Weight-bearing Area Of Femoral Head Research Articles

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

BackgroundThe 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.MethodsFemoral 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.ResultsSEM 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.ConclusionsThis 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.

Finite Element Modeling of Proximal Femur with Quantifiable Weight-Bearing Area in Standing Position

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 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. 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. Funding Statement: This study was supported by grants from the National Natural Science Foundation of China (Grant No. 81873327), Natural Science Foundation of Guangdong (Grant No. 2015A030313353), Scientific Research Project of Chinese Medicine of Guangdong (Grant No. 20191116) and Excellent Doctoral Dissertation Incubation Grant of First Clinical School of Guangzhou University of Chinese Medicine (Grant No. YB201802). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: This study was conducted in agreement with the Declaration of Helsinki and its later amendments or comparable ethical standards and had been approved by the ethics board of The First Affiliated Hospital of Guangzhou University of Chinese Medicine (No: Y《2019》118).