Objective: To measure the anatomic data of the proximal femur and to design an internal fixation instrument aiming at subtrochanteric fracture.
Methods: We measured the anatomic data of 56 pairs of the matching proximal femur specimens: the diameter of femoral head (HD), the axis length of femoral head (HAL), 135 degree femoral head-neck axis length (HNAL), 135 degree femoral head-neck axis upper length (HNAUL), 135 degree femoral head-neck axis underside length (HNADL), the anterior-posterior axis diameter of femoral neck (NAPD), the upper-underside diameter of femoral neck (NUUD), femoral neck-shaft angle (NFA), femoral shaft lateral cortex-greater trochanter angle (SLGA), the medial-lateral diameter of lesser trochanter level's femoral shaft (LSMLD), the anterior-posterior diameter of lesser trochanter level's femoral shaft (LSAPD), the medial-lateral diameter of 5 cm below lesser trochanter femoral shaft (5 cm MLD), and the anterior-posterior diameter of 5 cm below lesser trochanter femoral shaft (5 cm APD). Part of the data was analyzed and compared.
Results: HD was (46.69+/-3.73) mm, HAL was (39.22+/-4.17) mm, HNAL was (95.45+/-8.16) mm, HNAUL was (84.02+/-7.11) mm, HNADL was (99.95+/-9.34) mm, NAPD was (26.27+/-3.15) mm, NUUD was (32.24+/-3.31) mm, NFA was 126.21 degree+/-7.13 degree, SLGA was 16.38 degree+/-4.04 degree, LSMLD was (31.05+/-3.57) mm, LSAPD was (27.63+/-2.96) mm, 5 cm MLD was (26.36+/-3.22) mm, and 5 cm APD was (25.59+/-2.75) mm. NFA was positively correlated with SLGA (r=0.396, P=0.003).
Conclusion: It is necessary to design internal fixator to fit the anatomical feature of Chinese femur for the treatment of subtrochanteric fracture, and we should thoroughly consider the angle of the SLGA.