MRA Findings, Arthroscopic Findings, and Glenohumeral Joint Instability of Initial Traumatic Anterior Dislocation of the Shoulder.

Abstract

The treatment of initial traumatic anterior dislocation of the shoulder has not been established. We, orthopaedists, are eager to know whether it is possible to predict the prognosis of an initial dislocated shoulder or not. The purpose of this study was to clarify the characteristic findings of MR arthrography (MRA) and intraarticular lesions indicating instability in a first-time dislocated shoulder.
Ten patients (9 males and 1 female) who sustained initial traumatic anterior dislocations of the shoulder underwent arthroscopy. The average age was 25.8 years old (range: 20 to 39 years). We investigated the correlation the between the results of the examination under anesthesia (EUA) and MRA findings and intraarticular lesions by arthroscopy. The MRA findings were classified using the Hirose's system and the intraarticular lasions were classified using Baker's arthroscopic criteria.
Two shoulders were stable on EUA. They had negative Bankart lesions using Hirose's MRA classification. Their anthroscopic findings were no labral lesion and a partial labral lesion, which corresponded with Baker's group I and group II. The other 8 shoulders had unstable EUA. They had positive Bankart lesions under Hirose's MRA classification. In 7 of the 8, labral disruptions and detachment of the IGHLs appeared under arthroscopy, and these findings corresponded with Baker's group III.
Thus, we found that preoperative MRA findings by Hirose's classification and arthroscopic findings based on Baker's criteria were essential factors to predict the fate of an initial dislocated shoulder.