A retrospective cephalometric study of patients who underwent reduction genioplasties showed large variations in soft-tissue response to osseous reduction. 2. The vertical and horizontal soft-tissue changes coincident to osseous reduction were less than expected. The maximum soft-tissue change observed was approximately 50 per cent that of the hard tissue removed. On the average, the vertical soft-tissue change was about 30 per cent and the horizontal was 25 per cent, when degloving procedures were combined with some form of ostectomy. 3. A considerable length of time is necessary before the soft-tissue changes are stable after reduction genioplasty. In some cases, significant changes occurred up to 8 to 10 months postoperatively. 4. A classification of macrogenia is proposed, based upon a more exact anatomic description of the deformity. 5. On the basis of this classification, the results of the present study, and more recent clinical results, recommendations for the surgical treatment of macrogenia are made.
