Comparing Two Different Automatic Methods to Measure Femoral Neck-Shaft Angle Based on PointNet++ Network

Bacnground: Accurate measurement of the femoral neck-shaft angle (NSA) is of great significance for diagnosing hip joint diseases and preoperative planning of total hip arthroplasty. However, the fitting lines of the femoral neck and femoral shaft did not always intersect in 3D space. Thus, it is unclear whether there is a difference between 2D and 3D methods for measuring NSA. Methods: The femoral point cloud datasets from 310 subjects were segmented into three regions, including the femoral head, femoral neck, and femoral shaft using PointNet++. We created a projection plane to simulate the hip anteroposterior radiograph and fitted the femoral neck axis and femoral shaft axis to complete the 2D measurement, while we directly fitted the two axes in space to complete the 3D measurement. Also, we conducted the manual measurement of the NSA. We verified the accuracy of the segmentation and compared the results of the two automatic and manual methods. Results: The Dice coefficient of femoral segmentation reached 0.9746, and MIoU of that was 0.9165. No significant difference was found between any two of the three methods. While comparing the 2D and 3D methods, the average accuracy was 98.00%, and the average error was 2.58°. Conclusion: This paper proposed two accurate and automatic methods to measure the NSA based on a 2D plane and a 3D model respectively. Although the femoral neck and femoral shaft axes did not intersect in 3D space, the NSAs obtained by 2D and 3D methods were basically consistent.

Assessment of Femoral Neck-shaft Angle on Plain X-rays and its Clinical Implications

Background: Femoral neck-shaft angle is an important parameter for evaluating the biomechanics of the hip joint. It plays a pivotal role in surgeries for developmental dysplasia of the hip, neuromuscular disorders of the lower limb, proximal femoral fractures, Total Hip Arthroplasty, Perthes disease etc., It is also considered to hold an extensive bearing while designing orthopaedic implants. Aim: This study aimed to evaluate the femoral neck-shaft angle of proximal femur on plain radiographs of our local population Study Design: Retrospective study Methods: This cross-sectional study was done at Saveetha medical college hospital, a tertiary care institute in Chennai. 50 pelvic X-rays of patients aged between 30 to 70 who presented to the outpatient or emergency care department were used in the study. Using a goniometer the femoral neck shaft angle was measured in the plain X - ray. Results: The mean age of the population in our study was 47.12. And the mean femoral neck shaft was 132.6 in males and 124.9 in females.

Cartilage Thickness and Bone Shape Variations as a Function of Sex, Height, Body Mass, and Age in Adult Knees.

The functional relationship between bone and cartilage is modulated by mechanical factors. Scarce data exist on the relationship between bone shape and the spatial distribution of cartilage thickness. This study has three aims: first, to characterise the coupled variation in knee bone morphology and cartilage thickness distributions in knees with healthy cartilage. The second aim was to investigate this relationship as a function of sex, height, body mass, and age. The third aim was to characterise the morphological differences between males and females. MR images of 51 adult knees (28.4±4.1 years) were obtained from a previous study and used to train a statistical shape model of the femur, tibia, and patella and their cartilages. Five linear regression models were fitted to characterise morphology as a function of sex, height, body mass, and age. A logistic regression classifier was fitted to characterise morphological differences between males and females, and 10-fold cross-validation was performed to evaluate the models’ performance. Our results showed that cartilage thickness and its distribution was coupled to bone morphology, including both size (mode 1) and shape variations (mode 2 onwards). The first three shape modes captured over 90% of the variance and described the overall size, diaphysis size, femoral shaft angle, and corresponding changes to the spatial distribution of the cartilages. These modes were sex-linked (p < .0001, p < .05, p < .01, for modes 1, 2, and 3 respectively) and could classify sex with an accuracy of 94.1% (95% CI [83.8%, 98.8%]). Height was a predictor of joint size (p <. 0001) and diaphysis size (p < .05). Body mass was a predictor of joint size (p < .1) and femoral shaft angle (p < .1). Age was not correlated with any of the modes. This study demonstrated the coupled relationship between bone and cartilage, showing that cartilage is thicker with increased bone size, diaphysis size, and decreased femoral shaft angle. Our findings show that sexual dimorphism is strong in these first three modes, and that bone shape and cartilage thickness at the joint are strongly correlated with height but weakly correlated with mass.

Significance and Clinical Effect of Anteromedial Support Plate Assisted Reduction and Fixation in The Treatment of Complex Proximal Humeral Fractures

Background There are more and more complex consolidated proximal fractures, and the postoperative effect is not very satisfactory. Therefore, we propose a surgical method and evaluate its effect. Method A total of 77 patients with complicated proximal humeral fractures who underwent surgical treatment in the Affiliated Hospital of Nantong University from June 2015 to January 2019 were collected. Among them, the internodal groove medial support plate assisted reduction and fixation technique and the lateral locking plate were used. A total of 15 cases of complicated proximal humeral fractures were used as the study group, and 62 patients with the same type of proximal humeral fractures treated with traditional reduction methods and internal fixation with lateral locking plates during the same period were used as the control group.The operation time of the two groups; intraoperative blood loss; number of effective intraoperative fluoroscopy; postoperative humeral neck shaft angle loss after reduction; postoperative shoulder joint Constant-Murley score; upper limb function DASH score and postoperative complications were retrospectively reviewed comparative analysis. Results The number of effective intraoperative fluoroscopy was (6.18±1.869) times in the control group, more than (3.93±1.387) times in the study group, and the difference between the two was statistically significant (P<0.05);The operation time of the study group was longer than that of the control group, and the intraoperative blood loss of the study group was more than that of the control group, but the difference between the two was not statistically significant (P>0.05).In the first 1, 3, 6, and 12 months after surgery, in terms of imaging measurement, the loss angle after reduction of the humeral neck shaft angle in the control group and the study group increased with the increase in postoperative time. There was no significant difference in the lost angle after reduction of the humeral neck shaft angle between the two groups at month and 3 months (P>0.05).At the 6th and 12th months after surgery, the lost angle after reduction of the humeral neck shaft angle in the study group was smaller than that in the control group, and the difference between the two groups was statistically significant (P<0.05).For the recovery of shoulder joint function after surgery, the Constant-Murley score of the shoulder joint and the DASH score of upper limb function of the control group and the study group increased with the increase of postoperative time, while the Constant score and DASH score of the two groups were 1 after surgery. There was no significant difference at months, 3 months, 6 months and 12 months (P>0.05). Conclusion The anteromedial support plate assisted reduction of the internodal groove can be used as a single locking plate for the treatment of complex proximal humeral fractures with medial column instability. It is an option when reduction is difficult or it is difficult to maintain stable reduction, which improves the quality of reduction and reduces surgery. Loss of posterior fracture reduction.

Clinical and radiological outcome of 3- and 4-part proximal humerus fracture managed with J nails in elderly osteoporotic individuals

<p class="abstract"><strong>Background:</strong> Proximal humeral fracture is 3rd most common fracture in elderly population. Selection of appropriate implant is always challenging to get optimum results in these osteoporotic bones. Though locking plates are gold standard, major complications range from 9% to 36%. To study clinical and radiological outcome of J nail technique for Neer’s three or four part proximal humeral fractures in patients more than 60 years age.</p><p class="abstract"><strong>Methods:</strong> We retrospectively studied 60 patients of 3 or 4 part proximal humeral fractures, &gt;60 years of age treated with J nail technique from the period of 2015 to 2017. J nails were made using 2 mm 12 inches blunt tip Lambrinudi wires. At final follow-up, clinical outcome was assessed using constant score and radiological evaluation was done according to the Bahr criteria.<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean constant score at final follow-up was 90. The postoperative reduction was excellent in 98% of patients and remained excellent in 90%. The mean postoperative neck shaft angle was 135.0° and final neck shaft angle was 131.4°. No deep infection was seen. No avascular necrosis of humeral head was found till follow up to 2 years.</p><p class="abstract"><strong>Conclusions:</strong> Our study suggests that the functional and radiological outcomes obtained with J nailing are excellent and similar to locking plates and percutaneous Kirschner wire fixation with many other advantages of being simple, minimally invasive, avoiding muscle transfixation and no pin site infections.</p>

A comparative study of sex determination using femoral parameters

Introduction and Aim: Extensive examination of the femoral anthropometry has been commonly accepted to disclose sexual differentiation. The current study was carried out to evaluate various measurements of the pathologically fit femora of the unknown sex to differentiate the sex of the femora. Materials and Methods: Each femur was meticulously assessed and analyzed for six specific parameters such as maximal length, proximal breadth, and head circumference, mid-shaft circumference, vertical diameter, and neck-shaft angle of the femur bone. All the measurements were statistically analyzed and tabulated. Results:The results were highly significant to all the parameters thereby concluding that an individual’s sex can be determined by examining the femora. Conclusion:The results leave a huge scope for validation over a larger sample size focussing on an extensive human race.

Three-dimensional morphological study of the proximal femur in Crowe type IV developmental dysplasia of the hip

Background When performing femoral reconstruction in patients with Crowe type IV developmental dysplasia of the hip (DDH), anatomical deformity presents many technical challenges to orthopedic surgeons. The false acetabulum is suggested to influence load transmission and femoral development. The aim of this study was to describe the morphological features of dysplastic femurs in Crowe type IV DDH and further evaluate the potential effect of the false acetabulum on morphological features and medullary canal of Crowe type IV femurs. Methods We analyzed preoperative computed tomography scans from 45 patients with 51 hips (25 hips without false acetabulum in the IVa group and 26 hips with false acetabulum in the IVb group) who were diagnosed with Crowe type IV DDH and 30 normal hips in our hospital between January 2009 and January 2019. Three-dimensional reconstruction was performed using Mimics software, and the coronal femoral plane was determined to evaluate the following parameters: dislocation height, dislocation ratio, height of the femoral head (FH), height of the greater trochanter (GT), GT–FH height discrepancy, height of the isthmus, neck-shaft angle, femoral offset and anteversion of the femoral neck. The mediolateral (ML) width, anterolateral (AP) width and diameter of medullary canal of the proximal femur were measured on the axial sections. Further, canal flare index (CFI), metaphyseal-CFI and diaphyseal-CFI were also calculated. Results Compared with the normal femurs, the Crowe type IV DDH femurs had a higher femoral head, larger GT–FH height discrepancy, larger femoral neck anteversion, higher isthmus position and smaller femoral offset. Dislocation height and dislocation rate were significantly larger in the IVa DDH group (65.34 ± 9.83 mm vs. 52.24 ± 11.42 mm). Further, the IVb femurs had a significantly lower isthmus position, larger neck-shaft angle and smaller femoral neck anteversion than IVa femurs. The ML, AP canal widths and the diameter of medullary canal in both DDH groups were significantly smaller than the normal group. Dimensional parameters of IVa femurs were also narrower than IVb femurs in most sections, but with no difference at the level of isthmus. According to the CFIs, the variation of proximal medullary canal in IVb femurs was mainly located in the diaphyseal region, while that in IVa femurs was located in the whole proximal femur. Conclusions High dislocated femurs are associated with more anteverted femoral neck, smaller femoral offset and narrower medullary canal. Without stimulation of the false acetabulum, IVa DDH femurs were associated with higher dislocation and notably narrower medullary canal, whose variation of medullary canal was located in the whole proximal femur.

insideOut: A Bio-Inspired Machine Learning Approach to Estimating Posture in Robots Driven by Compliant Tendons

Estimates of limb posture are critical for controlling robotic systems. This is generally accomplished with angle sensors at individual joints that simplify control but can complicate mechanical design and robustness. Limb posture should be derivable from each joint's actuator shaft angle but this is problematic for compliant tendon-driven systems where (i) motors are not placed at the joints and (ii) nonlinear tendon stiffness decouples the relationship between motor and joint angles. Here we propose a novel machine learning algorithm to accurately estimate joint posture during dynamic tasks by limited training of an artificial neural network (ANN) receiving motor angles and tendon tensions, analogous to biological muscle and tendon mechanoreceptors. Simulating an inverted pendulum—antagonistically-driven by motors and nonlinearly-elastic tendons—we compare how accurately ANNs estimate joint angles when trained with different sets of non-collocated sensory information generated via random motor-babbling. Cross-validating with new movements, we find that ANNs trained with motor angles and tendon tension data predict joint angles more accurately than ANNs trained without tendon tension. Furthermore, these results are robust to changes in network/mechanical hyper-parameters. We conclude that regardless of the tendon properties, actuator behavior, or movement demands, tendon tension information invariably improves joint angle estimates from non-collocated sensory signals.