動揺性肩関節症における肩甲骨と肩甲上腕関節の動作解析―レントゲン計測とOpen MRIを用いた解析―

抄録

The slipping phenomenon which is the rentogenographic features and means the non-centripetal relationship in the gleno-humeral joint, especially seen in loose shoulder (LS) patients. Though the abnormal kinematics of the scapula is admitted, there are few quantitative evaluations. The evaluated subjects of the scapular motion consisted of 80 each LS and normal volunteers, using the roentgenograms and for that of the gleno-humeral joint consisted of 7 LS patients and 6 normal volunteers, using the open MRI. Analysis of the scapular motion: the lateral rotated angle was measured of the elevated position. Analysis of the gleno-humeral joint: MR images were extracted at 30 and 135 degrees elevated positions. The description of the bony frame by digitizing using the software was developed from the obtained- images.3D reconstruction images were performed. The reconstructed humeral head was assumed to be a sphere and the position of the center was calculated in the 3D coordinates. The plane formed by the edges of the glenoid was assumed to be the glenoidal plane and the origin of the plane was set. The center of the head was projected to the glenoidal plane and the relationship between its position and the origin was evaluated. The results showed that the translation of the humeral head was small at 30 degrees elevated position in both groups. In the 135 degrees elevated position, the position of the humeral head was located posteriorly and inferiorly in the LS group rather than that of the normal shoulder. The lateral rotation of the scapula tended to be small in the LS group. In conclusion, it is important for the consideration of instability of the shoulder joint to evaluate the kinematics of both the gleno-humeral joint and the scapula, though conventionally it was mainly focused to the movement of the gleno-humeral joint.