Valgus-related Elbow Pathology Is Not Associated With Decreased Baumann's Angle: A Case-control Study.

Abstract

Background: Previous studies have demonstrated that varus alignment of the elbow has been associated with lateral condyle fractures. However, for other pediatric and adolescent elbow pathologies, the influence of upper extremity alignment has not been investigated. This study aimed to compare elbow alignment (quantified using Baumann's angle) among patients with medial epicondyle humeral fractures and capitellum osteochondritis dissecans (OCD) and age- and sex-matched control patients.

Methods: Pediatric and adolescent patients (ages: 5-18 years, inclusive) treated at a tertiary care hospital for medial epicondyle fractures (MEFxs) and capitellum OCD lesions from January 2016 to October 2023 were retrospectively reviewed. Patients aged 5-18 years with anteroposterior elbow radiographs demonstrating no elbow pathology were included as controls. Patients were matched 1:1:1 based on sex and chronologic age within 2 years and placed into cohorts by injury. Baumann's angle was compared across groups using 1-way analysis of variance after data normality was established via Shapiro Wilk tests. Linear regression was used to assess whether fracture displacement in millimeters (in the MEFx group) or OCD lesion size (in the capitellum OCD group) correlated with Baumann's angle. A two-tailed significance threshold was set as P ​≤ ​.05.

Results: A total of 72 matched patients were included (24 MEFx, 24 OCD, and 24 controls). The mean age of the overall sample was 13.8 ​± ​1.9 years, with 79% being male. Mean Baumann's angle was 75.7 ​± ​5.9° in the MEFx group, 71.7 ​± ​7.9° in the OCD group, and 74.1 ​± ​5.2° in controls (P ​= ​.181). There was no association between fracture displacement and Baumann's angle in the MEFx group (P ​= ​.75), and there was no association between OCD lesion size and Baumann's angle in the OCD group (P ​= ​.31).

Conclusions: There was no difference in Baumann's angle among pediatric and adolescent patients with MEFx, capitellum OCD lesions, and age- and sex-matched controls. These findings suggest that static distal humerus alignment does not increase the risk for these injuries. Future studies should seek to evaluate dynamic alignment and its influence on these pathologies.

Key concepts: (1)Baumann's angle does not differ among pediatric and adolescent patients with medial epicondyle fractures (MEFxs), capitellum osteochondritis dissecans (OCD) lesions, and age- and sex-matched controls.(2)Static distal humerus alignment does not increase the risk for MEFxs or capitellum OCD lesions.(3)Future studies should evaluate the influence of dynamic alignment on these pathologies.

Level of evidence: III.