Intercondylar shelf angle in adult black Malawian subjects

In this study, we determined the intercondylar shelf angle of the femur in adult black Malawian subjects as measured in lateral radiographs of the knee joint. A total of 856 radiographs were used: 464 from men and 392 from women, aged 18-70 years. A goniometer measured the intercondylar shelf angle at the intersection between Blumensaat's line and a line drawn along the edge of the distal third of the femur parallel to the posterior cortex of the bone. The mean intercondylar shelf angle of 136.60 degrees +/- 5.90 degrees in Malawians of both sexes was significantly different from 142.57 degrees +/- 5.86 degrees for American subjects (P < 0.001), as given by Craig (1995, J. Forensic Sci. 40:777-782), but the level of statistical significance between black Malawian females and black American females was at P < 0.01. Using the intercondylar shelf angle, 66.67% of male Malawians were correctly identified as such and 50.00% of Malawians females as such. Eighty-three percent of males and 81.30% of females were correctly identified as blacks. This angle has been shown to exhibit sexual dimorphism in Malawian subjects. Its importance in forensic anthropology is stressed.