Search Results (12)

This study tackles the challenge of automatically estimating age from pelvis radiographs. Furthermore, we aim to develop a methodology for applying artificial intelligence to classify or regress medical imagery data. Our dataset comprises 684 pelvis X-ray images of patients, each accompanied by annotations and masks for various regions of interest (e.g., the femur shaft). Radiomic features, e.g., the co-occurrence matrix, were computed to characterize the image content. We assessed statistical analysis, machine learning, and deep learning methods for their effectiveness in this task. Correlation analysis indicated that using certain features in specific regions of interest is promising for accurate age estimation. Machine learning models demonstrated that when using uncorrelated features, the optimal mean absolute error (MAE) for age estimation is 5.20, whereas when employing convolutional networks on the texture feature maps yields the best result of 9.56. Automatically selecting radiomic features for machine learning models achieves a MAE of 7.99, whereas utilizing well-known convolutional architectures on the original image results in a system efficacy of 7.96. The use of artificial intelligence in medical data analysis produces comparable outcomes; however, when dealing with a large number of descriptors, selecting the most optimal ones through statistical analysis enables the identification of the best solution quickly. Full article

In a prospective study, we examined the recovery trajectory of patients with lower extremity fractures to better understand the healing process in the absence of complications. Using a chest-mounted inertial measurement unit (IMU) device for gait analysis and collecting patient-reported outcome measures, we focused on 12 key gait variables, including Mean Leg Lift Acceleration, Stance Time, and Body Orientation. We employed a linear mixed model (LMM) to analyze these variables over time, incorporating both fixed and random effects to account for individual differences and the time since injury. This model also adjusted for varying intervals between assessments. Our study provided insights into gait recovery across different fracture types using data from 318 patients who experienced no complications or readmissions during their recovery. Through LMM analysis, we found that Tibia-Distal fractures demonstrated the fastest recovery, particularly in terms of mobility and strength. Tibia-Proximal fractures showed balanced improvements in both mobility and stability, suggesting that rehabilitation should target both strength and balance. Femur fractures exhibited varied recovery, with Diaphyseal fractures showing clear improvements in stability, while Distal fractures reflected gains in limb strength but with some variability in stability. To examine patients with readmissions, we conducted a Chi-squared test of independence to determine whether there was a relationship between fracture type and readmission rates, revealing a significant association (p < 0.001). Pelvis fractures had the highest readmission rates, while Tibia-Diaphyseal and Tibia-Distal fractures were more prone to infections, highlighting the need for enhanced infection control strategies. Femur fractures showed moderate readmission and infection rates, indicating a mixed risk profile. In conclusion, our findings emphasize the importance of fracture-specific rehabilitation strategies, focusing on infection prevention and individualized treatment plans to optimize recovery outcomes. Full article

Background/Objectives: Sex estimation constitutes an important tool in the process of identifying an anonymous individual in forensic contexts. The bones commonly used in sex estimation are those that exhibit greater sexual dimorphism, such as the pelvis or the femur. However, these bones are not always available, which means that it is necessary to find alternative bones for analysis. The main purposes of this study include the assessment of fibular and tibial sexual dimorphism in samples from three Portuguese reference skeletal collections, and the development of metric models for the estimation of biological sex. Methods: A sample of 290 individuals (160 females; 130 males), belonging to the Coimbra Identified Skeletal Collection (training sample), the Lisbon Identified Skeletal Collection (test sample), and 21st the Century Identified Skeletal Collection (training sample), was employed to develop models for sex prediction through logistic regression. Results: From the identification of the most dimorphic bone dimensions, 13 models were created with an accuracy ranging between 80.1% and 89.7% in the training sample (under cross-validation), and between 82.5% and 91.7% in the test sample Conclusions: The results of this work show that predictive models based on the fibula and tibia can be accurate and unbiased. Full article

This study investigates the morphological impact of using three-dimensional (3D) printed custom implants in surgical hip reconstruction compared to the conventional bone graft and standard size implant methods. An amount of 16 patients at the Rizzoli Orthopaedic Institute who underwent hip reconstruction surgery for tumors involving the P2 pelvis region were selected using stratified sampling. Half of them were randomly selected to receive 3D-printed implants, and the other half were selected to receive standard implants with bone grafts. Six months post-surgery, computed tomography (CT) scans were used to identify the hip joint center of rotation and to measure greater the trochanter offset and acetabular inclination angle. These CT scans were also used to construct a 3D model of the pelvis for 3D measurements. The results show no significant differences in accuracy, using Student’s t-test and Mann–Whitney U-test (p-value > 0.05), between the two methods for reconstructing the hip joint center of rotation or greater trochanter offset. However, 3D-printed implants showed statistically significant greater precision, using Student’s t-test (p-value < 0.05), in reconstructing the acetabular inclination angle compared to the conventional bone graft and standard-sized off-the-shelf implants. This superior precision reduces the risk of impingement of the femur implant neck with the acetabulum implant cup, which directly relates to improved implant survivorship. These findings support the continued exploration of 3D printing technology for personalized orthopedic solutions. Full article

Background: Our study addresses the lack of consensus on measuring leg length discrepancy (LLD) after total hip arthroplasty (THA). We will assess the inter-observer variability and correlation between the five most commonly used LLD methods and investigate the use of trigonometric principles in overcoming the limitations of current techniques. Methods: LLD was measured on postoperative AP pelvic radiographs using five conventional methods. CT images created a 3D computer model of the pelvis and femur. The resulting models were projected onto a 2D, used to measure LLD by the five methods. The measurements were evaluated via Taguchi analysis, a statistical method identifying the process’s most influential factors. The approach was used to assess the new trigonometric method. Results: Conventional methods demonstrated poor correlation. Methods referenced to the centers of the femoral heads were insensitive to LLD originating outside the acetabular cup. Methods referencing either the inter-ischial line or the inter-obturator foramina to the lesser trochanter were sensitive to acetabular and femoral components. Trigonometry-based measurements showed a higher correlation. Conclusions: Our results underscore clinicians’ need to specify the methods used to assess LLD. Applying trigonometric principles was shown to be accurate and reliable, but it was contingent on proper radiographic alignment. Full article

The reverse engineering (RE) process is often necessary in today’s engineering and medical industries. Expertise in measurement technology, data processing, and CAD modeling is required to ensure accurate reconstruction of an object’s geometry. However, errors are generated at every stage of geometric reconstruction, affecting the dimensional and geometric accuracy of the final 3D-CAD model. In this article, the geometry of reconstructed models was measured using contact and optical methods. The measurement data representing 2D profiles, 3D point clouds, and 2D images acquired in the reconstruction process were saved to a stereolithography (STL) model. The reconstructed models were then subjected to a CAD modeling process, and the accuracy of the parametric modeling was evaluated by comparing the 3D-CAD model to the 3D-STL model. Based on the results, the model used for clamping and positioning parts to perform the machining process and the connecting rod provided the most accurate mapping errors. These models represented deviations within ±0.02 mm and ±0.05 mm. The accuracy of CAD modeling for the turbine blade model and the pelvis part was comparable, presenting deviations within ±0.1 mm. However, the helical gear and the femur models showed the highest deviations of about ±0.2 mm. The procedures presented in the article specify the methods and resolution of the measurement systems and suggest CAD modeling strategies to minimize reconstruction errors. These results can be used as a starting point for further tests to optimize CAD modeling procedures based on the obtained measurement data. Full article

Background Context: Pelvic ring fractures are becoming more common in the aging population and can prove to be fatal, having mortality rates between 10% and 16%. Stabilization of these fractures is challenging and often require immediate internal fixation. Therefore, it is necessary to have a biomechanical understanding of the different fixation techniques for pelvic ring fractures. Methods: A previously validated three-dimensional finite element model of the lumbar spine, pelvis, and femur was used for this study. A unilateral pelvic ring fracture was simulated by resecting the left side of the sacrum and pelvis. Five different fixation techniques were used to stabilize the fracture. A compressive follower load and pure moment was applied to compare different biomechanical parameters including range of motion (contralateral sacroiliac joint, L1-S1 segment, L5-S1 segment), and stresses (L5-S1 nucleus stresses, instrument stresses) between different fixation techniques. Results: Trans-iliac–trans-sacral screw fixation at S1 and S2 showed the highest stabilization for horizontal and vertical displacement at the sacral fracture site and reduction of contralateral sacroiliac joint for bending and flexion range of motion by 165% and 121%, respectively. DTSF (Double transiliac rod and screw fixation) model showed highest stabilization in horizontal displacement at the pubic rami fracture site, while the L5_PF_W_CC (L5-Ilium posterior screw fixation with cross connectors) and L5_PF_WO_CC (L5-Ilium posterior screw fixation without cross connectors) showed higher rod stresses, reduced L1-S1 (approximately 28%), and L5-S1 (approximately 90%) range of motion. Conclusions: Longer sacral screw fixations were superior in stabilizing sacral and contralateral sacroiliac joint range of motion. Lumbopelvic fixations displayed a higher degree of stabilization in the horizontal displacement compared to vertical displacement of pubic rami fracture, while also indicating the highest rod stresses. When determining the surgical approach for pelvic ring fractures, patient-specific factors should be accounted for to weigh the advantages and disadvantages for each technique. Full article

Background/Objectives: Global femoral offset (GFO) and leg length discrepancy (LLD) affect outcomes after total hip arthroplasty (THA). Moreover, the sum of the difference in GFO between the THA and non-surgical sides and LLD (SGL) reportedly affects the outcomes in a two-dimensional evaluation. We examined the association of the GFO, LLD, and SGL with the Harris Hip Score (HHS) using a three-dimensional (3D) evaluation. Methods: We retrospectively surveyed 172 patients with hemilateral hip osteoarthritis who underwent THA. The GFO, LLD, and SGL were measured using the 3D pelvis and femur models; these models were adjusted for the pelvis and femur, and the coordinate systems were parallelized. Furthermore, their relationship with the modified HHS (mHHS) 1 year after THA was determined. Results: Significant correlations were found among mHHS, GFO, and SGL in the binomial group, whereas LLD was not significantly correlated. The optimal values of GFO and SGL were 1.01 mm and 0.18 mm/100 cm body height, respectively, which were considered optimal when the SGL values were approximately equal to those of the non-operative side. The optimal ranges for GFO and SGL were −1.65 to 3.67 mm and −4.78 to 5.14 mm/100 cm, respectively. Conclusions: Our findings were obtained after adjusting the pelvis and femur to a unified coordinate system. Therefore, the results of this study can be directly applied to 3D planning. Full article

Late-discovered developmental hip dysplasia deformities often necessitate complex surgical treatments and meticulous preoperative planning. The selection of osteotomies is contingent upon the patient’s age and the specific structural deformity of the hip. In our anatomical hip model, derived from the data of a 12-year-old patient, we performed virtual osteotomies that are commonly recommended for such cases. We precisely constructed geometric models for various osteotomies, including the Dega, Pemberton, Tönnis, Ganz, Chiari pelvic, and Pauwels femoral osteotomies. We employed Autodesk Inventor for the finite element analysis of the hip joint and the corrective osteotomies. In comparing one-stage osteotomies, we noted that the Dega and Ganz pelvic osteotomies, especially when combined with the Pauwels femoral osteotomy, yielded the most favorable outcomes. These combinations led to enhanced femoral head coverage and reduced intra-articular pressure. Furthermore, we calculated the femoral head-to-acetabulum volume ratio for both the Dega and Pauwels osteotomies. The encouraging results we obtained advocate for the integration of finite element analysis in virtual osteotomies of the pelvis and femur as a preoperative tool in the management of developmental hip dysplasia. Full article

In this study, a human hip joint with Cam-type Femoroacetabular Impingement (FAI) is studied by the Finite Element Method (FEM). This pathology consists of a malformation that causes a lack of sphericity of the head of the femur. In turn, this causes wear and tear of the cartilage, a cause of early osteoarthritis of the hip. The objective is to use the FEM to analyze and compare the increase in the von Mises stress and displacement of the cartilage in healthy and damaged (with Cam-type) human hip joints that this syndrome affects. The 3D models were reconstructed from two medical CT scans of a healthy and a damaged hip joint that were obtained, five years apart, for a male of 80 kg in weight. The 3D models were reconstructed using 3D Slicer software. The cortical and trabecular bone, as well as the cartilage, were segmented. The defects were corrected by MesMixer software that generated STL files. Both models were imported into the Marc Mentat^® software for the Finite Element Analysis (FEA). It was noted that the thickness of the cartilage decreased enormously during the five years, which suggests imminent mechanical contact between the head of the femur and the acetabulum of the pelvis. The FEA results showed an excessive increase in the stress and displacement of the cartilage. This will certainly result in a condition of osteoarthritis for the patient in the future years. Full article

Roentgen stereophotogrammetric analysis (RSA) is the gold standard to detect in vivo material wear of the bearing couples in hip arthroplasty. Some surgical planning tools offer the opportunity to detect wear by using standard a.p. radiographs (2D_wear), whilst RSA (3D_wear) needs a special radiological setup. The aims of this study are to prove the interchangeable applicability of a 2D_wear approach next to RSA and to assess the influence of different pelvic positions on measurement outcomes. An implant-bone model was used to mimic three different wear scenarios in seven pelvic-femur alignment positions. RSA and a.p. radiographs of the reference and a follow-up (simulated wear) pose were acquired. Accuracy and precision were worse for the 2D_wear approach (0.206 mm; 0.159 mm) in comparison to the 3D_wear approach (0.043 mm; 0.017 mm). Changing the pelvic position significantly influenced the 2D_wear results (4 of 7, p < 0.05), whilst 3D_wear results showed almost no change. The 3D_wear is superior to the 2D_wear approach, as it is less susceptible to changes in pelvic position. However, the results suggest that a 2D_wear approach may be an alternative method if the wear present is in the range of 100–500 µm and a.p. radiographs are available with the pelvis projected in a neutral position. Full article

The prediction of bone remodeling behaviour is a challenging factor in encouraging the long-term stability of hip arthroplasties. The presence of femoral components modifies the biomechanical environment of the bone and alters the bone growth process. Issues of bone loss and gait instability on both limbs are associated with the remodeling process. In this study, finite element analysis with an adaptive bone remodeling algorithm was used to predict the changes in bone mineral density following total hip and resurfacing hip arthroplasty. A three-dimensional model of the pelvis–femur was constructed from computed tomography (CT-based) images of a 79-year-old female patient with hip osteoarthritis. The prosthesis stem of the total hip arthroplasty was modelled with a titanium alloy material, while the femoral head had alumina properties. Meanwhile, resurfacing of the hip implant was completed with a cobalt-chromium material. Contact between the components and bone was designed to be perfectly bonded at the interface. Results indicate that the bone mineral density was modified over five years on all models, including hip osteoarthritis. The changes of BMD were predicted as being high between year zero and year one, especially in the proximal region. Changes were observed to be minimal in the following years. The bone remodeling process was also predicted for the non-operated femur. However, the adaptation was lower compared to the operated limbs. The reduction in bone mineral density suggested the bone loss phenomenon after a few years. Full article