CT ANALYSIS IN SHOULDER INSTABILITY

抄録

228 shoulders were divided into the following three groups according to the shoulder instability. GroupI: Suffered from loose shoulder syndrome, which had instability induced by downward traction in both internally and externally rotated position, antero-posterior instability of the humeral head and outward slipping of the humerus in the elevated position(66 joints 41cases). GroupII: Had downward instability in the internally rotated position but they were stable in the externally rotated position(57 joints 52 cases). GroupIII: Were stable in any position(105 joints 99 cases). CT scans were investigated by the following method. A line was drawn from the anterior angle of the glenoid(A) to the posterior angle(B). Then a vertical line was drawn from B to line A-B. The point of intersection of this vertical line and the humeral head was described as C. The angle CAB was named posterior opening angle of the glenohumeral joint(POA).
In GroupI it was 23.1±0.7 degrees(mean±standard error). In GroupII it was 16.8±0.5 degrees. In GroupIII it was 12.0±0.3degrees. The application of a “t” test yielded a P value of less than 0.01 for the difference between each group.