[Computerized tomography measurement of anteroposterior humeral dislocation. Proposing a method. Application to centered osteoarthritis].

PURPOSE OF THE STUDY

The authors proposed a CT method to measure the humeral head subluxation in sagittal plane. They used this method to analysed the sagittal position of the humeral head, in primary gleno humeral osteoarthritis without humeral head elevation.

MATERIAL AND METHODS

The control group was composed of 50 shoulder computed tomography in small rotator cuff tear confined to the supraspinatus muscle (Bernageau stade I on the arthrography). We evalued computer tomographic findings in 104 cases of primary gleno humeral osteoarthritis without humeral head elevation. The results were expressed in rate of subluxation.

RESULTS

This method can be used to measure sagittal subluxation of the humeral head in scapulo humeral pathology. In 35 per cent of cases, gleno humeral osteoarthritis without humeral head elevation, the posterior subluxation (rate of subluxation > 55 per cent) can explain the arthritic evolution. If total shoulder arthroplasty is performed, persistent posterior subluxation may result in premature posterior wear of the glenoïd component, or, in premature loosening of the glenoïd component.

CONCLUSION

The method used for sagittal subluxation of the humeral head measurement is precise. This study, emphasizes the pronostic interest and the therapeutic consequences of this measurement in gleno humeral osteoarthritis without humeral head elevation.