Role of computed tomography in glenohumeral joint deformity following obstetric brachial plexus injury: Proposed radiological classification

Abstract

Objective: The study aimed to study the usefulness of computed tomography (CT) in the measurement of glenoid version angle, humeral head dislocation, or subluxation and to propose a grading system for the severity of glenohumeral deformity following OBPI. Material and Methods: A prospective study conducted over a period of 3 years. The study group includes 21 children below the age of 12 years presenting with posterior dislocation of the shoulder, with prior history of OBPI. CT of both shoulders was done using a 128-slice CT scanner. The children were assessed clinically by a Modified Mallet Scale and graded by Waters classification. Results: We graded the severity of deformity on the affected side according to Waters et al. The difference between affected and normal shoulder glenoscapular angle (GSA), percentage of humeral head anterior to the scapular line (PHH), scapular height, and scapular width was statistically significant (P < 0.05). We propose grading for severity and assessed joint stability based on the CT parameters. GSA and PHH show a statistically significant difference between the three grades (P < 0.05). We also confirm that the higher the grade of the deformity, the more difficult the shoulder movements leading to worse scores on the Modified Mallet Scale. Conclusion: CT scan identifies glenohumeral deformities such as increased glenoid retroversion, posterior dislocation of the humeral head, smaller humeral head size, and smaller size of the scapula as deviations from normal status and helps in radiological grading.