CI, 0.828 to 0.972; p < 0.001) for examiner 2 (Table III).
For retroversion measured by the humeral center line, the intraclass correlation coefficient for interrater reliability on the involved side was significant at 0.881 (95% CI, 0.778 to 0.936; p < 0.001). The intraclass correlation coefficient for interrater reliability on the uninvolved side was significant at 0.863 (95% CI, 0.640 to 0.938; p < 0.001). The intraclass correlation coefficient for intrarater reliability on the involved side was significant at 0.950 (95% CI, 0.879 to 0.980; p < 0.001) for examiner 1 and 0.959 (95% CI, 0.889 to 0.984; p < 0.001) for examiner 2. The intraclass correlation coefficient for intrarater reliability on the uninvolved side was significant at 0.968 (95% CI, 0.923 to 0.987; p < 0.001) for examiner 1 and 0.951 (95% CI, 0.881 to 0.980; p < 0.001) for examiner 2 (Table III).
The first two reports on humeral retroversion in children with neonatal brachial plexus palsy showed that retroversion was increased in this patient population7,8. However, we found a reduction of retroversion, by 13° to 22° depending on the reference axes selected, in a cohort of young children under evaluation for internal rotation contractures from this injury. Our findings are in agreement with another recent study on this subject by Sheehan et al., who reported a reduction in retroversion of 17° in an older group of children, with a mean age of 11.8 years (range, 6.7 to 18.7 years)9. The mean age of subjects in our study was 3.2 years, with most of our patients <5 years of age and all patients ≤10.1 years of age. To the extent that the existing literature presents conflicting information, our study weighed strongly toward establishing that version decreases with this injury.
This information may alter surgical indications for some patients, but definitive recommendations will require further study. Most treating surgeons presently favor soft-tissue procedures for patients who present with an internal rotation contracture and minimal deformity of the glenohumeral joint. However, if it were known that such a patient also had markedly decreased humeral retroversion, a rotational osteotomy might be much more compelling. At a minimum, the prevailing recommendation to reserve humeral osteotomy for patients with the most advanced glenohumeral deformity merits reconsideration.
The complexities in measuring humeral version and the deformities that result from this condition perhaps explain the conflicting findings in the earlier literature on this subject. The developing proximal humeral articular surface often warps in the presence of an internal rotation contracture, losing symmetry, with its new shape having a long axis (the skew axis) that is directed posteriorly relative to the original orientation of the articular surface5,6. In the present study, retroversion measured on the involved side relative to the skew axis was, on average, 8° more than version referenced to the humeral center line, with a maximum difference of 42°. In contrast, retroversion measured on the uninvolved side using these different proximal reference axes had a negligible difference (<2°).
A potential limitation of the methods used in this study was the superposition of two-dimensional images slices from the proximal and distal ends of the humerus to define the retroversion angle. All existing methodologies have their limitations, but a method based on a three-dimensional reconstruction of the entire humeral bone would potentially offer the truest value of retroversion. The methods of Sheehan et al. explore the potential of such a method, statistically defining the orientation of the bone from a three-dimensional model constructed by manually segmenting the relevant anatomy9. However, the clinical utility and relevance of these statistically calculated axes remain to be established. We therefore chose to pursue a method that was consistent with the earlier literature on this subject, adding precision to the method of defining the proximal reference axis, aiming for consistency between subjects and between sides in each subject. Our reliability data suggest that these efforts were successful.
Neither the severity of the internal rotation contracture nor the extremity of the glenoid version or glenoid deformity type was correlated with the reduction in humeral retroversion. It is possible that our small sample size was underpowered to identify correlations that exist. Alternatively, it is also possible that activity-related extrinsic factors are responsible for this altered development. Just as the external rotation torque from the throwing motion alters humeral growth, increasing retroversion17,18,20-23, one could speculate that the less-used limb of a child with neonatal brachial plexus palsy would experience less external rotation torque, resulting in decreased retroversion. Further biomechanical study is required to determine which activities impart this torque. Increasing evidence from animal models further supports the theory that some of the glenohumeral version changes with this injury stem from altered use of the limb39-42.
In conclusion, we observed that humeral retroversion on the affected side commonly decreased in the presence of an internal rotation contracture secondary to neonatal brachial plexus palsy. Some earlier studies have suggested otherwise, but we believe that those conflicting results were likely due to a measurement methodological artifact. Clinical evaluation of humeral retroversion may become an increasingly important part of surgical planning, but how and if this should change surgical indications require further study.
NOTE: The authors thank Justin Klein for illustrations.
Investigation performed at the Kaiser Permanente Los Angeles Medical Center, Los Angeles, California
1. Pearl ML, Edgerton BW. Glenoid deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 1998 ;80(5):659–67.
2. Kozin SH. Correlation between external rotation of the glenohumeral joint and deformity after brachial plexus birth palsy. J Pediatr Orthop. 2004 ;24(2):189–93.
3. Pearl ML, Edgerton BW, Kon DS, Darakjian AB, Kosco AE, Kazimiroff PB, Burchette RJ. Comparison of arthroscopic findings with magnetic resonance imaging and arthrography in children with glenohumeral deformities secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 2003 ;85(5):890–8.
4. Waters PM, Smith GR, Jaramillo D. Glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 1998 ;80(5):668–77.
5. Pearl ML, Woolwine S, van de Bunt F, Merton G, Burchette R. Geometry of the proximal humeral articular surface in young children: a study to define normal and analyze the dysplasia due to brachial plexus birth palsy. J Shoulder Elbow Surg. 2013 ;22(9):1274–84. Epub 2013 Mar 9.
6. Reading BD, Laor T, Salisbury SR, Lippert WC, Cornwall R. Quantification of humeral head deformity following neonatal brachial plexus palsy. J Bone Joint Surg Am. 2012 ;94(18):e136.1-8.
7. van der Sluijs JA, van Ouwerkerk WJ, de Gast A, Wuisman P, Nollet F, Manoliu RA. Retroversion of the humeral head in children with an obstetric brachial plexus lesion. J Bone Joint Surg Br. 2002 ;84(4):583–7.
8. Scaglietti O. The obstetrical shoulder trauma. Surg Gynecol Obstet. 1938;66:868–77.
9. Sheehan FT, Brochard S, Behnam AJ, Alter KE. Three-dimensional humeral morphologic alterations and atrophy associated with obstetrical brachial plexus palsy. J Shoulder Elbow Surg. 2014 ;23(5):708–19. Epub 2013 Dec 2.
10. Cassagnaud X, Maynou C, Petroff E, Dujardin C, Mestdagh H. A study of reproducibility of an original method of CT measurement of the lateralization of the intertubercular groove and humeral retroversion. Surg Radiol Anat. 2003 ;25(2):145–51. Epub 2003 Apr 11.
11. Edelson G. Variations in the retroversion of the humeral head. J Shoulder Elbow Surg. 1999 ;8(2):142–5.
12. Edelson G. The development of humeral head retroversion. J Shoulder Elbow Surg. 2000 ;9(4):316–8.
13. Krahl VE. The torsion of the humerus; its localization, cause and duration in man. Am J Anat. 1947 ;80(3):275–319.
14. 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):857–65.
15. Pearl ML, Volk AG. Retroversion of the proximal humerus in relationship to prosthetic replacement arthroplasty. J Shoulder Elbow Surg. 1995 ;4(4):286–9.
16. Robertson DD, Yuan J, Bigliani LU, Flatow EL, Yamaguchi K. Three-dimensional analysis of the proximal part of the humerus: relevance to arthroplasty. J Bone Joint Surg Am. 2000 ;82(11):1594–602.
17. Osbahr DC, Cannon DL, Speer KP. Retroversion of the humerus in the throwing shoulder of college baseball pitchers. Am J Sports Med. 2002 ;30(3):347–53.
18. Reagan KM, Meister K, Horodyski MB, Werner DW, Carruthers C, Wilk K. Humeral retroversion and its relationship to glenohumeral rotation in the shoulder of college baseball players. Am J Sports Med. 2002 ;30(3):354–60.
19. Whiteley R, Ginn K, Nicholson L, Adams R. Indirect ultrasound measurement of humeral torsion in adolescent baseball players and non-athletic adults: reliability and significance. J Sci Med Sport. 2006 ;9(4):310–8. Epub 2006 Jun 23.
20. Whiteley RJ, Adams RD, Nicholson LL, Ginn KA. Reduced humeral torsion predicts throwing-related injury in adolescent baseballers. J Sci Med Sport. 2010 ;13(4):392–6. Epub 2009 Aug 15.
21. Yamamoto N, Itoi E, Minagawa H, Urayama M, Saito H, Seki N, Iwase T, Kashiwaguchi S, Matsuura T. Why is the humeral retroversion of throwing athletes greater in dominant shoulders than in nondominant shoulders? J Shoulder Elbow Surg. 2006 ;15(5):571–5.
22. Crockett HC, Gross LB, Wilk KE, Schwartz ML, Reed J, O’Mara J, Reilly MT, Dugas JR, Meister K, Lyman S, Andrews JR. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Am J Sports Med. 2002 ;30(1):20–6.
23. Chant CB, Litchfield R, Griffin S, Thain LM. Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion. J Orthop Sports Phys Ther. 2007 ;37(9):514–20.
24. Harrold F, Wigderowitz C. A three-dimensional analysis of humeral head retroversion. J Shoulder Elbow Surg. 2012 ;21(5):612–7. Epub 2011 Jul 23.
25. Boileau P, Bicknell RT, Mazzoleni N, Walch G, Urien JP. CT scan method accurately assesses humeral head retroversion. Clin Orthop Relat Res. 2008 ;466(3):661–9. Epub 2008 Feb 10.
26. DeLude JA, Bicknell RT, MacKenzie GA, Ferreira LM, Dunning CE, King GJ, Johnson JA, Drosdowech DS. An anthropometric study of the bilateral anatomy of the humerus. J Shoulder Elbow Surg. 2007 ;16(4):477–83. Epub 2007 Mar 23.
27. Hernigou P, Duparc F, Hernigou A. Determining humeral retroversion with computed tomography. J Bone Joint Surg Am. 2002 ;84(10):1753–62.
28. Kronberg M, Broström LA, Söderlund V. Retroversion of the humeral head in the normal shoulder and its relationship to the normal range of motion. Clin Orthop Relat Res. 1990 ;253:113–7.
29. Matsumura N, Ogawa K, Kobayashi S, Oki S, Watanabe A, Ikegami H, Toyama Y. Morphologic features of humeral head and glenoid version in the normal glenohumeral joint. J Shoulder Elbow Surg. 2014 ;23(11):1724–30. Epub 2014 May 24.
30. Debevoise NT, Hyatt GW, Townsend GB. Humeral torsion in recurrent shoulder dislocations. A technic of determination by X-ray. Clin Orthop Relat Res. 1971 ;76:87–93.
31. Cyprien JM, Vasey HM, Burdet A, Bonvin JC, Kritsikis N, Vuagnat P. Humeral retrotorsion and glenohumeral relationship in the normal shoulder and in recurrent anterior dislocation (scapulometry). Clin Orthop Relat Res. 1983 ;175:8–17.
32. Pearl ML, Edgerton BW, Kazimiroff PA, Burchette RJ, Wong K. Arthroscopic release and latissimus dorsi transfer for shoulder internal rotation contractures and glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 2006 ;88(3):564–74.
33. Hoffer MM, Phipps GJ. Closed reduction and tendon transfer for treatment of dislocation of the glenohumeral joint secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 1998 ;80(7):997–1001.
34. Kozin SH, Boardman MJ, Chafetz RS, Williams GR, Hanlon A. Arthroscopic treatment of internal rotation contracture and glenohumeral dysplasia in children with brachial plexus birth palsy. J Shoulder Elbow Surg. 2010 ;19(1):102–10.
35. Gilbert A, Brockman R, Carlioz H. Surgical treatment of brachial plexus birth palsy. Clin Orthop Relat Res. 1991 ;264:39–47.
36. Waters PM, Bae DS. The effect of derotational humeral osteotomy on global shoulder function in brachial plexus birth palsy. J Bone Joint Surg Am. 2006 ;88(5):1035–42.
37. Kirkos JM, Kyrkos MJ, Kapetanos GA, Haritidis JH. Brachial plexus palsy secondary to birth injuries. J Bone Joint Surg Br. 2005 ;87(2):231–5.
38. Shrout PE, Fleiss JL. Intraclass correlations: uses in assessing rater reliability. Psychol Bull. 1979 ;86(2):420–8.
39. Crouch DL, Hutchinson ID, Plate JF, Antoniono J, Gong H, Cao G, Li Z, Saul KR. Biomechanical basis of shoulder osseous deformity and contracture in a rat model of brachial plexus birth palsy. J Bone Joint Surg Am. 2015 ;97(15):1264–71.
40. Soldado F, Benito-Castillo D, Fontecha CG, Barber I, Marotta M, Haddad S, Menendez ME, Mascarenhas VV, Kozin SH. Muscular and glenohumeral changes in the shoulder after brachial plexus birth palsy: an MRI study in a rat model. J Brachial Plex Peripher Nerve Inj. 2012 ;7(1):9.
41. Li Z, Ma J, Apel P, Carlson CS, Smith TL, Koman LA. Brachial plexus birth palsy-associated shoulder deformity: a rat model study. J Hand Surg Am. 2008 ;33(3):308–12.
42. Kim HM, Galatz LM, Patel N, Das R, Thomopoulos S. Recovery potential after postnatal shoulder paralysis. An animal model of neonatal brachial plexus palsy. J Bone Joint Surg Am. 2009 ;91(4):879–91.