An interpopulation comparison of 3-dimensional morphometric measurements of the proximal humerus.

Background: Precise anatomic reconstruction of the proximal humerus is essential to a favorable outcome of total shoulder arthroplasty. Because of the wide variation in the geometric features of the proximal humerus, prosthetic designs incorporating these disparities are being developed.

Methods: The aim of this study is to use data obtained from cadavers and computed tomographic scans to investigate the 3-dimensional morphometric parameters of the proximal humerus of South African and Swiss samples and make an interpopulation comparison. In addition, the study combines the interarticular variations between populations with the differences in sex and shoulder sides. With the aid of medical imaging techniques and engineering design tools, various geometric features were measured.

Results: The results obtained from these analyses revealed several differences in sex and shoulder sides. On average, the Swiss were larger in most of the measured parameters than the South Africans. The male shoulders of Swiss and South Africans were observed to significantly vary in 4 of the parameters measured. The South African male and female right shoulders varied considerably in one-fourth of the measured shoulder variables. Generally, for both populations, the left and right shoulders of the same individuals were not different in all the measured variables irrespective of sex.

Conclusion: The knowledge acquired in this study is expected to assist in the development of a population-specific shoulder prosthetic design and surgical planning procedures.