Anatomical Measurement of Normal Korean Proximal Femur Using Plain Radiography: A Problem when using Proximal Femoral Nail Anti-rotation

ABSTRACT

PURPOSE: We propose to improve the use of Proximal Femoral Nail Anti-rotation in Korea by reporting anatomical measurements of the normal Korean proximal femur. MATERIALS AND METHODS: A total of 230 patients were enrolled who had all experienced a femoral intertrochanteric fracture and undergone the Proximal Femoral Nail Anti-rotation surgical procedure between February 2007 and April 2011. We measured the neck-shaft angle and endosteal width at the isthmus of a normal femur, and the distance between the greater trochanter and the nail tip of the Proximal Femoral Nail Anti-rotation in post-operative plain radiography. We analyzed the average and standard deviations of the measurements. We also investigated correlations with the patient gender. RESULTS: The average neck-shaft angle and endosteal width at the isthmus were 129.7degrees(111.0~138.3degrees) and 14.5 mm (9.7~23.1 mm), respectively. The average protruded nail length was 4.9 mm (1.0~15.0 mm). The femur neck-shaft angle had a correlation ratio with gender (p=0.000). However, the endosteal width at the isthmus level and the protruded nail length had no correlation ratio with gender (p=0.108, 0.573, respectively). CONCLUSION: Until now, in intertrochanteric fracture operations using Proximal Femoral Nail Anti-rotation, the selection of devices has been extremely limited. Through this study we present the average Korean anatomical neck-shaft angle, endosteal width of the femur, and protruding length of the nail tip. We expect that these numerical values can be used in the production of new devices with shorter proximal nails, which would be more appropriates for Koreans.