Jung-Taek Kim1, Chang-Ho Jung2, Quan Hu Shen3, Yong-Han Cha4, Chan Ho Park5, Jun-Il Yoo6, Hyung Keun Song1, Yongho Jeon2, Ye-Yeon Won7. 1. Department of Orthopaedic Surgery, Ajou University School of Medicine, Ajou Medical Center, Suwon, South Korea. 2. Department of Mechanical Engineering, Ajou University, Suwon, South Korea. 3. Department of Orthopaedic Surgery, Ajou University School of Medicine, Ajou Medical Center, Suwon, South Korea; Department of Orthopaedics, First People's Hospital of Suqian City, Jiangsu, China. 4. Department of Orthopaedic Surgery, Eulji University Hospital, Daejeon, South Korea. 5. Department of Orthopaedic Surgery, Yeungnam University Medical Center, Daegu, South Korea. 6. Department of Orthopaedic Surgery, Gyeongsang National University Hospital, Jinju, South Korea. 7. Department of Orthopaedic Surgery, Ajou University School of Medicine, Ajou Medical Center, Suwon, South Korea. Electronic address: thrtkr@ajou.ac.kr.
Abstract
BACKGROUND/ OBJECTIVE: The choice of implant is one of the most easily controllable factors affecting the outcome of intertrochanteric fractures. While most of the caput-collum-diaphysis (CCD) angles of the femur are within the range of 125° and 130°, there is a shortage of data on whether 125° or 130° implants are preferable. Thus, the present finite element analysis (FEA) aimed to compare the biomechanical effects on the fracture surface when using implants with different CCD angles where the anatomical CCD angle of the femur was between 125° and 130°. METHODS: After establishing a finite element model of an unstable intertrochanteric fracture from the femur with a native CCD angle of 127.3°, proximal femoral nail antirotation (PFNA) models with CCD angles of 125° and 130° were virtually implanted to have the same position of screw tip, respectively. RESULTS: In the one-leg stance during walking, when the implant with 130º CCD angle was used, the magnitude of compressive stress (1.61 and 2.12 MPa in the 130° and 125° model, respectively) was lower and the area of the fracture surface under tensile stress (55% and 5% in 130° and 125° model, respectively), the interfragmentary movements (40.9% more movement in 130° model), and the magnitude of bone deformation (23.5% more deformation in 130° model) were more than those of the 125° model. CONCLUSION: The intertrochanteric fracture fixed with PFNA with a 125º CCD angle revealed less interfragmentary movement on the fracture surface when the native CCD was an in-between angle in the FEA.
BACKGROUND/ OBJECTIVE: The choice of implant is one of the most easily controllable factors affecting the outcome of intertrochanteric fractures. While most of the caput-collum-diaphysis (CCD) angles of the femur are within the range of 125° and 130°, there is a shortage of data on whether 125° or 130° implants are preferable. Thus, the present finite element analysis (FEA) aimed to compare the biomechanical effects on the fracture surface when using implants with different CCD angles where the anatomical CCD angle of the femur was between 125° and 130°. METHODS: After establishing a finite element model of an unstable intertrochanteric fracture from the femur with a native CCD angle of 127.3°, proximal femoral nail antirotation (PFNA) models with CCD angles of 125° and 130° were virtually implanted to have the same position of screw tip, respectively. RESULTS: In the one-leg stance during walking, when the implant with 130º CCD angle was used, the magnitude of compressive stress (1.61 and 2.12 MPa in the 130° and 125° model, respectively) was lower and the area of the fracture surface under tensile stress (55% and 5% in 130° and 125° model, respectively), the interfragmentary movements (40.9% more movement in 130° model), and the magnitude of bone deformation (23.5% more deformation in 130° model) were more than those of the 125° model. CONCLUSION: The intertrochanteric fracture fixed with PFNA with a 125º CCD angle revealed less interfragmentary movement on the fracture surface when the native CCD was an in-between angle in the FEA.