Size and morphology of the coracoid and glenoid in pediatric and adolescent patients: implications for Latarjet procedure.

Background: Glenohumeral instability is a challenging problem in children and adolescents. For patients with anterior glenoid bone loss, the Latarjet procedure is an effective treatment option. However, concerns about coracoid size and morphology may limit its utilization within this patient population. The purpose of this study was to establish normative data on coracoid and glenoid size and morphology among a large cohort of adolescent patients and describe the anatomic relationships with demographic factors. Methods: This is a retrospective cross-sectional study of a consecutive series of 584 patients aged 12-21 years after a chest computed tomography scan for non-shoulder related trauma at a single level I trauma center. Demographic characteristics were collected from the electronic medical record, and the following coracoid anatomic measurements were obtained from computed tomography scans: coracoid length, coracoid thickness, coracoid width, glenoid height, and glenoid width. The ratio of coracoid thickness to glenoid width was calculated to estimate the percent bone loss that could be addressed with a traditional Latarjet coracoid transfer. To ensure reliability among 3 reviewers, all measured the same 25 scans and inter-rater reliability was excellent with all Kappa coefficients >0.81. The remaining scans were divided equally and assessed separately by these reviewers. Correlation coefficients were used to quantify the relationships between all anatomic measures and the age, weight, and height of individuals. Growth curves for each measurement were modeled using quantile regression with height and height∗height as predictors. Additionally, we stratified the growth curves by sex, when significant. Of the 584 subjects, 55% were male, and average age was 19 years (range 12, 21). Results: All growth curves illustrated increase anatomic size across the height range of 145-190 cm. The growth curve including all patients (Fig. 1) illustrated that the 50% percentile of median coracoid length increased from approximately 28 to 32 mm. In addition to height, sex was a significant predictor for coracoid width and glenoid width. The median coracoid width increased from approximately 9.5 to 10.2 mm for females compared to an increased width from approximately 10 to 11 mm for males. The median glenoid width for females increased from approximately 21 to 25 mm and for males the median glenoid width increased from just under 22 to 25.5 mm. Conclusions: Among children and adolescents, coracoid and glenoid size are correlated with patient height. These data can help guide patient selection for the Latarjet procedure.