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Background: Proximal humerus fractures are common in adults aged 65 and older and provide challenges for osteoporotic patients due to the risk of suboptimal fixation and complications. Locking plates are often utilized to treat two-part fractures; however, ongoing concerns about their stability exist. This pilot study investigates the biomechanical impact of subchondral locking screws compared to unicortical screws in osteoporotic two-part cadaveric proximal humerus fractures. Methods: Using dual-energy X-ray absorptiometry (DXA), cadaveric shoulder specimens from eight female Caucasian donors with comparable bone mineral densities were used for the study. Either unicortical or bicortical locking screws (the latter representing subchondral screws in real surgeries) were utilized to fix locking plates. Axial load to failure and cyclic physiologic abduction moments were applied in biomechanical testing. Findings: The study found no statistically significant difference in interfragmentary displacement between the unicortical and bicortical groups (p = 0.78). The mechanical properties of both groups were found to be comparable in terms of yield (p = 0.59), ultimate (p = 0.86), and fracture strengths (p = 0.70). Furthermore, rigidity analysis did not identify any significant difference between the two groups (p = 0.22). Interpretation: Our findings indicate that there is little to no difference in the stability of the construct for osteoporotic two-part proximal humerus fractures, in contrast to general recommendations against unicortical screws. This pilot study suggests that the choice between unicortical and subchondral locking screws may not significantly affect biomechanical characteristics in osteoporotic two-part proximal humerus fractures, despite the study's limitations.

IntroductionOver 6.8 million fractures occur annually in the US, with 10% experiencing delayed- or non-union. Anabolic therapeutics like PTH analogs stimulate fracture repair, and small molecule salt inducible kinase (SIK) inhibitors mimic PTH action. This study tests whether the SIK inhibitor YKL-05-099 accelerates fracture callus osteogenesis.Methods126 female mice underwent femoral shaft pinning and midshaft fracture, receiving daily injections of PBS, YKL-05-099, or PTH. Callus tissues were analyzed via RT-qPCR, histology, single-cell RNA-seq, and μCT imaging. Biomechanical testing evaluated tissue rigidity. A hydrogel-based delivery system for PTH and siRNAs targeting SIK2/SIK3 was developed and tested.ResultsYKL-05-099 and PTH-treated mice showed higher mineralized callus volume fraction and improved structural rigidity. RNA-seq indicated YKL-05-099 increased osteoblast subsets and reduced chondrocyte precursors. Hydrogel-released siRNAs maintained target knockdown, accelerating callus mineralization.DiscussionYKL-05-099 enhances fracture repair, supporting selective SIK inhibitors’ development for clinical use. Hydrogel-based siRNA delivery offers targeted localized treatment at fracture sites.

Abstract Hip fractures exceed 250,000 cases annually in the United States, with the worldwide incidence projected to increase by 240–310% by 2050. Hip fractures are predominantly diagnosed by radiologist review of radiographs. In this study, we developed a deep learning model by extending the VarifocalNet Feature Pyramid Network (FPN) for detection and localization of proximal femur fractures from plain radiography with clinically relevant metrics. We used a dataset of 823 hip radiographs of 150 subjects with proximal femur fractures and 362 controls to develop and evaluate the deep learning model. Our model attained 0.94 specificity and 0.95 sensitivity in fracture detection over the diverse imaging dataset. We compared the performance of our model against five benchmark FPN models, demonstrating 6–14% sensitivity and 1–9% accuracy improvement. In addition, we demonstrated that our model outperforms a state-of-the-art transformer model based on DINO network by 17% sensitivity and 5% accuracy, while taking half the time on average to process a radiograph. The developed model can aid radiologists and support on-premise integration with hospital cloud services to enable automatic, opportunistic screening for hip fractures.

Hip fractures inflict heightened morbidity and mortality upon older adults. Although previous studies have explored the impact of individual demographic factors on hip fracture risk, a comprehensive review can help reconcile disparities among these factors. This meta-analysis encompassed 69 studies involving 976,677 participants and 99,298 cases of hip fractures. We found that age ≥ 85 (OR = 1.75), BMI < 18.5 (OR 1.72), female sex (OR = 1.23), history of falls (OR = 1.88), previous fractures (OR = 3.16), menopause (OR 7.21), history of maternal hip fractures (OR = 1.61), single and unmarried status (OR = 1.70), divorced status (OR 1.38), residing in a residential care facility (OR = 5.30), and living alone (OR = 1.47) were significantly associated with an increased incidence of hip fracture. Conversely, BMI ranging from 25 to 30 (OR = 0.59), BMI > 30 (OR = 0.38), parity (OR = 0.79), non-Caucasian descent (overall OR = 0.4, Asian OR 0.36, Black OR = 0.39, and Hispanic OR = 0.45), and rural residence (OR = 0.95) were significantly associated with a diminished risk of hip fracture. Hip fracture patients exhibited significantly lower weight and BMI than the non-fracture group, while their age was significantly higher. However, age at menopause and height did not significantly differ between the two groups.

Abstract Background Anterior cruciate ligament (ACL) rupture is a common orthopedic injury, occurring in roughly 68.6 per 100,000 persons annually, with the primary treatment option being ACL reconstruction. However, debate remains about the appropriate graft type for restoring the native biomechanical properties of the knee. Furthermore, plastic graft elongation may promote increased knee laxity and instability without rupture. This study aims to investigate the plastic properties of common ACL-R graft options. Methods Patellar tendon (PT), hamstring tendon (HT), and quadriceps tendon (QT) grafts were harvested from 11 cadaveric knees (6 male and 5 female) with a mean age of 71(range 55–81). All grafts were mechanically tested under uniaxial tension until failure to determine each graft’s elastic and plastic biomechanical properties. Results Mechanically, the QT graft was the weakest, exhibiting the lowest failure force and the lowest failure stress (QT QT, p = 0.0002) and Young’s modulus (PT > QT, p = 0.001; PT > HT, p = 0.041). The HT graft had the highest plastic elongation at 4.01 ± 1.32 mm (HT > PT, p = 0.002). The post-yield behavior of the HT tendon shows increased energy storage capabilities with the highest plastic energy storage (HT > QT, p = 0.012) and the highest toughness (HT > QT, p = 0.032). Conclusion Our study agrees with prior studies indicating that the failure load of all grafts is above the requirements for everyday activities. However, grafts may be susceptible to yielding before failure during daily activities. This may result in the eventual loss of functionality for the neo-ACL, resulting in increased knee laxity and instability.

Abstract Background Substance administration to laboratory animals necessitates careful consideration and planning in order to enhance agent distribution while reducing any harmful effects from the technique. There are numerous methods for administering cannabinoids; however, several parameters must be considered, including delivery frequency, volume of administration, vehicle, and the level of competence required for staff to use these routes properly. There is a scarcity of information about the appropriate delivery method for cannabinoids in animal research, particularly those that need the least amount of animal manipulation during the course of the investigation. This study aims to assess the feasibility and potential side effects of intraperitoneal and subcutaneous injection of CBD and THC using propylene glycol or Kolliphor in animal models. By evaluating the ease of use and histopathological side effects of these solvents, this study intends to help researchers better understand an accessible long-term delivery route of administration in animal experiments while minimizing the potential confounding effects of the delivery method on the animal. Methods Intraperitoneal and subcutaneous methods of systemic cannabis administration were tested in rat models. Subcutaneous delivery via needle injection and continuous osmotic pump release were evaluated using propylene glycol or Kolliphor solvents. In addition, the use of a needle injection and a propylene glycol solvent for intraperitoneal (IP) administration was investigated. Skin histopathological changes were evaluated following a trial of subcutaneous injections of cannabinoids utilizing propylene glycol solvent. Discussion Although IP delivery of cannabinoids with propylene glycol as solvent is a viable method and is preferable to oral treatment in order to reduce gastrointestinal tract degradation, it has substantial feasibility limitations. We conclude that subcutaneous delivery utilizing osmotic pumps with Kolliphor as a solvent provides viable and consistent route of administration for long-term systemic cannabinoid delivery in the preclinical context.

Purpose: To determine the overall incidence of venous thromboembolism (VTE) following shoulder arthroscopy and to define potential risk factors associated with its development that may help define guidelines for the use of thromboprophylaxis. Methods: A systematic review was performed using PubMed, Embase, Web of Science, CINAHL, and Cochrane databases per PRISMA guidelines. The search terms consisted of variations of ''Venous Thromboembolism'' and ''Shoulder Arthroscopy.'' Information regarding arthroscopy indication, risk factors, outcomes, and patient demographics was recorded and analyzed, and pooled odds ratios were reported for each variable. Results: Six hundred eighty-five articles were identified in the initial search, and 35 articles reported DVT, PE, or VTE incidence following shoulder arthroscopy. Seventeen nonoverlapping articles with a unique patient population incidence rates. Four articles were then used for subgroup meta-analysis. The incidence rate of VTE was 0.24%, ranging from 0.01% to 5.7%. BMI >30 (OR = 1.46; 95% CI = [1.22, 1.74]; I2 = 0%) and hypertension (OR = 1.64; 95% CI = [1.03, 2.6]; I2 = 75%) were significant risk factors (P < .05) for developing VTE following shoulder arthroscopy. Diabetes (OR = 1.2; 95% CI = [0.97, 1.48]; I2 = 0%), insulin-dependent diabetes (OR = 5.58; 95% CI = [0.12, 260.19]; I2 = 85%), smoking (OR = 1.04; 95% CI = [0.79, 1.37]; I2 = 12%), male sex (OR = 0.95; 95% CI = [0.49, 1.85]; I2 = 86%) and age over 65 (OR = 4.3; 95% CI = [0.25, 72.83]; I2 = 85%) were not associated with higher VTE risk. Conclusions: The VTE incidence following shoulder arthroscopy is low at 0.24%. Patients with BMI >30 and hypertension are at a higher risk for VTE after shoulder arthroscopy. Level of Evidence: Level IV, systematic review and meta-analysis of Level I-IV studies.

Study Design Single-center retrospective cohort. Purpose To compare surgical outcomes of patients based on lumbar drain variables relating to output and duration. Overview of Literature The use of drains following lumbar spine surgery, specifically with respect to hospital readmission, postoperative hematoma, postoperative anemia, and surgical site infections, has been controversial. Methods Patients aged ≥18 years who underwent lumbar fusion with a postoperative drain between 2017 and 2020 were included and grouped based on hospital readmission status, last 8-hour drain output (

Abstract Background The current understanding of glenohumeral joint stability is defined by active restrictions and passive stabilizers including naturally-occurring negative intraarticular pressure. Cadaveric specimens have been used to evaluate the role of intraarticular pressure on joint stability, although, while the shoulder’s negative intraarticular pressure is universally acknowledged, it has been inconsistently accounted for. Hypothesis During continuous, passive humeral abduction, releasing the native intraarticular pressure increases joint translation, and restoring this pressure decreases joint translations. Study design Descriptive Laboratory Study. Methods A validated shoulder testing system was used to passively abduct the humerus in the scapular plane and measure joint translations for seven (n = 7) cadaveric specimens. The pressure within the glenohumeral joint was measured via a 25-gauge needle during passive abduction of the arm, which was released and subsequently restored. During motion, the rotator cuff muscles were loaded using stepper motors in a force feedback loop and electromagnetic sensors were used to continuously measure the position of the humerus and scapula. Joint translation was defined according to the instant center of rotation of the glenohumeral head according to the recommendations by the International Society of Biomechanics. Results Area under the translation versus abduction angle curve suggests that releasing the pressure within the capsule results in significantly less posterior translation of the glenohumeral head as compared to intact (85–90˚, p

Abstract Objective Medial patellofemoral ligament (MPFL) injury occurs in the majority of the cases of acute patellar dislocation. The role of concomitant lateral retinaculum release with MPFL reconstruction is not clearly understood. Even though the lateral retinaculum plays a role in both medial and lateral patellofemoral joint stability in MPFL intact knees, studies have shown mixed clinical outcomes following its release during MPFL reconstruction surgery. Better understanding of the biomechanical effects of the release of the lateral retinaculum during MPFL reconstruction is warranted. We hypothesize that performing a lateral release concurrent with MPFL reconstruction will disrupt the patellofemoral joint biomechanics and result in lateral patellar instability. Methods A previously developed and validated finite element (FE) model of the patellofemoral joint was used to understand the effect of lateral retinaculum release following MPFL reconstruction. Contact pressure (CP), contact area (CA) and lateral patellar displacement were recorded. abstract. Results FE modeling and analysis demonstrated that lateral retinacular release following MPFL reconstruction with tibial tuberosity-tibial groove distance (TT-TG) of 12 mm resulted in a 39% decrease in CP, 44% decrease in CA and a 20% increase in lateral patellar displacement when compared to a knee with an intact MPFL. In addition, there was a 45% decrease in CP, 44% decrease in CA and a 21% increase in lateral displacement when compared to a knee that only had an MPFL reconstruction. Conclusion This FE-based analysis exhibits that concomitant lateral retinaculum release with MPFL reconstruction results in decreased PF CA, CP and increased lateral patellar displacement with increased knee flexion, which may increase the risk of patellar instability.