scholarly journals Biomechanical Analysis of Fibular Graft Techniques for Nontraumatic Osteonecrosis of Femoral Head: A Finite Element Analysis

2020 ◽  
Author(s):  
Jian Xu ◽  
Shi Zhan ◽  
Ming Ling ◽  
Dajun Jiang ◽  
Hai Hu ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Healthy Subject ◽  
Proximal Femur ◽  
Weight Bearing ◽  
Biomechanical Properties ◽  
Patient Specific ◽  
Structural Stiffness ◽  
Osteonecrosis Of Femoral Head ◽  
Weight Bearing Area

Abstract Background: Free vascularized fibula graft (FVFG) technique has achieved the most consistent successful therapeutic effect on young patients diagnosed as nontraumatic osteonecrosis of femoral head (NONFH), of which the Core Track Technique (CTT) has been the most commonly used. As an alternative to CTT, the modified Light Bulb Technique (LBT) was reported to have a higher success rate. However, its biomechanical characters have been poorly understood. This study aimed to investigate the biomechanical properties of modified LBT in treating NONFH by comparing with CTT.Methods: Two types (C1 and C2) of NONFH finite element models were established from a healthy subject according to the Japanese Investigation Committee (JIC) classification, and CTT and LBT procedures were simulated in each type of the models. The average Von Mises stresses and stiffness of the proximal femur were calculated by applying 250% body weight loading on femoral head to simulate walking condition. In addition, two patient-specific models were built and simulated under the same boundary condition for the further validation of LBT.Results: In the healthy subject-derived models, both LBT and CTT resulted in reduced stresses in the weight-bearing area, central femoral head, femoral neck, and trochanteric and subtrochanteric regions, and increased structural stiffness after surgery. In the weight-bearing area, CTT reduced more stresses than LBT (36.19% vs 31.45%) for Type C1, while less reduction (23.63% vs 26.76%) for Type C2. In patient-specific models, stiffness and stresses of before and after surgery were also increased and reduced respectively, which is consistent with healthy subject-derived models.Conclusion: LBT and CTT have different biomechanical performance on different JIC type of NONFH. In terms of preventing the collapse of femoral head, LBT may be more effective for JIC Type C2, which could alternatively be chosen, while for JIC Type C1, CTT is still a better choice. Both techniques can improve biomechanical properties of NONFH with patients’ proximal femur stress reduced and structural stiffness enhanced.

scholarly journals Finite element modeling of proximal femur with quantifiable weight-bearing area in standing position

2020 ◽  
Author(s):  
Yang Peng ◽  
Tian-Ye Lin ◽  
Jing-Li Xu ◽  
Hui-Yu Zeng ◽  
Da Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Proximal Femur ◽  
Physical Phenomenon ◽  
Weight Bearing ◽  
Positional Distribution ◽  
Standing Position ◽  
Fe Model ◽  
X Ray ◽  
Weight Bearing Area

Abstract BackgroundThe positional distribution and size of the weight-bearing area of femoral head in the standing position as well as the direct active surface of joint force can directly affect the result of finite element (FE) stress analysis, however in most studies related separate FE models of femur, the division of this area is vague, imprecise and un-individualized. The purpose of this study was to quantify the positional distribution and size of the weight-bearing area of femoral head in standing position by a set of simple methods, to realize individualized reconstruction of proximal femur FE model.MethodsFive adult volunteers were recruited for X-ray and CT examination in the same simulated bipedal standing position with a specialized patented device. We extracted these image data, calculated the 2D weight-bearing area on X-ray image, reconstructed the 3D model of proximal femur based on CT data, and registered them to realize the 2D weight-bearing area to 3D transformation as the quantified weight-bearing surface. One of the 3D models of proximal femur was randomly selected for finite element analysis (FEA), and we defined three different loading surfaces, and compared their FEA results.ResultsA total of 10 weight-bearing surfaces in 5 volunteers were constructed, they were mainly distributed on the dome and anterolateral of femoral head with crescent shape, in the range of 1,218.63mm2 - 1,871.06mm2. The results of FEA showed stress magnitude and distribution in proximal femur FE models among three different loading conditions were significant differences, the loading case with quantized weight-bearing area was more in accordance with the physical phenomenon of the hip.ConclusionThis study confirmed an effective FE modeling method of proximal femur, which can quantify weight-bearing area to define more reasonable load surface setting without increasing the actual modeling difficulty.

scholarly journals Allograft Fibula Combined with Cannulated Screw for Femoral Head Necrosis: A Finite Element Analysis

2021 ◽  
Author(s):  
Gan Zhao ◽  
Ming Liu ◽  
Bin Li ◽  
Tianye Lin ◽  
JingLi Xu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Head ◽  
Cortical Bone ◽  
Maximum Stress ◽  
Weight Bearing ◽  
Cannulated Screw ◽  
Element Analysis ◽  
Osteonecrosis Of Femoral Head ◽  
Weight Bearing Area

Abstract Background: Osteonecrosis of femoral head (ONFH) is characterized by high incidence and disability. Allograft fibula combined with cannulated screw has been extensively applied for treating Osteonecrosis of femoral head. However, its biomechanical outcomes remain unclear. The present study aimed to investigate the optimal placement of the allograft fibula and cannulated screw for treating ONFH.Methods: Two types (C1 and C2) of NONFH finite element models were built based on a healthy subject and the Japanese Investigation Committee (JIC) classification system. The allograft fibula combined with cannulated screw was simulated in the respective type of the model. Different models were built by complying with the different positions of allograft fibula and cannulated screw (below model, posteriorly below model, anteriorly below model and anteriorly above model). Furthermore, a comparison was drawn on the maximum stress value and the mean stress value of the subchondral cortical bone of femoral head weight-bearing area.Results: As indicated from the finite element analysis, normal femoral head, necrotic femoral head and postoperative femoral head achieved the different maximum stress values, and the maximum stress value achieved by necrotic femoral head significantly reached over that of normal femoral head. After the operation, the maximum stress value of subchondral cortical bone in the weight-bearing area of the femoral head was noticeably down-regulated compared with that before the operation (necrotic femoral head). When the cannulated screw was directly below the fibula, subchondral cortical bone in the weight bearing area of femoral head achieved the smallest maximum stress value and average stress value, which showed a statistical difference from those of other models (P<0.05).Conclusion: Allograft fibula combined with cannulated screw is capable of significantly reducing the stress of subchondral cortical bone in the weight-bearing area of the ONFH femoral head, as well as down-regulating the stress concentration in the ONFH weight-bearing area. For JIC C1 and C2 osteonecrosis of the femoral head, when administrated with allograft fibula combined with cannulated screw, the optimal biomechanics was the cannulated screw located just directly below the fibula.

scholarly journals Finite element modeling of proximal femur with quantifiable weight-bearing area in standing position

2020 ◽  
Author(s):  
Peng Yang ◽  
Tian-Ye Lin ◽  
Jing-Li Xu ◽  
Hui-Yu Zeng ◽  
Da Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Proximal Femur ◽  
Physical Phenomenon ◽  
Weight Bearing ◽  
Positional Distribution ◽  
Standing Position ◽  
Fe Model ◽  
X Ray ◽  
Weight Bearing Area

Abstract Background The positional distribution and size of the weight-bearing area of femoral head in the standing position as well as the direct active surface of joint force can directly affect the result of finite element (FE) stress analysis.However,the division of this area was vague, imprecise and un-individualized in most studies related separate FE models of femur. The purpose of this study was to quantify the positional distribution and size of the weight-bearing area of femoral head in standing position by a set of simple methods, to realize individualized reconstruction of proximal femur FE model. Methods Five adult volunteers were recruited for X-ray and CT examination in the same simulated bipedal standing position with a specialized patented device. We extracted these image data, calculated the 2D weight-bearing area on X-ray image, reconstructed the 3D model of proximal femur based on CT data, and registered them to realize the 2D weight-bearing area to 3D transformation as the quantified weight-bearing surface. One of the 3D models of proximal femur was randomly selected for finite element analysis (FEA), and we defined three different loading surfaces, and compared their FEA results. Results A total of 10 weight-bearing surfaces in 5 volunteers were constructed, they were mainly distributed on the dome and anterolateral of femoral head with crescent shape, in the range of 1,218.63mm2 − 1,871.06mm2. The results of FEA showed stress magnitude and distribution in proximal femur FE models among three different loading conditions were significant differences, the loading case with quantized weight-bearing area was more in accordance with the physical phenomenon of the hip. Conclusion This study confirmed an effective FE modeling method of proximal femur, which can quantify weight-bearing area to define more reasonable load surface setting without increasing the actual modeling difficulty.

scholarly journals Degradation of subchondral bone collagen in the weight-bearing area of femoral head is associated with osteoarthritis and osteonecrosis

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Zongyi Wu ◽  
Bingzhang Wang ◽  
Jiahao Tang ◽  
Bingli Bai ◽  
Sheji Weng ◽  
...  
Keyword(s):  
Femoral Head ◽  
Trabecular Bone ◽  
Subchondral Bone ◽  
Weight Bearing ◽  
Collagen Fibers ◽  
Bone Collagen ◽  
Control Group ◽  
Neck Fracture ◽  
Hematoxylin And Eosin ◽  
Weight Bearing Area

Abstract Background The aim of the study was to evaluate the change of subchondral bone collagen and trabecular bone in the weight-bearing area of femoral head from patients with osteoarthritis (OA) or osteonecrosis of femoral head (ONFH), and discuss the effect of collagen degradation on OA and ONFH. Methods Femoral heads from patients with femoral neck fracture (FNF) were collected as control group. All collected samples were divided into OA group (N = 10), ONFH group (N = 10), and FNF group (N = 10). Differences of subchondral bone collagen were compared through scanning electron microscope (SEM) observation, immunohistochemistry staining, and Masson’s trichrome staining. Alteration of subchondral bone was displayed through hematoxylin and eosin (H&E) staining and gross morphology. Results SEM results showed that collagen fibers in OA and ONFH group appeared to be thinner, rougher, sparser, and more wizened. Immunohistochemistry and Masson’s trichrome staining results demonstrated that the content of collagen fibers in the OA and ONFH group was obviously less than the FNF group. H&E staining results showed that trabecular bone in OA and ONFH group appeared to be thinner and ruptured. Gross morphology results showed that the degeneration and destruction of cartilage and subchondral bone in OA and ONFH group were severer than FNF group. The characteristics mentioned above in ONFH group were more apparent than OA group. Conclusions This study revealed that degradation of collagen fibers from subchondral bone in the weight-bearing area of femoral head was associated with OA and ONFH, which may help to find new therapeutic strategies of the diseases.

Hip Joint Contact Pressure Distribution During Pavlik Harness Treatment of an Infant Hip: A Patient-Specific Finite Element Model

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Behzad Vafaeian ◽  
Samer Adeeb ◽  
Marwan El-Rich ◽  
Dornoosh Zonoobi ◽  
Abhilash R. Hareendranathan ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Contact Pressure ◽  
Treatment Success ◽  
Element Model ◽  
Developmental Dysplasia ◽  
Patient Specific ◽  
Pavlik Harness ◽  
Excessive Pressure ◽  
Joint Contact Pressure

Developmental dysplasia of the hip (DDH) in infants under 6 months of age is typically treated by the Pavlik harness (PH). During successful PH treatment, a subluxed/dislocated hip is spontaneously reduced into the acetabulum, and DDH undergoes self-correction. PH treatment may fail due to avascular necrosis (AVN) of the femoral head. An improved understanding of mechanical factors accounting for the success/failure of PH treatment may arise from investigating articular cartilage contact pressure (CCP) within a hip during treatment. In this study, CCP in a cartilaginous infant hip was investigated through patient-specific finite element (FE) modeling. We simulated CCP of the hip equilibrated at 90 deg flexion at abduction angles of 40 deg, 60 deg, and 80 deg. We found that CCP was predominantly distributed on the anterior and posterior acetabulum, leaving the superior acetabulum (mainly superolateral) unloaded. From a mechanobiological perspective, hypothesizing that excessive pressure inhibits growth, our results qualitatively predicted increased obliquity and deepening of the acetabulum under such CCP distribution. This is the desired and observed therapeutic effect in successful PH treatment. The results also demonstrated increase in CCP as abduction increased. In particular, the simulation predicted large magnitude and concentrated CCP on the posterior wall of the acetabulum and the adjacent lateral femoral head at extreme abduction (80 deg). This CCP on lateral femoral head may reduce blood flow in femoral head vessels and contribute to AVN. Hence, this study provides insight into biomechanical factors potentially responsible for PH treatment success and complications.

scholarly journals Three-dimensional finite element analysis of silk protein rod implantation after core decompression for osteonecrosis of the femoral head

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Liangta Huang ◽  
Feiyan Chen ◽  
Siqun Wang ◽  
Yibing Wei ◽  
Gangyong Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Surface Stress ◽  
Weight Bearing ◽  
Three Dimensional ◽  
Core Decompression ◽  
Silk Protein ◽  
Head Weight ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract Background Several methods are available for the treatment of early-stage osteonecrosis of the femoral head. Core decompression with implantation is a widely-used treatment. However, no single implant is recognized as the most effective way to prevent disease progression. Silk has high strength and resiliency. This study explored the possibility of a strong and resilient silk protein biomaterial as a new alternative implant. Methods We investigated the biomechanical properties of the silk protein material by regular compression, torsion, and three-point bending tests. We established three-dimensional finite element models of different degrees of femoral head osteonecrosis following simple core decompression, fibula implantation, porous tantalum rod implantation, and silk protein rod implantation. Finally, we compared the differences in displacement and surface stress under load at the femoral head weight-bearing areas between these models. Results The elastic modulus and shear modulus of the silk protein material was 0.49GPa and 0.66GPa, respectively. Three-dimensional finite element analyses demonstrated less displacement and surface stress at the femoral head weight-bearing areas following silk protein rod implantation compared to simple core decompression (p < 0.05), regardless of the extent of osteonecrosis. No differences were noted in the surface deformation or surface stress of the femoral head weight-bearing areas following silk protein rod, fibula or tantalum rod implantation (p > 0.05). Conclusions When compared with simple core decompression, silk protein rod implantation demonstrated less displacement and surface stress at the femoral head weight-bearing area, but more than fibula or tantalum rod implantation. Similar effects on the surface stress of the femoral head between the silk rod, fibula and tantalum rod implantations, combined with additional modifiable properties support the use of silk protein as a suitable biomaterial in osteonecrosis surgery.

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