[Purpose] We investigated the utility of MR imaging of the shoulders in abduction and external rotation position (ABER method) for evaluating the anterior inferior glenohumeral ligament (AIGHL).
[Materials and methods] Nineteen shoulders of 19 patients (age ranged from 17 to 49 years old, average 28 years old) with traumatic anterior glenohumeral instability were examined. Seven shoulders were first dislocations and 12 shoulders were recurrent anterior dislocations. T2*-weighted images with 3D-FT technique (2mm continuous slices) were obtained in the ABER position with superconducting MR imager (1.5 tesla). According to the MR images obtained in the ABER position, the shoulders were classified into two groups: Group A with a well delineated anterior capsule, and Group B without one. Arthroscopically, the shoulders with a thick and wide AIGHL were regarded as AIGHL(+)and those with a thin or no AIGHL as AIGHL(-). We compared the classification on the MR images with arthroscopic conditions of the AIGHL.
[Results] Eight out of 9 Group A shoulders were AIGHL(+), and nine out of 10 shoulders of Group B were AIGHL(-). The sensitivity and specificity of MRI evaluation were 89% (eight of nine shoulders)and 90% (nine of 10 shoulders) for prediction of the AIGHL condition. There were significant differences between Groups A and B.
[Conclusion] MR imaging with the ABER method was useful for evaluating the condition of the AIGHL.
