scholarly journals Finite element analysis of two cephalomedullary nails in treatment of elderly reverse obliquity intertrochanteric fractures: zimmer natural nail and proximal femoral nail antirotation-ΙΙ

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Jian Chen ◽  
Jian-xiong Ma ◽  
Ying Wang ◽  
Hao-hao Bai ◽  
Lei Sun ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Fixation ◽  
Intertrochanteric Fracture ◽  
Proximal Femoral Nail ◽  
Intertrochanteric Fractures ◽  
Element Analysis ◽  
Femoral Nail ◽  
Unstable Intertrochanteric Fracture ◽  
Proximal Femoral Nail Antirotation

Abstract Background More elderly patients are suffering from intertrochanteric fractures. However, the choice of internal fixation is still controversial, especially in the treatment of unstable intertrochanteric fracture; thus, previous implants continue to be improved, and new ones are being developed. The purpose of our study was to compare the biomechanical advantages between the zimmer natural nail (ZNN) and proximal femoral nail antirotation-II (PFNA-II) in the treatment of elderly reverse obliquity intertrochanteric fractures. Methods A three-dimensional finite element was applied for reverse obliquity intertrochanteric fracture models (AO31-A3.1) fixed with the ZNN or PFNA-II. The distribution, peak value and position of the von Mises stress and the displacement were the criteria for comparison between the two groups. Results The stresses of the internal fixation and femur in the ZNN model were smaller than those in the PFNA-II model, and the peak values of the two groups were 364.8 MPa and 171.8 MPa (ZNN) and 832.3 MPa and 1795.0 MPa (PFNA-II). The maximum amount of displacement of the two groups was similar, and their locations were the same, i.e., in the femoral head vertex (3.768 mm in the ZNN model and 3.713 mm in the PFNA-II model). Conclusions The displacement in the two models was similar, but the stresses in the implant and bone were reduced with the ZNN. Therefore, the ZNN implant may provide biomechanical advantages over PFNA-II in reverse obliquity intertrochanteric fractures, as shown through the finite element analysis. These findings from our study may provide a reference for the perioperative selection of internal fixations.

scholarly journals A Finite Element Analysis and Cyclic Load Experiment on an Additional Transcortical-Type Hole Formed Around The Proximal Femoral Nail System’s Distal Locking Screw

2021 ◽  
Author(s):  
Hong Man Cho ◽  
Seung Min Choi ◽  
JiYeon Park ◽  
Young Lee ◽  
Jung Hyung Bae
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Stress ◽  
Intertrochanteric Fracture ◽  
Proximal Femoral Nail ◽  
Element Analysis ◽  
Distal Locking ◽  
Femoral Nail ◽  
Hole Model ◽  
Locking Screw

Abstract Background A complication associated with the distal locking screw used in the proximal femoral nail (PFN) system is the formation of accidental additional holes. We hypothesized that an increase in stress around additional holes is a relevant factor contributing to fractures. This study aimed to evaluate stress changes in the cortical bone around additional screw holes using finite element analysis. Methods Proximal femoral nail PFN antirotation (PFNA)-II (Synthes, Solothurn, Switzerland) was inserted into a femur model. An additional 4.9-mm transcortical hole was made either anteriorly (anterior hole model) or posteriorly (posterior hole model) to the distal locking screw. Finite element analysis was used to calculate compression, tension, and load limits to investigate stress around additional holes with respect to the direction of screw penetration and degree of osteoporosis. The results were then compared with those of mechanical testing. A 31A-21 type intertrochanteric fracture was applied. As a control group, a model without additional holes (no-hole model) was developed. Repeated load-loading tests were performed on 10 model bones per model group. Results Tensile stress was significantly greater in the no-hole model when additional screw holes were present, and the anterior hole showed a higher maximum stress value than the posterior hole did, suggesting that the anterior hole was more susceptible to fracture. The change in tensile stress first appeared in the hole around the lateral cortical bone and proceeded to the medial side. Biomechanical testing showed that fractures around the distal locking screw occurred in 0 cases of the no-hole, 10 of anterior hole, and 9 of the posterior hole models. Conclusions During PFN surgery for intertrochanteric fracture, holes with distal locking screws fixed and removed at the anterior and posterior of the nail can be a risk factor for fractures in the surrounding area.

AO/OTA 31A2 and 31A3 Intertrochanteric Fractures Managed by Proximal Femoral Nail Antirotation (PFNA)

2021 ◽  
Vol 15 (10) ◽  
pp. 2616-2618
Author(s):  
Zamir Hussain Tunio ◽  
Rizwan Ali Jhatiyal ◽  
Muhammad Azeem Akhund ◽  
M. Kashif Abbasi ◽  
S. Muhammad Ali ◽  
...  
Keyword(s):  
Intertrochanteric Fracture ◽  
Proximal Femoral Nail ◽  
Harris Hip Score ◽  
Psychiatric Disease ◽  
Unstable Fracture ◽  
Intertrochanteric Fractures ◽  
Femoral Nail ◽  
Intramedullary Device ◽  
Unstable Intertrochanteric Fracture ◽  
Proximal Femoral Nail Antirotation

Aim: To study the clinical and radiological outcome of unstable intertrochanteric fracture AO/OTA 31A2, 31A3 fixed by proximal femoral nail antirotation Study design: Descriptive cross sectional study. Place and duration of study: Department of Orthopedic Surgery and Traumatology, Pir Abdul Qadir Shah Jilani Institute of Medical Sciences, Gambat, Sindh from 1st January 2016 to 31st December 2019. Methodology: Forty four cases having intertrochanteric fracture AO/OTA 31A2, 31A3 with age ranging from 18 year to 55 year of either gender were selected; patients having close fracture, who were willing were included in the study, while patients older than 55 year and younger than 18 year, AO/OTA 31A1 fracture, open fracture, bilateral injuries, smoker, alcoholic, drug addicted, poly-trauma, pathological fracture and history of poor compliance, psychiatric disease were excluded. Results: There were 26(59.09%) males and 18(40.91%) females with mean age was 41.3±7.7 years. Regarding classification; AO/OTA 31A2 were 33 (75%), and 31A3 were 11 (25%). Mean time for union was 18.5±3.55 weeks. The average time of follow-up was 48.5±6.6 weeks. Harris Hip Score was excellent (90-100) in 31(70.45%), good (80-89) in 7(15.91%), fair (70-80) in 3 (6.81%) and poor (<70) in 3 (6.81%). Conclusion: Intramedullary device proximal femoral nail antirotation can be labelled as implant of choice for unstable intertrochanteric fractures AO/OTA 31A2, 31A3, with fruitful clinical and radiological outcomes, and with fewer complications. Hip Harris score was excellent-good in 86% of the patients. Key words: Proximal femoral nail antirotation (PFNA), AO/OTA 31A2, 31A3, Intertrochanteric, unstable fracture

scholarly journals Proximal femoral nail antirotation II in fixation of intertrochanteric fractures: retrospective and prospective observational study

2020 ◽  
Vol 6 (3) ◽  
pp. 593
Author(s):  
Arvind Kumar S. M. ◽  
Arun Kumar B.
Keyword(s):  
Blood Loss ◽  
Intertrochanteric Fracture ◽  
Interquartile Range ◽  
Proximal Femoral Nail ◽  
Intertrochanteric Fractures ◽  
X Rays ◽  
Femoral Nail ◽  
Unstable Intertrochanteric Fracture ◽  
The Mean ◽  
Proximal Femoral Nail Antirotation

<p class="abstract"><strong>Background:</strong> Intertrochanteric fractures occur mostly in elderly patients, and the outcome may be extremely poor if there is prolonged bed-rest. The best treatment for trochanteric fracture remains controversial. Proximal femoral nail antirotation (PFNA) II has excellent fit as the design is adapted to the anatomical situation of small statured patients also. It has a medial lateral angle of 5 degrees. It has several distal locking options viz static/dynamic. Objective of this study was to observe the operating time, blood loss and fracture union in intertrochanteric fractures treated with PFNA II from the data collected from patient’s case sheets and post-operative X-rays.</p><p class="abstract"><strong>Methods:</strong> 25 patients who were operated with PFNA II for unstable intertrochanteric fracture were selected using random selection and following parameters were noted from the records.<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean age of the participants is 70.72±8.55 years with range from 52 years to 89 years. The mean duration was 1.98 hours ±0.66. The median duration was 2 with interquartile range from 1.5 to 2.5 hours. Mean blood loss was estimated to be 390 ml±62.78. The median blood loss was 370 ml with interquartile range from 360 to 420 ml.</p><p class="abstract"><strong>Conclusions:</strong> The PFNA II is an ideal implant for unstable intertrochanteric fracture since stable intramedullary fixation can be achieved with almost 100% union in the studied population.</p>

scholarly journals Cement augmentation of the proximal femoral nail antirotation for the treatment of two intertrochanteric fractures - a comparative finite element study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Liqin Zheng ◽  
Xinmin Chen ◽  
Yongze Zheng ◽  
Xingpeng He ◽  
Jingxiong Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Maximum Stress ◽  
Intertrochanteric Fracture ◽  
Cement Augmentation ◽  
Proximal Femoral Nail ◽  
Intertrochanteric Fractures ◽  
Unstable Intertrochanteric Fracture ◽  
Helical Blade ◽  
Proximal Femoral Nail Antirotation

Abstract Background There are concerns regarding initial stability and cutout effect in proximal femoral nail antirotation (PFNA) treating intertrochanteric fractures. No study have used finite element analysis (FEA) to investigate the biomechanics. This study aimed to compare the cutout effect, stress and displacement between stable (AO31-A1.3) and unstable (AO31-A2.2) intertrochanteric fractures treated by cement augmented PFNA. Methods Four femoral finite element models (FEMs) were constructed and tested under the maximum loading during walking. Non-augmented and augmented PFNA in two different intertrochanteric fractures were respectively simulated, assuming Tip Apex Distance (TAD) < 25 mm within each FEM. The cutout effect, stress and displacement between femur and PFNA were compared in each condition. Results Cutout effect was observed in both non-augmented femoral head and was more apparently in unstable intertrochanteric fracture model. After reinforced by bone cement, no cutout effect occurred in two models. Stress concentration were observed on medial part of intertrochanteric region and the proximal part of helical blade before augmented while were observed on femoral shaft and the conjunction between blade and nail after augmented in both FEMs. Displacement mainly appeared on femoral head and the helical blade tip before augmented while distributed moderately on intertrochanteric region and the upper part of nail after augmented in both FEMs. The maximum stress and displacement value of femur decreased both in stable and unstable model after augmented but was more significantly in the unstable one. The maximum stress and displacement value of PFNA increased both in stable and unstable model after augmented but was more significantly in the unstable one. Conclusion Our FEA study indicated that the cement augmentation of the PFNA biomechanically enhances the cutout resistance in intertrochanteric fracture, this procedure is especially efficient for the unstable intertrochanteric fracture.

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