The Analysis of Biomechanical Properties of Proximal Femur after Implant Removal.
Introduction. To compare the biomechanical stability of the femur following the removal of proximal femoral nail antirotation (PFNA-II) and dynamic hip screw (DHS). Material and Methods. 56 paired cadaveric femurs were used as experimental and control groups. In the experimental group, PFNA-II and DHS were randomly inserted into femurs on both sides and then removed. Thereafter, compression load was applied until fracture occurred; biomechanical stability of the femurs and associated fracture patterns were studied. Results. The ultimate load and stiffness of the control group were 6227.8 ± 1694.1 N and 990.5 ± 99.8 N/mm, respectively. These were significantly higher than experimental group (p = 0.014, <0.001) following the removal of PFNA-II (4085.6 ± 1628.03 N and 656.3 ± 155.3 N/mm) and DHS (4001.9 ± 1588.3 N and 656.3 ± 155.3 N/mm). No statistical differences in these values were found between the 2 device groups (p = 0.84, 0.71), regardless of age groups. However, fracture patterns were different between two devices, intertrochanteric and subtrochanteric fractures. Conclusions. Mechanical stability of the proximal femurs does not differ after the removal of 2 different of fixation devices regardless of the age. However, it was significantly lower compared to an intact femur. Different fracture patterns have been shown following the removal of different fixation devices as there are variations in the site of stress risers for individual implants.
Scoliosis Research Institute, Department of Orthopedics, Korea University Medical College, Guro Hospital, Guro 2-dong, Guro-gu, Seoul 152-703, Republic of Korea.
Jae Hyuk
JH
Yang
Osong Medical Innovation Foundation, Medical Device Development Center, Cheongju 363-951, Republic of Korea.
Tae Gon
TG
Jung
Scoliosis Research Institute, Department of Orthopedics, Korea University Medical College, Guro Hospital, Guro 2-dong, Guro-gu, Seoul 152-703, Republic of Korea.
Arjun Rupanagudi
AR
Honnurappa
The Division of Biological Sciences at The University of Chicago, Undergraduate Class of 2014, 5801 South Ellis Avenue Chicago, IL 60637, USA.
Jae Min
JM
Cha
Scoliosis Research Institute, Department of Orthopedics, Korea University Medical College, Guro Hospital, Guro 2-dong, Guro-gu, Seoul 152-703, Republic of Korea.
Chang Hwa
CH
Ham
Jung-Hwa Girls High School, San 105 Beomeo-4-dong Sunsung-gu, Daegu 706-819, Republic of Korea.
Tae Yoon
TY
Kim
Scoliosis Research Institute, Department of Orthopedics, Korea University Medical College, Guro Hospital, Guro 2-dong, Guro-gu, Seoul 152-703, Republic of Korea.
Seung Woo
0000-0002-1536-4611
SW
Suh