A Application Study On The Anatomical Landmarks Of Tibial Tubercle In The Selection Of The Entry Point Of Tibial Intramedullary Nail

Objective:By taking standard full-length X-ray films of the lower limbs from the positive and lateral position for patients and volunteers,measuring the vertical distance from the peak of the tibial tubercle to tibia axis on the X-ray films and determining the relationship when the best entry point of tibial intramedullary nail for Chinese is in the coronal and the peak of the tibial tubercle,this paper attempts to find a simple and accurate method to determine the correct entry point and to provide reference for the selection of the entry point of intramedullary nail in the treatment of tibial shaft fracture.Methods:Take standard full-length shank X-ray films from the positive and lateral position(ankles and knees included)for 40 volunteers and outpatients of the traumatic orthopedics department of the Affiliated Hospital of Yan’an University from November 2015 to October 2016.When taking the X-ray films,the knee shall be as straight as possible,the lower limbs shall be at the neutral position,the patella be vertically upward and the highest point of the tibial tubercle be marked on the skin and put a metal ball of 3mm in diameter.After the X-ray film is taken,take the center of the small dot on the X-ray film as the projection of the peak of the tibial tubercle on the X-ray film and draw out the tibial axis X-ray film,then measure the vertical distance from the tibial tubercle to the tibial axis and calculate its 95% confidence intervals.After the 80 lower limbs are grouped by gender and side respectively,compare the measuring results and take the T-test with two independent samples.Results:1.Among the tibial tubercle surface projection of 80 lower limbs,74 are located at the outside of the tibia axis,6 in the inside of which 4 are men’s,2 are right legs,2 left legs,2 women’s,1 right leg and 1 left leg.The vertical distance between the tibial tubercle and tibia axis is(3.27±0.32)mm and the 95% confidence intervals(3.20 mm,3.34mm).2.When grouped by gender,the vertical distance between the tibial tubercle and tibia axis in male group is(3.28±0.32)mm while in female group the number is(3.27±0.32)mm.The comparative result of the vertical distances of the two groups has no statistical significant(P =0.861 > 0.05).3.When grouped by side,the vertical distance between the tibial tubercle and tibia axis in the left-side group is(3.26±0.28)mm while in the right-side group the number is(3.32±0.35)mm.The comparative result of the vertical distances of the two groups has no statistical significant(P=0.394 > 0.05).Conclusion:The tibial tubercle is the easiest anatomic landmark to be recognized on the proximal tibia.It is simple and reliable to determine the entry point of tibial intramedullary nail through tibial tubercle.Experimental study shows that when the tibial axis is located at(3.27 + 0.32)mm of the inside or outside of the tibial tubercle,it is the best entry point,mostly the inside,but factors as gender,side has no obvious effect on the results.Compared to foreign studies which show that the tibial axis in the coronal plane is located at 0.5-1.0 cm of the tibial tuberosity,the tibial axis of Chinese in the sagittal plane is closer to the midpoint of the tibial tubercle.