Humerus Rotation Has a Negligible Effect on Baumann Angle in a Wide Range of Rotational Positions

Evaluation of Gartland Classification, Baumann Angle and Anterior Humeral Line in Paediatrics Supracondylar Fractures: An Inter and Intra-Observer Reliability Study

Supracondylar fractures of the humerus are frequent paediatric injuries. The aims of this study were to evaluate the applicability and reproducibility of the Gartland and Wilkins classification, the Baumann angle (BA) and the Anterior Humeral Line (AHL). This retrospective monocentric observational study was conducted on 217 patients. Four observers assessed the pre-operative radiographs by applying the Gartland and Wilkins classification and the post-operative X-rays by measuring the BA and AHL. The kappa coefficient (K) and the Cohen's kappa were used for the reliability of the Gartland classification; the Intraclass Correlation Coefficient (ICC) for that of the BA. The AHL was evaluated in a double manner by using first the K and the Cohen's kappa and then the ICC. A total of 186 patients were eligible. Inter-observer reliability for the Gartland classification was K = 0.73-0.61 for type III, 0.65-0.61 for type Ia and 0.43-0.26 for type IIb. The Baumann angle mean value in the first data collection was 73.5 ± 6.85 (inter-observer ICC 0.74) and 72.9 ± 6.83 (inter-observer ICC 0.77) for the second data collection; AHL: inter-observer ICC 0.87 for the first evaluation and 0.80 for the second one. Gartland's classification modified by Wilkins has a high degree of reliability. BA and AHL appear reproducible and reliable.

Assessment and Validation of Anterior Humeral Line for Diagnosing Supracondylar Humerus Fractures in the Pediatric Population

INTRODUCTION

Pediatric supracondylar humerus fractures are commonly evaluated using the anterior humeral line (AHL) on a lateral radiograph. Rotational variations in radiographic projection are common due to child discomfort and could lead to changes in management based on where the AHL intersects the capitellum. The purpose of this study was to establish whether rotational variations in elbow rotation leads to significant changes in AHL position and whether drawing the AHL based on the distal humerus versus shaft is more tolerant to rotation.

METHODS

Fifty children with nonoperative supracondylar humerus fractures were identified with sub optimally positioned injury and well positioned follow-up lateral radiographs. The proportion of the bone anterior to the intersection of the AHL and the capitellum was measured using the humeral shaft versus distal humerus to guide position of the AHL. This process was repeated on ten pediatric humerus dry cadaveric specimens which were imaged in 5-degree rotational increments along the axis of the humeral shaft from -20 to +20 degrees.

RESULTS

AHL position correlated poorly when measured on rotated lateral radiographs of clinical patients versus non-rotated lateral radiographs when using the distal humerus as a guide (intraclass correlation coefficient 0.14), compared with when using the humeral shaft as a guide (intraclass correlation coefficient 0.81). When assessing the pediatric humerus dry cadavers between the 2 techniques, there was greater statistically significant variation in rotated positions compared with the neutral position in the distal humerus AHL measurement approach compared with the humeral shaft AHL measurement approach, with the mean AHL within the central third of the capitellum for more rotational positions when using the shaft compared with the distal humerus.

CONCLUSIONS

With rotated lateral elbow radiographs in supracondylar humerus fractures, utilizing the humeral shaft provides more consistent AHL measurements than utilizing the distal humerus, and thus drawing the line starting at the shaft of the humerus is recommended for surgical decision making.

Fully displaced pediatric supracondylar humerus fractures: Which ones need to go at night?

BACKGROUND

Challenges remain in determining which displaced supracondylar humerus fractures are safe to postpone surgical treatment until daylight hours. The purpose of this study is to determine which characteristics can be identified to guide the timing of treatment of supracondylar humerus fractures.

METHODS

225 completely displaced Gartland extension type 3/4 supracondylar humerus fractures in healthy patients that presented between 6 am and 7 am were identified. Data were collected retrospectively. Data analysis included univariate, multivariable logistic regression and classification and regression tree analysis.

RESULTS

5% (78/225) underwent surgical treatment the night they presented, while 65% (147/225) were treated the next day. Overall complication rate was 6%, with no difference based on timing of surgery. 12% (28/225) presented with a motor nerve injury, while 6% (14/225) a "pink pulseless" extremity. Statistical analysis found the most reliable radiographic predictor to be the maximum displacement on the anterior-posterior or lateral view. Classification and regression tree analysis developed a clinical algorithm; patients with a "pink pulseless" extremity or motor nerve injury were recommended for surgery overnight, while those with an anterior-posterior or lateral view < 25 mm were recommended for surgery the next day.

CONCLUSION

This study provides guidance on the timing of treatment for displaced supracondylar humerus fractures that present overnight. We provide a simple algorithm with three key clinical predictors for timing of treatment: presence of a "pink pulseless" arm, presence of a motor nerve injury, and displacement of any cortex by at least 25 mm (anterior-posterior or lateral view). This provides a step forward to help practitioners make safer evidenced-based timing decisions for their patients.

LEVEL OF EVIDENCE

Prognostic Study, Level II.

The trochlear physeal line angle: a novel method to assess coronal plane alignment of the paediatric distal humerus

Supracondylar humeral fractures account for 60% of elbow fractures in childhood, with cubitus varus being its most common complication. It can be avoided by accurate assessment of distal humeral alignment after fracture reduction, and the Baumann angle is the usual measurement for this purpose. However, several reports demonstrate an inconsistency of this angle, and our hypothesis is that reliability could be improved with angles drawn between the trochlear physeal line and the humeral longitudinal axis. The aim of the study was to compare intra- and interobserver reliability between the Baumann angle and angles drawn between the trochlear physeal line and (1) humeral longitudinal axis (X-angle), (2) humeral lateral cortex line (Y-angle), (3) humeral medial cortex line (Z-angle). Angle measurements were performed on 141 distal humerus' radiographs of children aged 3-10 years by five observers in a tertiary hospital. The measurements were compared for their intra- and interobserver agreement. All measurements showed good or excellent intraobserver agreement levels, with the highest for Z-angle [intraclass correlation coefficient (ICC) = 0.906] and the lowest for Baumann angle. There were also excellent interobserver agreement levels for all angles, the highest for Z-angle (ICC = 0.885). There are indications that Z-angle had higher agreement levels when compared to the others (ICC = 0.954; 0.936-0.969) in the group aged 7-10 years. The angle drawn between the humeral medial cortex and trochlear physeal line showed greater agreement than the other angles analysed, becoming a potentially useful tool for evaluation of children with supracondylar humeral fractures in daily practice.

O ângulo de Baumann: Uma análise da teoria à prática

Objetivo Analisar como o ângulo de Baumann (AB) é afetado por inclinações radiográficas inadequadas.

Métodos Estudo realizado a partir de radiografias do úmero distal de crianças de 3 a 10 anos. Foram comparadas as aferições do AB realizadas por cinco observadores, e cada radiografia foi avaliada quanto à sua qualidade em “adequada” ou “inadequada”. A correlação entre a qualidade radiográfica e a normalidade dos ângulos foi avaliada.

Resultados Amostra composta por 141 pacientes, 44% entre 3 e 6 anos e 56% entre 7 e 10. Observamos AB entre 52,01 e 89,82 graus, tendo cerca de 16% das medidas fora dos limites de normalidade da literatura. Um total de 33,3% das radiografias avaliadas foram classificadas como “inadequadas”. Sobre as medidas do AB fora do parâmetro da normalidade, observamos que sua proporção foi maior entre as imagens com qualidade radiográfica inadequada (31,1% vs. 6,2%), tendo essa diferença se mostrado significativa (p < 0,001).

Conclusões O AB é uma medida muito variável e, isoladamente, pouco confiável para a avaliação de deformidades angulares do cotovelo pediátrico, tendo a qualidade radiográfica se mostrado um fator causal importante dessa variabilidade.

Humerus trochlear angle (HTa)-a possible alternative for Baumann angle in the reduction of supracondylar humerus fractures

BACKGROUND

The supracondylar humerus fractures are the most common fracture in children's elbows. Generally, close reduction and percutaneous pinning can provide satisfactory outcomes after adequate reduction. Baumann angle is commonly used to evaluate reduction quality, however, it may fail to assess reduction well when the elbow is in flexion and/or when the patient is young. We conducted this study to evaluate the potential value of the humerus trochlear angle (HTa) for the reduction evaluation and compare it with the Baumann angle.

METHODS

We retrospectively reviewed supracondylar humerus fractures in our trauma center from 2016 to 2019. Patients were grouped as followed: in the HTa group, an arthrogram was used to evaluate the HTa angle and reduction (HTa, defined by the intersection of the axis of the humerus shaft and the tangent of the articular surface of the trochlear); In the Baumann group, the Baumann angle was used to assess the reduction. Baumann angle ratio (BA of injured side/BA of contralateral side) was calculated to evaluate the reduction quality between groups. Flynn's grading criteria were utilized to evaluate both function and cosmetic outcomes in two groups during the follow-up. Operation time, fluoroscopy shots, complications and Flynn's grading scores were compared between groups.

RESULTS

A total of 57 patients with an average age of 4.62 years and follow-up duration of 21.49 ± 5.40 months were included in the analysis. The gender and age distributions were similar in the two groups. Fluoroscopy shots in the HTa group were significantly less than in Baumann group (16.17 ± 0.73 vs. 21.85 ± 0.78, p < 0.0001), and operation time were also less in HTa group (45.78 ± 1.96 min vs. 62.21 ± 1.58 min, p < 0.0001). Baumann ratio showed no significant difference between the two groups (1.002 ± 0.023 in the Baumann group and 1.01 ± 0.023 in HTa group, p < 0.0001). Length of hospitalization, complications, and Flynn's grading scores were similar between groups. The HTa angle was positively correlated with Baumann angle in the HTa group (R-value is 0.71 and P = 0.0002).

CONCLUSIONS

There was no significant difference in reduction quality and Flynn's scores between HTa and Baumann groups. Furthermore, HTa was associated with shorter operation time and less radiation exposure in this investigation. Therefore, HTa may be a convenient and reliable parameter that could guide the reduction of supracondylar humerus fractures, especially for young children.