Search

Introduction: The lesser trochanter profile (LTP) method is an intraoperative fluoroscopic technique that can assess the femoral version and limit malrotation. The purpose of this study was to directly assess the accuracy and reliability of the LTP method, as well as determine the incidence of malrotation produced by this technique. Methods: Three groups of observers (fellowship-trained orthopedic surgeons, orthopedic residents, and medical students) utilized the LTP method to replicate pre-imaged rotation angles on a cadaveric femur bone. Recorded outcomes include rotational error and number of attempts. Accuracy and interobserver reliability were assessed by rotational error and the interclass correlation coefficient (ICC), respectively. Results: Accuracy was within 3° for all three groups. ICC between each group was greater than 0.99. There was no statistical difference between the accuracy of fellowship-trained surgeons, orthopedic residents, and medical students. Medical students on average required more attempts to obtain their final image compared to fellowship-trained surgeons. There was no statistical difference in the number of attempts between residents and fellowship-trained surgeons. Conclusion: None of the LTP measurements were greater than 15°, the clinical threshold for malrotation. The average error of the observers was less than 3°, demonstrating that the LTP is an effective method of assessing the femoral version. There was no statistically significant difference between the observers, indicating that this technique is reliable and easy to use. Ultimately, the LTP method is easily reproducible for surgeons to avoid femoral malrotation.

The development of next-generation polymers necessitates optimizing several key properties simultaneously, a task that is expensive and infeasible using traditional trial-and-error experimental approaches. A promising alternative is employing a combination of machine learning and physics-based tools to rapidly screen the polymer design space and provide suggestions of new polymers that meet the critical properties required for industrial applications. In this study, we introduce a comprehensive workflow that utilizes machine learning and molecular modeling approaches to design new polymers with the focus on improving five polymer properties: (1) glass transition temperature, (2) dielectric constant, (3) refractive index, (4) stress optic coefficient, and (5) linear coefficient of thermal expansion. Using a small dataset ( $ \lt$ 200 unique polymers), we developed quantitative structure-property relationships (QSPRs) models to accurately predict the experimental polymer properties for both homo- and co-polymer systems. We tested several ML algorithms and identified the best models for predicting these polymer properties, achieving test set R ^2 greater than 0.77 across all properties. We then explored new polymers by creating a library of over ∼10 000 homopolymers using R-group enumeration tools and applied the trained QSPR models to rapidly predict the five polymer properties. The predictions of QSPR models were used to create a multi-parameter optimization score, which helped downselect the large polymer space to ∼10 promising candidates. The properties of these selected polymer candidates were subsequently validated with classical molecular dynamics simulations and density functional theory, revealing a strong correlation with the QSPR model predictions. Finally, one of the top candidates was validated by experiments, which showed good agreement against QSPR and physics-based models. Our workflow underscores the power of combining data-driven and theoretical methods in the polymer design process given a small dataset size, offering a valuable resource for experimentalists looking to leverage computer-aided strategies in materials innovation.

Introduction: The purpose of this study is to report on infection with anterior subcutaneous internal pelvic fixation (INFIX) for pelvic ring injuries and the outcomes of treatment. Methods: An IRB-approved retrospective study was performed using trauma databases of a level one and level two trauma center from 2012–2018. Infection after the INFIX procedure was diagnosed in 10 of 179 cases. Treatment included formal irrigation and debridement, removal of the hardware, and culture-specific antibiotics. Patients were followed for a minimum of 12 months. Recorded outcomes include X-rays, Majeed scores, and the presence of any loss of reduction using reduction parameters. Results: Time to detect the infection was 54.2 ± 24.3 days (range 24–90, median 56 days). Staphylococcus aureus was the most common bacteria isolated. The average follow-up was 830 ± 170 days (range 575–1088 days). All patients went on to the radiographic union. There were no recurrent infections or osteomyelitis at the latest follow-up. Patients maintained their reduction after INFIX removal (KI), and Majeed scores ranged from 72 to 96 (seven good, three excellent). Discussion: Infections after using the INFIX procedure were dealt with by irrigating and debriding the wounds, removing the INFIX with culture-specific antibiotics for 2–6 weeks. Implants were maintained for at least 25 days, and there was no loss of reduction. There were no long-term sequelae noted in this small series or the literature review included in this paper.

The placement of anterior column screws is a useful procedure and has standard views when placing this screw in the supine position. Feng et al. described an acetabular anterior column axial view for patients in the supine position for a placement of a retrograde anterior column screw [J Orthop Surg (Hong Kong) 25, 2309499016685012]. However, many acetabular fracture surgeries are performed in the lateral decubitus position due to a variety of reasons. Placing an antegrade anterior column screw in this position is difficult due to an unfamiliarity of the optimal fluoroscopic images. The purpose of this article is to describe a novel technique to obtain appropriate imaging to safely place an anterior column screw while the patient is in the lateral decubitus position.

Introduction: Locked intramedullary nailing (IMN) is the standard treatment for femoral shaft fractures in adults with high rates of union and relatively low rates of complications. Leg length discrepancy (LLD) after IMN of femoral shaft fractures is common, and is reported in 20–43% of cases. A known surgical challenge when trying to obtain equal leg lengths is comminuted fracture, which results in a loss of bony landmarks that guide reduction. The purpose of this study was to assess the effect of inherent tibial asymmetry on LLD measurements after IMN. Methods: Postoperative CT scanograms were performed on 79 consecutive patients after locked IMN for comminuted femoral shaft fracture. Leg lengths were determined by measurements taken from the scout view of a CT scanogram. Calculations of discrepancy were made for both femurs, tibias, and total leg length. Assessment was also made on the frequency wherein the tibial discrepancy compounded the femoral discrepancy. In situations where a limb segment was exactly symmetric to the contralateral side, the total leg was not regarded as a having compounded asymmetry. Results: Notable discrepancies were found in tibial length that significantly departed from the null of symmetry (p < 0.0001). Forty-two patients (53.2%) were found to have a tibial asymmetry of 3 mm or more, and 20 patients (25.3%) were found to exhibit a difference of 6.3 mm or more. Median femoral discrepancy was 5.3 mm and median tibial discrepancy was 3.0 mm. Seven patients were found to be asymmetric in total leg length as a consequence of underlying tibial asymmetry. Conversely, 11 patients benefited from their tibial asymmetry, which compensated for femoral asymmetry after IMN. Conclusion: Tibial symmetry cannot be assumed. If not accounted for, inherent tibial asymmetry may influence LLD after IMN of femur fractures.

Abstract Background We have recently developed a subcutaneous anterior pelvic fixation technique (INFIX). This internal fixator permits patients to sit, roll over in bed and lie on their sides without the cumbersome external appliances or their complications. The purpose of this study was to evaluate the biomechanical stability of this novel supraacetabular pedicle screw internal fixation construct (INFIX) and compare it to standard internal fixation and external fixation techniques in a single stance pelvic fracture model. Methods Nine synthetic pelves with a simulated anterior posterior compression type III injury were placed into three groups (External Fixator, INFIX and Internal Fixation). Displacement, total axial stiffness, and the stiffness at the pubic symphysis and SI joint were calculated. Displacement and stiffness were compared by ANOVA with a Bonferroni adjustment for multiple comparisons Results The mean displacement at the pubic symphysis was 20, 9 and 0.8 mm for external fixation, INFIX and internal fixation, respectively. Plate fixation was significantly stiffer than the INFIX and external Fixator (P = 0.01) at the symphysis pubis. The INFIX device was significantly stiffer than external fixation (P = 0.017) at the symphysis pubis. There was no significant difference in SI joint displacement between any of the groups. Conclusions Anterior plate fixation is stiffer than both the INFIX and external fixation in single stance pelvic fracture model. The INFIX was stiffer than external fixation for both overall axial stiffness, and stiffness at the pubic symphysis. Combined with the presumed benefit of minimizing the complications associated with external fixation, the INFIX may be a more preferable option for temporary anterior pelvic fixation in situations where external fixation may have otherwise been used.