Humerus Rotation Has a Negligible Effect on Baumann Angle in a Wide Range of Rotational Positions.
Journal
Journal of pediatric orthopedics
ISSN: 1539-2570
Titre abrégé: J Pediatr Orthop
Pays: United States
ID NLM: 8109053
Informations de publication
Date de publication:
Oct 2020
Oct 2020
Historique:
pubmed:
14
7
2020
medline:
30
1
2021
entrez:
14
7
2020
Statut:
ppublish
Résumé
Rotation of the humerus out of the coronal plane is presumed to alter the Baumann angle (BA) value. Identifying the rotational limits of the humerus at which the BA can be accurately and reliably measured will circumvent repeated radiographs and unnecessary exposure to radiation, may improve patient comfort, and save time and medical resources. A retrospective chart review was performed to identify patients under the age of 18 who underwent an elbow computed tomography (CT) scan without any humeral pathology and with an open distal humeral physis. For each patient, a 3-dimensional (3D) computerized model was generated with 30% transparency to mimic a plain radiograph. These models were rotated in 10-degree increments and the BA was measured on each position. In addition, the measurements were taken on an anteroposterior radiograph for each patient. Analysis of variance and the Pearson tests were performed to locate differences and define associations. Fifteen 3D CT reconstructions were generated from 14 patients. The mean BA on the neutral position was found to be 72.2±3 degrees, which correlated with the 70.6±5.91 degrees measurement obtained on radiographs. The most extreme rotational positions on which the BA values were consistent with the neutral position values were +40 external rotation (70.97±7.01 degrees, P=1) and -70 degrees internal rotation (68.4±7.47 degrees, P=0.14). A negative correlation was found between the BA values and the extent at which the humerus was rotated from the neutral position. The variability of the BA between patients, implied by the SD of measurements on each position increased with increasing rotation from the neutral position (r=1, P<0.05). On the basis of 3D CT images, the BA is the most accurate when the arm is positioned at an exact anteroposterior position. It is reliable to measure the BA when the humerus is rotated no more than +40 degrees external rotation to -70 degrees internal rotation. This range of rotation can act as an "accurate zone" and help avoiding multiple radiographs. Level III.
Sections du résumé
BACKGROUND
BACKGROUND
Rotation of the humerus out of the coronal plane is presumed to alter the Baumann angle (BA) value. Identifying the rotational limits of the humerus at which the BA can be accurately and reliably measured will circumvent repeated radiographs and unnecessary exposure to radiation, may improve patient comfort, and save time and medical resources.
METHODS
METHODS
A retrospective chart review was performed to identify patients under the age of 18 who underwent an elbow computed tomography (CT) scan without any humeral pathology and with an open distal humeral physis. For each patient, a 3-dimensional (3D) computerized model was generated with 30% transparency to mimic a plain radiograph. These models were rotated in 10-degree increments and the BA was measured on each position. In addition, the measurements were taken on an anteroposterior radiograph for each patient. Analysis of variance and the Pearson tests were performed to locate differences and define associations.
RESULTS
RESULTS
Fifteen 3D CT reconstructions were generated from 14 patients. The mean BA on the neutral position was found to be 72.2±3 degrees, which correlated with the 70.6±5.91 degrees measurement obtained on radiographs. The most extreme rotational positions on which the BA values were consistent with the neutral position values were +40 external rotation (70.97±7.01 degrees, P=1) and -70 degrees internal rotation (68.4±7.47 degrees, P=0.14). A negative correlation was found between the BA values and the extent at which the humerus was rotated from the neutral position. The variability of the BA between patients, implied by the SD of measurements on each position increased with increasing rotation from the neutral position (r=1, P<0.05).
CONCLUSIONS
CONCLUSIONS
On the basis of 3D CT images, the BA is the most accurate when the arm is positioned at an exact anteroposterior position. It is reliable to measure the BA when the humerus is rotated no more than +40 degrees external rotation to -70 degrees internal rotation. This range of rotation can act as an "accurate zone" and help avoiding multiple radiographs.
LEVEL OF EVIDENCE
METHODS
Level III.
Identifiants
pubmed: 32658155
doi: 10.1097/BPO.0000000000001633
pii: 01241398-202010000-00011
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
e822-e826Références
Acton J, McNally M. Baumann’s confusing legacy. Injury. 2001;32:41–43.
Goldfarb CA, Patterson JMM, Sutter M, et al. Elbow radiographic anatomy: measurement techniques and normative data. J Shoulder Elbow Surg. 2012;21:1236–1246.
Omid R, Choi PD, Skaggs DL. Supracondylar humeral fractures in children. J Bone Jt Surg Am. 2008;90:1121–1132.
Kao H-K, Lee W-C, Yang W-E, et al. Clinical significance of anterior humeral line in supracondylar humeral fractures in children. Injury. 2016;47:2252–2257.
Lucas DE, Willis LM, Klingele KE. Factors predictive of early radiographic failure after closed reduction of Gartland type II supracondylar humeral fractures. J Orthop Trauma. 2013;27:457–461.
Zorrilla S, de Neira J, Prada-Cañizares A, et al. Supracondylar humeral fractures in children: current concepts for management and prognosis. Int Orthop. 2015;39:2287–2296.
Camp J, Ishizue K, Gomez M, et al. Alteration of Baumann’s angle by humeral position: implications for treatment of supracondylar humerus fractures. J Pediatr Orthop. 1993;13:521–525.
Keenan WN, Clegg J. Variation of Baumann’s angle with age, sex, and side: implications for its use in radiological monitoring of supracondylar fracture of the humerus in children. J Pediatr Orthop. 1996;16:97–98.
Pace JL, Wiater B, Schmale G, et al. Baumann angle and radial-ulnar overlap: a radiographic study to control for the angle of the x-ray beam. J Pediatr Orthop. 2012;32:467–472.
O’Driscoll SW, Spinner RJ, McKee MD, et al. Tardy posterolateral rotatory instability of the elbow due to cubitus varus. J Bone Jt Surg. 2001;83:1358–1369.
Beuerlein MJ, Reid JT, Schemitsch EH, et al. Effect of distal humeral varus deformity on strain in the lateral ulnar collateral ligament and ulnohumeral joint stability. J Bone Joint Surg Am. 2004;86:2235–2242.
Silva M, Pandarinath R, Farng E, et al. Inter- and intra-observer reliability of the Baumann angle of the humerus in children with supracondylar humeral fractures. Int Orthop. 2010;34:553–557.
Suangyanon P, Chalayon O, Worawuthangkul K, et al. Pediatric elbow measurement parameters: evaluation of the six angles in inter- and intra-observer reliability. J Clin Orthop Trauma. 2019;10:792–796.