Evaluation of the age and gender related changes in the Blumensaat line

Purpose The position of the patella according to the femur is very important in the evaluation of patella-femoral joint disorders. In 1938, Blumensaat (BS) described the BS line to evaluate the patella femoral congruence. This method is still valuable in clinical use. There is a limited number of studies demonstrating the accuracy of BS method as well as the affected variables. The aim of this study was to evaluate o the age and gender-related changes in the BS line. Methods Standard lateral knee radiography was performed to all patients at 30° flexion. The relationship between the BS line and the patella inferior pole was examined and the variability of the measurements according to gender and age groups was investigated by statistical methods. Results Ninety-five patients (43 men and 52 women) were enrolled in the study. Mean age of the patients were 43.7 ± 14.1 years (48.2 ± 11.7, 37.9 ± 14.8 in women and men, respectively). The BS line was passed through the inferior pole of the patella in only 2 (2.1%) of 95 patients. There was a statistically significant difference ( p = 0.041) between BS measurement and gender which was found to be higher in females than males. There was no statistically significant correlation with this distance between the age groups ( r = − 0.216, p = 0.427). Conclusion In our study, it was concluded that BS measurement differs according to gender but did not have any difference between different age groups.