Chinese Femur Research Articles

Cementless curved endoprosthesis stem for distal femoral reconstruction in a Chinese population: a combined anatomical & biomechanical study

BackgroundThe endoprosthetic knee reconstruction using a current universal femoral stem might not be suitable for local population due to the anatomical difference between Chinese and Western populations. We measured the anatomical parameters of Chinese femurs as reference for stem design, and proposed a cementless, curved, short endoprosthesis stem for the reconstruction of distal femur. This study analyzed the biomechanical performance of the newly designed stem aimed at the identification of better operative strategy.MethodsThe CT–scanning data of femurs derived from 96 healthy Chinese volunteers were imported into the Mimics software, and a segmental measurement strategy was applied to evaluate the radius of curvature (ROC) of the femoral medullary cavity. Then, 4 kinds of endoprosthetic replacement models were created based on the measurement results. Model A: the distal tumor resected femora + straight stem A; Model B: the distal tumor resected femora + curved stem B; Model C: the distal tumor resected femora + curved stem C; Model D: the distal tumor resected femora + curved stem D. Finally, the mechanical difference among these models were compared by finite element analysis.ResultsThe mean femoral ROC of Segment1, 2, 3, 4, 5 measured in the present study was 724.5 mm, 747.5 mm, 1016.5 mm, 1286.5 mm, and 1128 mm, respectively. Based on the femoral ROC of Segment2, the stem ROC of the curved stem B, C, and D was designed as 475 mm, 700 mm, and 1300 mm, respectively. Generally, all endoprosthetic replacement models showed a normal–like stress distribution on the femurs. However, compared to the straight stem, the biomimetic curved stem showed better biomechanical performance both in terms of reducing the extent of the stress shielding of the femur and in terms of minimizing the stress distribution of the implant.ConclusionsThe uncemented, curved, short stem with suitable ROC can perfectly match the Chinese femoral canal morphology which has better mechanical properties than the conventional femoral stem. Thus, this newly designed femoral stem might be an optimized method for treatment of malignant femoral tumours in the Chinese populations in the case that the numerical results are supported by future experimental studies.

Adult femur CT modeling and 3D automatic measurement of anatomical parameters

Objective: To reconstruct a 3D model from adult femur CT scan data and automate a measurement of femoral anatomical parameters to study the characteristics of Chinese femur anatomical parameters. Methods: Using Mimics17.0, models from the CT data of 148 adult patients were established. The completed model was imported into Geomagic Studio and the anatomical landmarks of the femur were extracted to establish 3D coordinate system and unified coordinate system. Programmed with Matlab, using the nearest point iterative ICP algorithm and the 3D automatic extraction algorithm of anatomical landmarks to provide precision positioning, the femoral anatomical parameters were automatically measured and analyzed. The data were compared by using independent sample t test. Results: In this group, the diameter of the male femoral condyle was (84.1±3.6) mm, and it was (74.8±3.3) mm in the female; the anteroposterior diameter of the male femoral condyle was (66.5±3.7) mm, and it was (61.2±3.5) mm in the female; the diameter of the male ball head was (48.8±2.1) mm and it was (43.4±2.2) mm in the female; the differences between the two genders were all statistically significant (t=16.21, 8.84, 15.20, all P<0.05). The male femoral moment radius was (112.5±24.5) mm, and it was (124.7±19.2) mm in the female (t=3.30, P=0.002). The neck angle in male participants was 124.9°±4.0°, and it was 126.1°±5.5° in the female (t=1.40, P>0.05). As the height growed, most of the anatomical parameters increased accordingly. Conclusions: The 3D automatic measurement of femoral anatomical parameters is more reproducible and accurate than manual measurement. It is necessary to establish and enrich the femoral anatomical database to design and develop internal fixation products that meet the needs of Chinese people.

Distal femoral torsion: Differences between caucasians and asians. A multicentre computed tomography study of 515 distal femurs

BackgroundThe posterior condylar angle (PCA) is formed by the posterior condylar line (PCL) and the clinical (or anatomic) transepicondylar line (TEL). The primary objective of this study was to compare the distribution of PCA values in Caucasians and Asians free of knee osteoarthritis. The secondary objectives were to assess PCA variability according to age, gender, and side. HypothesisPCA values differ between Caucasians and Asians. MethodsThe study included the computed tomography scans of 515 healthy femurs, 259 from Asians in China and 256 from Caucasians in France. PCA values were determined based on four landmarks, namely, the two femoral epicondyles and the most prominent point of each condyle at the posterior aspect of the knee. The Mann-Whitney test was chosen to compare PCA values according to ethnic group, gender, and side and Spearman's correlation coefficient to assess correlations with age. Inter-observer and intra-observer variability of PCA measurements was assessed. ResultsMean PCA was 6.0°±2.5° (range, 0°–14°) overall, 6.4° (range, 0.31°–14.1°) in the Asians, and 5.5° (range, 0°–13.1°) in the Caucasians (p<0.0001). Chinese femurs are significantly more internally rotated. No differences in PCA values were found according to age (p=0.4307), gender (p=0.7113), or side (p=0.4304). Inter-observer and intra-observer variability was limited for each of the landmarks, indicating that PCA measurement was reliable. ConclusionPCA varies not only across individuals as reported previously, but also across ethnic groups. This finding further supports routine PCA measurement on imaging studies before total knee arthroplasty. Level of evidenceIII, comparative retrospective study.

Predicting the optimal entry point for femoral antegrade nailing using a new measurement approach.

To establish a new reliable approach for measuring proximal femoral anatomical parameters and determining the optimal entry point of the antegrade intramedullary (IM) nailing. A new method for measuring the proximal femoral anatomy and locating the optimal entry point for the antegrade nailing was developed using Mimics and 3-Matic softwares (Materialise, Haasrode, Belgium). After verifying the reliability of the measurement method using 15 pairs of the femoral models by the intraclass correlation coefficient, the anatomical parameters of 200 Chinese femurs were measured, and statistical analyses were performed to compare the proximal femoral anatomical parameters between different genders or lateralities and determine the most relevant factors of the optimal entry point. Reliability study showed that both intraobserver reliability and interobserver reliability of the current measurement approach were excellent. After independent samples [Formula: see text]-test, the proximal femoral anatomical parameters were shown significant difference between genders. Stepwise regression statistical analyses showed that the most relevant factors of the distances between the optimal entry point and the femoral head centre, the femoral neck axis and the tip of the greater trochanter were the 3D femoral neck-shaft angle (Pearson's [Formula: see text]; the model's [Formula: see text]), the femoral radius (Pearson's [Formula: see text]; the model's [Formula: see text]) and the femoral length (Pearson's r = 0.316; the model's [Formula: see text]), respectively. The current study provided a new and reliable measurement approach to evaluating the anatomical morphology of the proximal femur and revealed the most influential factors on the locations of the simulated optimal entry point for the proximal femoral antegrade IM nailing. Furthermore, this study was useful for establishing methodological basis for future researches and developments of the custom-made IM nailing and affiliated surgical instruments.

Three-Dimensional Analysis of the Curvature of the Femoral Canal in 426 Chinese Femurs

Purpose. The human femur has long been considered to have an anatomical anterior curvature in the sagittal plane. We established a new method to evaluate the femoral curvature in three-dimensional (3D) space and reveal its influencing factors in Chinese population. Methods. 3D models of 426 femurs and the medullary canal were constructed using Mimics software. We standardized the positions of all femurs using 3ds Max software. After measuring the anatomical parameters, including the radius of femoral curvature (RFC) and banking angle, of the femurs using the established femur-specific coordinate system, we analyzed and determined the relationships between the anatomical parameters of the femur and the general characteristics of the population. Results. Pearson's correlation analyses showed that there were positive correlations between the RFC and height (r = 0.339, p < 0.001) and the femoral length and RFC (r = 0.369, p < 0.001) and a negative correlation between the femoral length and banking angle (r = −0.223, p < 0.001). Stepwise linear regression analyses showed that the most relevant factors for the RFC and banking angle were the femoral length and gender, respectively. Conclusions. This study concluded that the banking angle of the femur was significantly larger in female than in male.

Using Three‐Dimensional Computational Modeling to Compare the Geometrical Fitness of Two Kinds of Proximal Femoral Intramedullary Nail for Chinese Femur

Objective. The aim of this study was to use three-dimensional (3D) computational modeling to compare the geometric fitness of these two kinds of proximal femoral intramedullary nails in the Chinese femurs. Computed tomography (CT) scans of a total of 120 normal adult Chinese cadaveric femurs were collected for analysis. With the three-dimensional (3D) computational technology, the anatomical fitness between the nail and bone was quantified according to the impingement incidence, maximum thicknesses and lengths by which the nail was protruding into the cortex in the virtual bone model, respectively, at the proximal, middle, and distal portions of the implant in the femur. The results showed that PFNA-II may fit better for the Chinese proximal femurs than InterTan, and the distal portion of InterTan may perform better than that of PFNA-II; the anatomic fitness of both nails for Chinese patients may not be very satisfactory. As a result, both implants need further modifications to meet the needs of the Chinese population.

Geometric match assessment of three intramedullary nailing systems for Chinese proximal femurs

Objective To obtain morphologic parameters of intramedullary nailing appropriate for proximal femur fractures in Chinese population by assessing the geometric match between 3 kinds of intramedullary nailing and Chinese proximal femurs.Methods One hundred and twenty Chinese femurs were scanned by computed tomography.3D models of Chinese femur were reconstructed on a collection of the CT data using Minics 10.01 software.Parameters of intramedullary nailing designed for proximal femur fractures were measured on the 3D models.3D models of internal fixation of the proximal femur with 3 kinds of intramedullary nailing,Proximal Femoral Nail Antirotation(PFNA),PFNA-Ⅱ and InterTan,were reconstructed using proE 4.0 software.The 3D models of 3 intramedullary nailing systems were imported into the Mimics software to match the 3D models of Chinese femur.The geometric match was assessed between the 3nailing systems and 20 Chinese femurs,which were randomly selected from 120 samples.The relative positions between the nail and the lateral wall of femur as well as between the nail and the top of greater troehanter were observed.Results The average protrusion of the nail into the lateral femoral cortex was significantly thicker in PFNA(1.51 ± 0.58 mm)than in PFNA-Ⅱ(0.12 ±0.21 mm)and InterTan(0.33 ± 0.26 mm)(F =57.189,P ＜ 0.001).The average extension distance of the nail beyond the top of the proximal femur was significantly shorter in InterTan(0.25 ± 0.34 mm)than in PFNA(3.47 ± 0.85 mm)and PFNA-Ⅱ(4.11 ±0.92 mm)(F =67.600,P ＜ 0.001).Conclusions PFNA-Ⅱ,as an improvement of PFNA,has evidently reduced intraoperative invasion to the lateral wall of femur,but does not solve the problem of proximal length.InterTan,with evidently reduced invasion to the lateral wall of femur and an appropriate proximal length,has a better anatomic match for the Chinese femur. Key words: Femur; Fracture fixation, intramedullary; Bone nails; Anatomy, comparative

Sagittal bowing of the distal femur in Chinese patients who require total knee arthroplasty

Purposes: The importance of the femoral sagittal bowing on total knee arthroplasty is under-recognized. The bowing could lead to potential errors in positioning of the femoral component if it is ignored. We aimed to document the femoral sagittal bowing at different segments of the Chinese femur and to discuss the implications of this sagittal bowing on total knee arthroplasty. Methods: One hundred lateral radiographs of the entire lower limbs of 85 Chinese patients admitted for total knee arthroplasty were digitized. The radii of curvature of the intramedullary canal of the proximal, middle and distal one-third of the femora were measured. Results: The average age of the patients was 67.3 years. The radii of curvature of the proximal, middle and distal one-third of the femora were 1081.6, 926.2 and 715.1 mm, respectively. The distal one-third of the femora was significantly more bowed than the other parts of the femora ( p < 0.001). The distal femoral bowing was more profound in rheumatoid patients and in those with a short femur. Conclusions: The lateral contour of the Chinese femur is like a hockey stick. This exaggerated sagittal bowing in the Chinese femur can affect the final sagittal position of the femoral component and has implications for the choice of implant design. In revision setting, a long and straight press-fit stem might either endanger the anterior cortex or deflect the femoral component to an abnormally extended position.

Distal rotational alignment of the Chinese femur and its relevance in total knee arthroplasty

The rotational alignments of the distal femur in southern Chinese subjects were investigated. Chinese femurs are significantly more externally rotated. This is new evidence to suggest a racial difference in the distal femoral geometry. During total knee arthroplasty, a common recommendation is to allow 4° of external rotation. The clinical significance of our study is that this need to be modified to 6° for Chinese women and 5° for Chinese men. This racial difference can be incorporated into a new concept of “a mountain and a molehill.” This concept is presented in this report.

Sonographic Evaluation of the Fetal Femur Length in the Chinese Population

Sonograms of 128 Chinese fetuses scanned between 16-20 weeks' gestational age, with last menstrual period and average sonographic age corresponding by ± 10 days, were evaluated retrospectively. The fetal femur length was measured longitudinally using a linear phased array transducer. The observed femur lengths were compared with the corresponding data in Hadlock's chart, which is based on a white middle class population. Results indicated that the Chinese femur length was shorter than the Hadlock values by 0.56 mm. The analysis of variance revealed that this difference was consistent throughout pregnancy. Although the findings were statistically significant, they do not indicate a need for an adjustment to the Hadlock chart, as 0.56 mm would suggest a difference of only O.3 weeks.

Geometric mismatch of the Gamma nail to the Chinese femur.

The geometric mismatch of the femoral component of the Gamma nail to the Chinese femora resulted in intraoperative complications. To provide scientific data for modification of the implant, 28 pairs of normal Chinese femora were studied with the 3-dimensional reconstruction from the computed tomography scan data. Measurements were taken from the reconstituted drawings, and the anthropometric data were applied in the modification of the implant. This study is the first report on the application of Chinese anthropometric data on the design of a trauma implant. It is hoped that a larger scale of the study will provide a more comprehensive data base for wider application to orthopaedic implant design in the future.

Sexual dimorphism in the Chinese femur

In the last decade, there has been renewed interest in contemporary and ancient Chinese skeletal populations. The purpose of this research is the osteometric assessment of sexual dimorphism in recent mainland Chinese cemetery populations and the development of discriminant function standards to determine sex from the femur. The sample for this project was composed of 87 adult skeletons from cemeteries in Chang Chun City (Liaoning) and Qingdao (Shandong). A total of six femoral measurements was taken and subjected to SPSS discriminant function analysis. Three dimensions were selected by the stepwise analysis in the following order: distal epiphyseal breadth, maximum length, and anteroposterior diameter of the midshaft. This function produced 92.3% classification accuracy. Direct analysis revealed that distal epiphyseal breadth alone provided an even better separation (94.9%). The remaining functions were less discriminating. In conclusion, distal epiphyseal breadth is the most dimorphic part of the Chinese femur. This contrasts with earlier findings on American Whites and Blacks in which head diameter is the most dimorphic. This and other significant differences underscore the necessity of obtaining population-specific values for metric analysis of sex. These findings also support previous studies indicating that linear dimensions such as length are often less discriminating than breadth and circumference measurements in long bones. Finally, the fact that maximum dimorphism was found at a major weight-bearing joint suggests that the size differentials between Chinese males and females may be in large part functional in nature, perhaps arising from sex-specific physical activities.

Sex Determination of Chinese Femur by Discriminant Function

The objective of this study was to provide a method of sex determination for Chinese femur, especially for fragmentary remains. Statistical analysis of 17 measurements based on 141 northeastern Chinese femora shows that all measurements have significant sex differences. Sex determination by the midpoint method of a single measurement can obtain an average accuracy of 76.8%. The results indicate that of all dimensions the maximum head diameter is the best discriminator of sex. It alone can determine the sex of a femur with 85.1% accuracy. The results also show that maximum head diameter, transverse head diameter, epicondylar breadth, upper breadth, and medial condylar length have higher sexual dimorphisms than the dimensions of length. According to the result to stepwise discriminant analysis and the need for sexing fragmentary remains, 22 discriminant functions composed of various combinations of variables were calculated which can determine the sex of the femur correctly 82.3 to 87.2%. The methods of sex determination provided by this paper can be used to sex poorly preserved femora.

Some anthropometric studies of the femur of the male West Malaysian Chinese.

AbstractMeasurements and indices were made on 120 male West Malaysian Chinese femora. The findings are compared with appropriate ones from some Eastern and Western series. The Chinese femur is smaller than all the other groups listed except for the Japanese femur. There is a high degree of significance between the maximum and bicondylar lengths of the Chinese femur against those of the Australian aborigine, Maori and White American. The head of the femur is greater in the Maori and White American than the Chinese. The platymeric index is nearly as high as the White American. The difference in the robusticity index of the femur between the Australian aborigine, Maori, White American and the present series is small. The collodiaphyseal angle of the Chinese femur is large being greater than the Australian aborigine, Finn and White American. The angle of torsion of 11.8° is within the range for Westerners with a high incidence of retroversion unlike the Australian aborigine and Maori where no retroversion is seen. Although most of the means of the measurements and indices of the femur show a highly significant difference between the present series and some of the other groups listed there is a wide overlap for measurements of the Chinese femur to be used for racial identification.