Capsular elongation in shoulders with recurrent anterior dislocation. Quantitative assessment with magnetic resonance arthrography.
BACKGROUND
Elongation of the shoulder capsule is often noticed on arthrograms or during surgery in shoulders of patients who have experienced recurrent anterior dislocations.


OBJECTIVE
We can quantify the elongation of the capsule in shoulders with recurrent anterior dislocations by using magnetic resonance arthrography.


METHODS
Retrospective review of prospectively collected data.


METHODS
Twelve patients with unilateral recurrent anterior shoulder dislocations were enrolled in this study. Magnetic resonance images in the axial and coronal oblique planes were obtained from both shoulders (involved and uninvolved sides) after 10 ml of gadolinium/saline solution was injected into the glenohumeral joint. The length of the anteroinferior, inferior, and posteroinferior portions of the capsule was measured by using image analyzing software and normalized to the humeral head diameter.


RESULTS
The anteroinferior capsule was significantly elongated in the involved shoulder at 4 mm (16% elongation) and 10 mm (19% elongation) superior to the inferior margin of the glenoid. The inferior capsule was also significantly elongated in the involved side both at the center (12% elongation) and at 4 mm anterior to the center of the glenoid (29% elongation). The posteroinferior capsule did not show any significant elongation.


CONCLUSIONS
The anteroinferior and inferior portions of the shoulder capsule are elongated an average of 19% in shoulders with recurrent anterior dislocation.
Urayama
Masakazu
M
Department of Orthopedic Surgery, Akita University School of Medicine, Hondo, Akita, Japan.
Itoi
Eiji
E
Sashi
Ryuji
R
Minagawa
Hiroshi
H
Sato
Kozo
K
D000293:Adolescent; D000328:Adult; D001175:Arthrography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D017746:Joint Capsule / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012783:Shoulder Dislocation / Q000473:pathology*
D003287:Contrast Media; D019786:Gadolinium DTPA