Abstract:

Objective To standardize the terminology related to the entry point and to explore the relationship between the proximal femoral bone markers and the surrounding soft tissues. Methods Previous publications about the suggested entry point for antegrade femoral nailing were reviewed and special attention was paid to “trochanteric fossa” and“piriform fossa”. The relationship between the trochanteric fossa but the greater trochanter in 130 Chinese adult dried femurs was analyzed. Twenty cadaveric lower limb specimens were dissected toobserve proximal femur soft tissue attachments and to measure data related with piriform muscle, internal and external obturator muscle. Results Firstly, the trochanteric fossa but not the piriform fossa was the standard entry point. Secondly, in 3.85% of the cases a shape with a free entry point was found, whereas 76.15% of the specimens were defined by a laterally projecting spine. In 20.00% cases the entry points was partially covered. Thirdly, the means of the vertical and horizontal widths of the piriformis tendon were (6.74±1.21)mm and(4.29±1.37)mm, respectively. The means of the vertical and horizontal widths of the obturator internus tendon were (6.36±1.74)mm and(5.74±1.61)mm, respectively. The means of the vertical and horizontal widths of the obturator external tendon were (6.26±1.13) mm and(4.57±1.26)mm, respectively. Fourthly, the mean distances of the anterior and posterior edges of the piriformis tendon attachment from the posterior limit of the greater trochanter, defined as a percentage of the anteroposterior length of the greater trochanter in this study, were(57.9±8.8)% and(43.8±8.7)%, respectively. Equivalent mean distances for the obturator internus attachment were (65.6±7.3)%and (52.6±6.9)%, respectively. Conclusion Piriform fossa should be named as Trochanteric fossa. Because of the various relationships between the trochanteric fossa and the greater trochanter, the entry point is variable, and the trochanteric fossa can not be considered as a general entry point. Quantitative data about tendons is helpful to optimize surgical approaches.

Key words: Intramedullary femoral nailing, Short external rotator, Trochanteric fossa, Proximal femur, Anatomical measurement, Adult