ISAKOS Congress 2021

2021 ISAKOS Biennial Congress Paper

 

Differences in Glenohumeral Joint Capsule Dimensions on MR Analysis in Adolescent Patients with MDI and Bankart Tear

Mason Cole Yoder, BS, Cincinnati, OH UNITED STATES
Colin McDonald, MD, York, Pennsylvania UNITED STATES
Shital N. Parikh, MD, Cincinnati, OH UNITED STATES

Cincinnati Children's Hospital and Medical Center, Cincinnati, OH, UNITED STATES

FDA Status Not Applicable

Summary

The purpose of this study was to identify objective criteria for MDI diagnosis based on glenohumeral capsular dimensions and compare it to those with traumatic Bankart tears.

Abstract

Purpose

Multidirectional Instability (MDI) of shoulder in adolescents is a clinical diagnosis and there are no defined objective criteria to validate the diagnosis. Most patients with MDI have no identifiable labral or capsular tear pattern on MR imaging. In contrast, patients with Bankart tear usually have a definitive history of dislocation, positive clinical findings and typical capsulolabral tear pattern. The purpose of this study was to identify objective criteria for MDI diagnosis based on glenohumeral capsular dimensions and compare it to those with traumatic Bankart tears.

Methods

In a comparative retrospective study, the clinical records and MR arthrograms of adolescent patients treated for shoulder instability at our center between 2008 and 2019 were reviewed. 24 patients diagnosed and treated for MDI were age-matched to 25 patients diagnosed and treated for Bankart tears. The width and depth of the rotator interval and linear dimensions of the glenohumeral capsule in multiple directions were measured on MR arthrography. These dimensions were compared between the 2 groups using a Student’s t-test.

Results

24 patients (33 shoulders) 20 females, 4 males were in the MDI group; average age at time of surgery was 15.2 years (range, 8-20 yrs). The Bankart group consisted of 25 patients (28 shoulders), 9 females, 16 males; average age at time of surgery was 15.5 years (range, 11-19 yrs). The rotator interval depth was significantly greater in the MDI group than the Bankart group (MDI 8.5mm; Bankart 6.1mm) (p <0.01). Similarly, the inferior, posteroinferior, and posterior dimensions of the glenohumeral joint capsule were significantly greater in the MDI group (inferior 24.5mm; posteroinferior 26.4mm, posterior 22.5mm) than in the Bankart group (inferior 20.4mm, posteroinferior 21.9mm, posterior 19.3mm) (p <0.01). Rotator interval width and all other capsular dimensions showed no statistically significant difference between the 2 groups.

Conclusion

This study concluded that depth of the rotator interval and dimension of the glenohumeral joint capsule in the inferior, posterior, and posteroinferior direction on MR arthrography were significantly greater in adolescent patients with MDI as compared to patients with Bankart tears. This information needs to be further validated in prospective fashion and compared to normal capsular dimensions to calculate cut-off values for MDI diagnosis on MR analysis.

Significance

Measurement of glenohumeral capsular dimensions on MR arthrography can be used to supplement clinical diagnosis of MDI.

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