Biomechanical research of a new proximal femoral nail antirotation in the process of intertrochanteric fracture healing / 医用生物力学

Objective To test the mechanical properties such as stiffness and strength of a new proximal femoral nail antirotation (PFNA) with three-dimensional finite element method and analyze its stress and strain distributions before and after the femur intertrochanteric fracture healing. Methods The three-dimensional model of PFNA was established by UG NX and the CT images were preprocessed by MIMICS. The finite element model of intertrochanteric fracture and fracture healing were developed for numerical simulation. Results Before the fracture healing, the maximal Von Mises stress was up to 663 Mpa at the location of fracture and that near the locking bolt was only 113 MPa after PFNA implanted. After the fracture healing, the maximal Von Mises stress occurred at the blade-nail interface. Obvious stress concentrations appeared near the locking bolt on the femur shaft. Conclusions The PFNA should be taken out because the femur shaft fracture often occurred at the location of the locking bolt after healing.

The PFNA Nail for Pertrochanteric Fracture of the Femur without Fracture Table

PURPOSE: The purpose of this study is to analyze the results of intertrochanteric fractures treatment with proximal femoral nail antirotation (PFNA) without using fracture tables and thereby prevent complications. MATERIALS AND METHODS: Forty cases of intertrochanteric fracture of 39 patients that were treated with PFNA without using fracture tables between January 2008 to December 2009 were analyzed. There were 13 males and 27 females. The mean age was 76 years old. Using AO classification, 6 cases were A1, 25 cases were A2 and 9 cases were A3. The operation was done without using fracture tables at supine position. Operation time, intraoperative bleeding were checked. For the result, Cleveland index, tip apex distance, fracture site sliding rate, change of femur neck and shaft angle were evaluated. Bone union time and complications were also estimated from the follow up radiograph. Statistics were analyzed using Independent T-test. RESULTS: The mean operation time was 40 minutes (25 to 70 minutes) and mean intraoperative bleeding was 113 cc (40 to 250 cc). The Cleveland index was shown 94% of 5, 6, 8 and 9 zone, the tip apex distance was 12.96 mm (6 to 22 mm), the fracture sliding distance was 1.9 mm (0 to 6 mm), the change of femur neck and shaft angle was 2.5 degree (0~10 degree) and the average bone union time was 15 weeks (8 to 24 weeks). The complication include 2 cases of delayed union and 2 cases of varus deformities. CONCLUSION: We have shortened the operation time by closed reduction methods without using the fracture tables, and the complication were minimized with using simple tools like a reduction forcep or bone hook at PFNA blade insertion.

Results of Treating Senile Osteoporotic Peritrochanteric Fracture with Proximal Femoral Nail Antirotation (PFNA)

PURPOSE: The purpose of this study was to evaluate the results of treating senile osteoporotic peritrochanteric fracture with proximal femoral nail antirotation (PFNA). MATERIALS AND METHODS: Between November 2006 and December 2007, 21 patients older than 65 years of age with intertrochanteric and subtrochanteric fractures were treated with PFNA. The mean duration of follow-up was 12.9 months and the mean age was 74.5 years. RESULTS: The mean operation time was 48.8 minutes (range: 25-90 minutes). The time to ambulation averaged 7.9 days. Eighty point nine percent (17 cases) of the patients returned to their previous walking status at 6 months after operation. The average T-score was -3.3. Eighteen cases (85.7%) achieved acceptable reduction and the mean time to radiologic bony union was 17.4 weeks. The average amount of PFNA blade sliding was 4 mm and the neck-shaft angle was changed to 1.3 degrees varus displacement at the final follow-up. The complications included pulmonary edema in 1 case and protrusion of the PFNA blade into the hip joint in 1 case. CONCLUSION: Because of the reduced operation time, favorable walking ability and low rate of complications, PFNA is an acceptable alternative for fixation of senile osteoporotic peritrochanteric fracture.

The Treatment of Trochanteric Femoral Fracture with Using Proximal Femoral Nail Antirotation (PFNA)

PURPOSE: This study was performed to evaluate the usefulness of proximal femoral nail antirotation (PFNA) for internal fixation of femur trochanteric fractures. MATERIALS AND METHODS: We operated on 36 femur trochanteric fracture patients with performing PFNA from September, 2006 to November, 2008 and we analyzed the operation time, the blood loss, the union time, the tip apex distance (TAD), the Cleveland index, the sliding distance of the blade and the complications. We also evaluated the clinical results according to the recovery of ambulatory function and the functional recovery score. RESULTS: The mean operation time was 54 minutes and the mean amount of blood loss amount was 119cc. Thirty two cases progressed to union within 4 months and 4 cases also progressed to union within 6 months without a further operation. The mean TAD was 16mm and the mean sliding distance was 3.8 mm. Clinically, the mean loss of ambulation ability was 1.2 grades and the Jensen functional recovery score was 1.8. There was one case of back out of the blade, but there was no skin problem. There were no significant complications. CONCLUSION: The findings from this study indicate that PFNA is a useful and reliable choice for the treatment of trochanteric fracture of the femur.

Treatment of the Proximal Femoral Fractures with Proximal Femoral Nail Antirotation (PFNA)

PURPOSE: To analyze the clinical and radiologic results of treatments in proximal femoral fracture with Proximal Femoral Nail-Antirotation (PFNA). MATERIALS AND METHODS: We retrospectively reviewed the results of 21 cases of proximal femoral fracture treated with PFNA from September 2006 to October 2007 which could be followed up for minimum of more than a year. The mean age was 61.5 (20~88) years old. Male were involved in 12 cases, female in 9 cases. The mean follow up was 14.3 (12~18) months. The Garden alignment index, Cleveland index, tip apex distance were evaluated by post-operative radiologic evaluation and complications of bone union, failure of internal fixation and deformity were evaluated by follow up radiologic findings. Clinical results were assessed by social function score of Jensen and mobility score of Parker and Palmer at last follow up. RESULTS: All fractures were united and the mean time to bone union was 15.7 (13~18) weeks. Garden alignment index showed good results of above 'good' in 15 cases (71.4%), Cleveland index showed 14 cases (66.4%) positioning in zone 5 and tip apex distance showed 17.81 (+/-5.65~27.52) mm in radiologic findings. The mean sliding of blade was 1.32 (0.34~2.94) mm in follow up radiologic findings and fracture of distal locking screw area was found in 1 case as a complication. Among 21 cases, the function before injury was completely recovered in 15 cases (71.4%) which were assessed by social function score of Jensen and 13 cases (61.9%) by mobility score of Parker and Palmer. CONCLUSION: We think that PFNA is effective osteosynthetic device for proximal femur fracture with satisfactory radiologic and clinical outcomes.