抄録
[Purpose]
There have been the no reports on the correlation between loose shoulder and hypoplasia of the acromion. Morphological appearances and hypoplasia of the acromion were evaluated using the cineradiogram findings.
[Subjects]
The following subjects were reviewed; 120 loose shoulders (group LS) and 120 normal volunteer shoulders (group N).
[Methods]
Cineradiography was recorded on a video system and the morphological appearances were classified into three types. Type I is the shape in which the lateral edge of the acromion shows a beak edge and an undeveloped angle. Type II is the shape in which the angle is roundish. Type III is the shape in which the lateral edge is flat and the angle is broad.
Clear images were also analyzed. The following measurements were evaluated:
1) the maximum transverse diameter of the acromion
2) the angle between the line under the acromion and the line of the glenoid articular surface (Acromion angle)
3) the angle between the line from the lateral acromion edge to the center of the humeral head and the line of the glenoid articular surface (Acromion Edge angle)
4) the location of the lateral acromion edge
[Results]
The morphorgical appearances, in group LS, Type I, Type II and Type III were 27.5%,36.7% and 35.8%, respectively. Whereas in group N, Type I, Type II and Type III were 10.8%,29.2% and 60.0%, respectively.
There were significant differences between group LS and group N in the transverse diameters, acromion angles and acromion edge angles. The position of the lateral acromion edge tended to be located in the medial-superior site in group LS.
[Conclusion]
A beak edge and hypoplasia of the acromion were found in looses houlders.
