The rotation of the humeral head does not alter radiographic evaluation of the head-shaft angle

BACKGROUND

The head-shaft angle is used to plan osteotomies and arthroplasties and to assess the radiographic outcomes of surgical treatment for proximal humerus fractures. There are no published data showing whether different degrees of arm rotation interfere with the evaluation of this angle.

METHODS

Eighteen humeri from adult cadavers were used. Radiographs were taken with the specimens initially placed in a true anteroposterior position and then subsequently positioned with internal and external rotations of 10°, 20°, and 30°. All radiographs were evaluated by 3 shoulder and elbow surgeons at 2 different times 3 months apart. The head-shaft angle was measured using a picture archiving and communication system.

RESULTS

For the humerus in the neutral position, the head-shaft angle was 137° ± 4°. With the anatomic specimen positioned with increasing external and internal rotations, there was a maximum difference of 2° compared with the value observed in the neutral position, which was not a significant difference (P = .911). Measurements of the head-shaft angle showed a good interobserver correlation coefficient, with a value of 0.788 (0.728-0.839) for all measurements. The intraobserver correlation coefficient ranged from moderate to excellent (0.536-0.938).

CONCLUSION

The head-shaft angle did not change significantly with varying degrees of humeral rotation. The interobserver correlation coefficient showed good reliability, and the intraobserver correlation was moderate to excellent.

Morphologic features of humeral head and glenoid version in the normal glenohumeral joint

BACKGROUND

The morphologic features and clinical significance of version of the humeral head and glenoid remain unclear. The purpose of this study was to evaluate the normal values of humeral head version and glenoid version on computed tomography scans and to clarify their features in the normal glenohumeral joint.

METHODS

Images for analysis were computed tomography scans of 410 normal shoulders from healthy volunteers. Values of humeral head and glenoid version were measured. In glenoid version measurement, 3-dimensionally corrected slices were reconstructed to eliminate scapular inclination. Differences in humeral head version and glenoid version were assessed between dominant and nondominant shoulders and between men and women. Correlation analyses were also performed in the values of version between dominant and nondominant shoulders and between humeral head version and glenoid version.

RESULTS

The values of humeral head retroversion were widely distributed from -2° to 60°, with an average of 26° ± 11°. Average glenoid retroversion was 1° ± 3°, ranging from -9° to 13°. Both humeral head retroversion and glenoid retroversion were significantly higher on the dominant side than on the nondominant side and significantly higher in men than in women. Humeral head version and glenoid version values were well correlated with those of the contralateral shoulder. No correlation was found between humeral head version and glenoid version.

CONCLUSIONS

This study found differences in humeral head version and glenoid version by sex and shoulder dominance in a large sample. Both the humeral head and glenoid are thought to be more retroverted in high-demand shoulders.