Comparing the Immune Response to PEEK as an Implant Material with and without P-15 Peptide as Bone Graft Material in a Rabbit Long Bone Model.

P-15 is a 15-amino-acid-long biomimetic peptide widely demonstrated to enhance osteogenesis in vivo. Despite the prevalence of polyether-ether-ketone (PEEK) in interbody device manufacturing, a growing body of evidence suggests it may produce an unfavorable immune response. The purpose of this preliminary study was to characterize the immune response and new bone growth surrounding PEEK implants with and without a P-15 peptide-based osteobiologic. A bilateral femoral defect model was conducted using New Zealand white rabbits. A total of 17 test subjects received one implant in each distal femur, either with or without bone graft material. Animals were allowed to survive to 4 or 8 weeks, at which time the femurs were collected and subjected to micro-computer tomography (microCT) or cytokine analysis. MicroCT analysis included the quantification of bone growth and density surrounding each implant. The cytokine analysis of periprosthetic tissue homogenates included the quantification of interleukins (ILs) and TNF-α expression via ELISA kits. Improvements in bone volume were observed in the P-15 cohort for the regions of interest, 500-136 and 136-0 µm from the implant surface, at 8 weeks post-op. Concentrations of IL-1ß, IL-4, and IL-6 cytokines were significantly higher in the P-15 cohort compared to the PEEK cohort at the 4-week timepoint. Significant reductions in the concentrations of IL-4 and IL-6 cytokines from the 4- to 8-week cohort were observed in the P-15 cohort only. The P-15 peptide has the potential to modulate the immune response to implanted materials. We observed improvements in bone growth and a more active micro-environment in the P-15 cohort relative to the PEEK control. This may indicate an earlier transition from the inflammatory to remodeling phase of healing.

Association of sociodemographic characteristics with the timeliness of surgery for patients with open tibial fractures.

BACKGROUND: The American College of Surgeons recommends operative debridement of open tibial fractures within 24 h of presentation. It is unknown what the compliance rates are with this recommendation and what factors contribute to delays to operation. METHODS: To determine the characteristics associated with delays to operation for open tibial fractures, we conducted a retrospective cohort study utilizing American College of Surgeons Trauma Quality Improvement Program data from 2017 to 2021. Individuals aged 18 and older presenting to a trauma center with an open tibial fracture were included. Associations were determined with a hierarchal regression model nesting patients within facilities. RESULTS: Of the 24,102 patients presenting to 491 trauma centers, 66.3 % identified as White, 21.7 % as Black, 1.5 % as Asian, 1.1 % as American Indian, and 10.6 % as Other race. In total, 15.8 % identified as Hispanic. Patients were most often men (75.9 %) and privately insured (47.6 %). The median time to OR was 10.2 h (IQR 4.4-17.7) with 84.6 % receiving surgery within 24 h. In adjusted analyses, Black and American Indian patients had 5.5 % (CI 1.3 %-9.9 %) and 17.8 % (CI 2.2 %-35.8 %) longer wait times, respectively, and a decreased odds of receiving surgery within 24 h (AOR 0.85, CI 0.8-0.9; AOR 0.69, CI 0.5-0.9) when compared to White patients. Female patients had 6.5 % (CI 3.0 %-10.2 %) longer wait times than men. Patients with Medicaid had 5.5 % (CI 1.2 %-9.9 %) longer wait times than those with private insurance. Greater time to OR was associated with increasing age (p < 0.001), increasing injury severity (p < 0.001), and the presence of altered mentation (p < 0.001). CONCLUSION: We identified longer wait times to operative irrigation and debridement of open tibial fractures for Black and American Indian patients, women, and those with Medicaid. The implementation of health equity focused quality metrics may be necessary to achieve equity in trauma care.

Closed reduction by robot with different modes: Experimental study on tibial fracture specimen.

PURPOSE: This paper evaluates the accuracy and safety of a long bone fracture reduction robot under different surgical modes. METHODS: A long bone fracture reduction robot system was developed, which can be controlled via an autonomous surgical mode or a master-slave surgical mode. Reduction experiments were conducted on a long bone cadaver specimen. The accuracy and safety of the robotic reduction were compared across the different surgical modes. RESULTS: When the fracture reduction was completed by the robot, the translational deviation was less than 2 mm, and the angular deviation was less than 3° The autonomous reduction time was 140 s, while the master-slave reduction time was 200 s. CONCLUSIONS: Based on CT imaging verification, the accuracy of the robot in both autonomous and master-slave surgical modes meets clinical requirements. Future work will focus on further optimizing the robot system.

Percutaneous injection of autologous platelet gel accelerate healing in diabetic tibial non union: On going longitudinal study.

INTRODUCTION: In this study the tibial shaft fracture non unions in diabetes mellitus are evaluated with percutaneous autologous platelet gel supplementation to accelerate union are compared with individually matched control group with autologous iliac crest bone marrow aspirate injection. MATERIAL AND METHODS: This present study was carried out on tibial non unions in diabetic patients recruited in an ongoing longitudinal study over a period of 2006 to 2017, treated by one surgeon at one institute, are included in this report. Each of 18 established tibial atrophic, aseptic non unions treated by percutaneous autologous platelets and iliac crest bone marrow aspirate were followed up on regular basis up till 9 months. The healing of non union was assessed clinically by painless full weight bearing and the radiological union was judged by bridging callus formation observed on at least 3 of 4 cortices in anteroposterior and lateral views. RESULTS: Union was observed in 17 (94.4 %) patients of the autologous platelet group. The average time to union was 9.2 weeks (range 8 to 18 weeks) after percutaneous autologous platelet injection (P < 0.0517) .In the control group, union was observed in 14 (77.8 %) patients (P = 0.672). The average time to union following percutaneous bone marrow injection was 11.6 weeks (range 9 to 28 weeks). The proximal 1/3 shaft non union healed comparatively faster than the distal 1/3 shaft tibia (P ≤ 0.0612). No correlation was observed between the comminuted and non comminuted fracture non union (P = 0.789). A significant correlation was noted as regards the non union healing time duration in patients who were on insulin and oral hypoglycemic drugs (P ≤ 0.001) and also about the total duration of diabetes mellitus in years (P ≤ 0.003). CONCLUSION: This investigation showed that percutaneous autologous platelet gel delivery is sufficient method to obtain union in diabetic tibial fracture non unions, which is less invasive procedure than bone marrow injection. The efficacy of this autologous platelets is once again well established and this study reinforced categorically the previously published report by the author.

Operative Management of Pediatric Physeal Bar Development and Genu Valgum.

Background: Pediatric orthopedic conditions present unique challenges due to ongoing skeletal growth and development. Managing these cases requires addressing both structural anomalies and functional deficits. Care presentation: This case report discusses a 13-year-old male with recurrent left knee pain exacerbated by physical activity. The patient's history of a left knee infection at 1.5 years of age, possibly septic arthritis or osteomyelitis, underscores the long-term consequences of early pathology on skeletal growth and alignment. Imaging studies revealed a distal lateral femur physis bar and genu valgum, necessitating surgical intervention. Management and Outcomes: The surgery involved medial distal femur hemiepiphysiodesis and lateral distal femur bar excision to correct anatomical deformities and restore optimal limb alignment and function. Postoperative rehabilitation, including targeted exercises to improve quadriceps strength, was crucial for functional recovery and reducing the risk of complications such as medial patellofemoral pain. Conclusion: This case highlights the importance of a multidisciplinary approach in managing complex pediatric orthopedic cases.

An Outcome Analysis of Pediatric Diaphyseal Fractures Treated Surgically With the Titanium Elastic Nailing System.

Introduction Pediatric fractures account for one-fourth of all pediatric injuries. Stabilizing the fracture, regulating the length and alignment, encouraging bone healing, and minimizing morbidity and problems for the child and family are the objectives of treatment for diaphyseal fractures of long bones in children. Our goal is to investigate how pediatric diaphyseal long bone fractures are treated with a titanium elastic nailing system (TENS). Methods A prospective interventional study was conducted on 24 children who had displaced diaphyseal fractures of major long bones, involving 31 diaphyseal fractures of long bones. Utilizing Flynn's grading standards, the result was examined. Results The mean age was 12.20 years. The youngest child was seven years old and the eldest child was 16 years old. There were 20 boys (83.33%) and four girls (16.67%). The male-to-female ratio was noted to be 5:1. The commonest mode of injury was road traffic accidents (12 cases, 50%), followed by falls while playing (10 cases, 41.67%). Other causes included falls from height (one case, 4.17%) and blunt trauma (one case, 4.17%). The commonest bone to get fractured was the femur (37.50%), followed by both bones of the forearm (29.17%), tibia (20.83%), humerus (8.33%), and ulna alone (4.17%). The middle third (21 fractures, 67.74%) was the most prevalent location for fractures. Five fractures each (16.13%) accounted for in the proximal and distal thirds. Twelve fractures (38.71%) were detected on the left side, while the majority of fractures (19 fractures, 61.29%) were seen on the right side. Most of the fractures in this group were transverse fractures (18 fractures, 58.06%) followed by oblique fractures (eight fractures, 25.81%). Comminuted fractures accounted for five fractures (16.13%). Of the 31 fractures, open reduction had to be done in two fractures, after unsuccessful attempts at closed reduction. Closed reduction was done in 29 fractures. There were 15.12 weeks in the average union term. The range is six weeks to 39 weeks. The most frequent side effect was discovered to be skin irritation at the entry site. The extraosseous portion of nails caused irritation at two entry sites (6.45%). A case had delayed union (3.23%) and restricted knee range of movements. Conclusion For the treatment of juvenile diaphyseal fractures of the long bones, the TENS is the best option. It is a quick, straightforward, safe, dependable, and efficient way to treat pediatric long-bone fractures in patients aged five to 16 years. The healing process takes a fair amount of time, while the surgery takes less time. It does away with the necessity for extended bed rest and significantly shortens hospital stays. It provides stability and elastic mobility, which is perfect for early mobilization and quick union at the fracture site. It has a low rate of complications and produces excellent functional results.

The "toxic window" of amoxicillin exposure during pregnancy on long bone development in fetal mice.

AIMS: Amoxicillin is a broad-spectrum beta-lactam antibiotic used to treat infectious diseases in pregnant women. Studies have shown that prenatal amoxicillin exposure (PAmE) has developmental toxicity on fetal development. However, the effect of PAmE on long bone development has not been reported. This study aimed to investigate the "toxic window" of PAmE on long bone development and explore its possible mechanism in fetal mice. MATERIALS AND METHODS: Pregnant mice were administered amoxicillin by gavage at different stages (gestational day (GD)10-12 and GD16-18), different doses (150 and 300 mg/kg·d) and different courses (single and multiple courses). Fetal femurs were collected at GD18 and bone development related indicators were detected. KEY FINDINGS: The results showed that PAmE significantly reduced the length of the femur and primary ossification center of fetal mice, and inhibited the development of fetal growth plate. Meanwhile, PAmE inhibited the development of bone marrow mesenchymal stem cells, osteoclasts and endothelial cells in fetal long bone. Further, we found the fetal long bone developmental toxicity induced by PAmE was most significant at late-pregnancy (GD16-18), high dose (300 mg/kg·d) and multiple-course group. Besides, PAmE inhibited the expression of Wnt/ß-catenin signaling pathway in fetal long bone. The ß-catenin mRNA expression was significantly positively correlated with the development indexes of fetal long bone. SIGNIFICANCE: PAmE has toxic effects on long bone development, and there was an obvious "toxic window" of PAmE on the long bone development in fetal mice. The Wnt/ß-catenin signaling pathway may mediate PAmE-induced fetal long bone development inhibition.

Comparing the Outcomes of Titanium and Stainless Steel Flexible Nails in Repairing Pediatric Long Bone Fractures.

Background: Traditionally, pediatric femoral fracture treatment favored conservative methods, relying on casting and the inherent bone remodeling ability in immature bones. Surgical intervention was deferred until age 6, as nonoperative approaches often resulted in complications. Titanium elastic nailing (TENS) emerged as an effective treatment for diaphyseal femoral fractures in ages 6 to 16. However, the choice between TENS and stainless steel elastic nailing (SSENS) remains debated due to inconsistent findings. Objective: This study aimed to evaluate the effectiveness of both nailing systems in pediatric long bone fractures. Methods: A retrospective chart review at William Beaumont Hospital Royal Oak included 83 patients aged 6 to 16 treated with TENS or SSENS between January 2011 and January 2021. Data collected encompassed nail related issues, time to fracture union, full weight bearing, and nail removal. Results: In the TENS group (n=29), the average age was 8.8±2.4 years, and the average BMI was 17.2±3.4. The SSENS group (n=54) had an average age of 9.3±2.7 and an average BMI of 19.7±8.4. Time to fracture union for TENS was 93.8±60.5 days, while SSENS was 82.2±40.0 days. Conclusion: This study found no statistically significant differences in nail-related complications, time to fracture union, full weight bearing, or nail removal between TENS and SSENS in pediatric long bone fractures. The choice between these systems should be based on individual circumstances. Limitations include a small sample size and the study's retrospective nature.

Efficacy and safety of autologous or allogeneic mesenchymal stromal cells from adult adipose tissue expanded and combined with tricalcium phosphate biomaterial for the surgical treatment of atrophic nonunion of long bones: a phase II clinical trial.

BACKGROUND: Autologous bone grafting is the standard treatment for the surgical management of atrophic nonunion of long bones. Other solutions, such as bone marrow mesenchymal stem cells (BM-MSC) combined with phospho-calcium material, have also been used. Here we evaluate the safety and early efficacy of a novel procedure using autologous or allogenic adipose tissue mesenchymal stromal cells (AT-MSC) seeded in a patented tricalcium phosphate-based biomaterial for the treatment of bone regeneration in cases of atrophic nonunion. METHODS: This was a prospective, multicentric, open-label, phase 2 clinical trial of patients with atrophic nonunion of long bones. Biografts of autologous or allogenic AT-MSC combined with a phosphate substrate were manufactured prior to the surgical procedures. The primary efficacy was measured 6 months after surgery, but patients were followed for 12 months after surgery and a further year out of the scope of the study. All adverse events were recorded. This cohort was compared with a historical cohort of 14 cases treated by the same research team with autologous BM-MSC. RESULTS: A total of 12 patients with atrophic nonunion of long bones were included. The mean (SD) age was 41.2 (12.1) years and 66.7% were men. Bone healing was achieved in 10 of the 12 cases (83%) treated with the AT-MSC biografts, a percentage of healing similar (11 of the 14 cases, 79%) to that achieved in patients treated with autologous BM-MSC. Overall, two adverse events, in the same patient, were considered related to the procedure. CONCLUSIONS: The results of this study suggest that AT-MSC biografts are safe for the treatment of bone regeneration in cases of atrophic nonunion and reach high healing rates. TRIAL REGISTRATION: Study registered with EUDRA-CT (2013-000930-37) and ClinicalTrials.gov (NCT02483364).

Evaluation of adipose-derived stem cells (ASCS) exosome implantation and platelet-rich fibrin (PRF) on critical long bone defects in Sprague-Dawley rats.

INTRODUCTION: This study aimed to assess the efficacy of adipose-derived mesenchymal stem cell exosomes (ASCs exosome) and platelet-rich fibrin (PRF) in treating critical long bone defects in Sprague-Dawley rats. Critical long bone defects, defined as exceeding 2 cm or 50% of the bone diameter, often pose a healing challenge. While autologous bone grafts have been considered, they have shown unreliable results and donor-site complications, necessitating alternative treatments. METHODS: The research followed a quasi-experimental post-test only control group design involving 30 male Sprague-Dawley rats. The rats were divided into five groups and subjected to femur bone defect creation, internally fixed with a 1.4 mm K-wire, and treated with various combinations of hydroxyapatite (HA), bone graft (BG), ASCs exosome, and PRF. Histomorphometry and BMP-2 gene expression analysis were performed to evaluate bone healing. RESULTS AND DISCUSSION: The results indicated that the group treated with HA + BG + ASCs exosome (group IV) exhibited the highest BMP-2 gene expression, while group III (HA + BG + ASCs exosome + PRF) had the highest chordin level. Overall, groups receiving ASCs exosome or PRF intervention showed elevated BMP-2 expression compared to the control group. The use of ASCs exosome and PRF showed comparable outcomes compared to bone graft administration in terms of histomorphometry analysis. CONCLUSION: The administration of adipose tissue derived mesenchymal stem cells and PRF has a comparable outcome with the use of bone graft in terms of osseus area and expression of BMP-2 in critical bone defect.

Cerebral fat embolism with turbid urine as the initial sign.

BACKGROUND: Cerebral fat embolism (CFE) is a rare but potentially fatal complication that can occur after long bone fractures. It represents one subcategory of fat embolisms (FE). Diagnosing CFE can be challenging due to its variable and nonspecific clinical manifestations. We report a case of CFE initially presenting with turbid urine, highlighting an often neglected sign. CASE PRESENTATION: A 69-year-old male was admitted after a traffic accident resulting in bilateral femoral fractures. Sixteen hours post-admission, grossly turbid urine was noted but received no special attention. Four hours later, he developed rapid deterioration of consciousness and respiratory distress. Neurological examination revealed increased upper limb muscle tone and absent voluntary movements of lower limbs. Brain MRI demonstrated a 'starfield pattern' of diffuse punctate lesions, pathognomonic for CFE. Urine microscopy confirmed abundant fat droplets. Supportive treatment and fracture fixation were performed. The patient regained consciousness after 3 months but had residual dysphasia and limb dyskinesia. CONCLUSION: CFE can present with isolated lipiduria preceding overt neurological or respiratory manifestations. Heightened awareness of this subtle sign in high-risk patients is crucial for early diagnosis and intervention. Prompt urine screening and neuroimaging should be considered when gross lipiduria occurs after long bone fractures.

Long bone uninfected non-union: grafting techniques.

Long bone non-unions represent a serious clinical and socioeconomical problem due to the prolonged episodes, frequent sequelae, and variable treatment effectiveness. Bone grafts, classically involving the autologous iliac crest graft as the 'gold standard' bone graft, enhance bone regeneration and fracture healing incorporating osteoconductive and/or osteoinductive/osteogenic capacity to the non-union under treatment. Structural alternatives to autologous bone grafts include allografts and bone substitutes, expanding the available stock but loosing biological properties associated with cells in the graft. Biological alternatives to autologous bone grafts include bone marrow concentration from iliac crest aspiration, bone marrow aspiration from reaming of the diaphyseal medullary canal in the long bones, and isolated, expanded mesenchymal stem cells under investigation. When the combination with natural and synthetic bone substitutes allows for larger volumes of structural grafts, the enhancement of the biological regenerative properties through the incorporation of cells and their secretoma permits to foresee new bone grafting solutions and techniques.

Effectiveness and safety of augmentative plating technique in managing nonunion following intramedullary nailing of long bones in the lower extremity: A systematic review and meta-analysis.

PURPOSE: To methodically assess the effectiveness of augmentative plating (AP) and exchange nailing (EN) in managing nonunion following intramedullary nailing for long bone fractures of the lower extremity. METHODS: PubMed, EMBASE, Web of Science, and the Cochrane Library were searched to gather clinical studies regarding the use of AP and EN techniques in the treatment of nonunion following intramedullary nailing of lower extremity long bones. The search was conducted up until May 2023. The original studies underwent an independent assessment of their quality, a process conducted utilizing the Newcastle-Ottawa scale. Data were retrieved from these studies, and meta-analysis was executed utilizing Review Manager 5.3. RESULTS: This meta-analysis included 8 studies involving 661 participants, with 305 in the AP group and 356 in the EN group. The results of the meta-analysis demonstrated that the AP group exhibited a higher rate of union (odds ratio: 8.61, 95% confidence intervals (CI): 4.12 - 17.99, p < 0.001), shorter union time (standardized mean difference (SMD): -1.08, 95 % CI: -1.79 - -0.37, p = 0.003), reduced duration of the surgical procedure (SMD: -0.56, 95 % CI: -0.93 - -0.19, p = 0.003), less bleeding (SMD: -1.5, 95 % CI: -2.81 - -0.18), p = 0.03), and a lower incidence of complications (relative risk: -0.17, 95 % CI: -0.27 - -0.06, p = 0.001). In the subgroup analysis, the time for union in the AP group in nonisthmal and isthmal nonunion of lower extremity long bones was shorter compared to the EN group (nonisthmal SMD: -1.94, 95 % CI: -3.28 - -0.61, p < 0.001; isthmal SMD: -1.08, 95 % CI: -1.64 - -0.52, p = 0.002). CONCLUSION: In the treatment of nonunion in diaphyseal fractures of the long bones in the lower extremity, the AP approach is superior to EN, both intraoperatively (with reduced duration of the surgical procedure and diminished blood loss) and postoperatively (with an elevated union rate, shorter union time, and lower incidence of complications). Specifically, in the management of nonunion of lower extremity long bones with non-isthmal and isthmal intramedullary nails, AP demonstrated shorter union time in comparison to EN.

Low-dose short infusion ketamine as adjunct to morphine for acute long bone fracture in the emergency department: a randomized controlled trial.

BACKGROUND: Ketamine is recognized as an alternative for pain management; however, concerns about emergent adverse reactions have limited its widespread adoption. This study aimed to assess the efficacy of a short infusion of low-dose ketamine (LDK) compared to intravenous morphine (MOR) as adjunctive analgesia for acute long bone fracture pain. METHODS: This single-blinded, randomized controlled trial was conducted in a single emergency department. Patients with acute long bone fractures and numerical rating scale (NRS) pain scores ≥ 6 following an initial dose of intravenous morphine were assigned to receive either a LDK (0.3 mg/kg) over 15 min or intravenous MOR at a dose of 0.1 mg/kg administered over 5 min. Throughout a 120-min observation period, patients were regularly evaluated for pain level (0-10), side effects, and the need for additional rescue analgesia. RESULTS: A total of 58 subjects participated, with 27 in the MOR group and 31 in the LDK group. Demographic variables and baseline NRS scores were comparable between the MOR (8.3 ± 1.3) and LDK (8.9 ± 1.2) groups. At 30 min, the LDK group showed a significantly greater mean reduction in NRS scores (3.1 ± 2.03) compared to the MOR group (1.8 ± 1.59) (p = 0.009). Similarly, at 60 min, there were significant differences in mean NRS score reductions (LDK 3.5 ± 2.17; MOR mean reduction = 2.4, ± 1.84) with a p-value of 0.04. No significant differences were observed at other time intervals. The incidence of dizziness was higher in the LDK group at 19.4% (p = 0.026). CONCLUSION: Short infusion low-dose ketamine, as an adjunct to morphine, is effective in reducing pain during the initial 30 to 60 min and demonstrated comparability to intravenous morphine alone in reducing pain over the subsequent 60 min for acute long bone fractures. However, it was associated with a higher incidence of dizziness. TRIAL REGISTRATION: NMRR17318438970 (2 May 2018; www.nmrr.gov.my ).

Comparison of analgesic efficacy of ibuprofen and dexketoprofen in pain management of long bone fractures: a prospective, randomized, double-blind study.

INTRODUCTION: Long bone fractures (LBF) often cause severe pain, impacting patients' quality of life. This prospective, randomized, double-blind study aimed to compare the analgesic efficacy of dexketoprofen (Dex) and ibuprofen (Ibu) in LBF patients in the emergency department. METHODS: Conducted between August 10, 2023, and January 17, 2024, the study included 100 eligible patients randomized into Dex and Ibu groups. Visual analog scale (VAS) scores were measured at baseline and at 30, 60, and 120 min. DeltaVAS (ΔVAS) values and ΔVAS percentages (ΔVAS%) were calculated. Primary endpoints were ΔVAS scores (ΔVAS 30-60-120) and ΔVAS% for comparative analysis. RESULTS: Statistical analysis showed no significant difference in ΔVAS30 (p = 0.359). However, ΔVAS60 exhibited a significant difference (p = 0.027), as did ΔVAS120 (p = < 0.001). ΔVAS%30 showed no significance (p = 0.224), but ΔVAS%60 and ΔVAS%120 were clinically and statistically significant (p = 0.017 and p = < 0.001, respectively). CONCLUSION: Ibuprofen 800 mg demonstrated superior analgesic efficacy at 60 and 120 min compared to Dex in long bone fractures. These findings suggest ibuprofen's potential as an effective pain management option in emergency departments.

Pediatric Acute Compartment Syndrome in Long Bone Fractures: Who is at Risk?

INTRODUCTION: There is a paucity of large-scale data on the factors that suggest an impending or underlying extremity pediatric acute compartment syndrome (ACS). In addition, literature regarding the timing of operative fixation and the risk of ACS is mixed. We aimed to describe the factors associated with pediatric ACS. METHODS: Analysis of 2017-2019 Trauma Quality Improvement Program. We included patients aged <18 y diagnosed with upper extremity (UE) and lower extremity (LE) fractures. Burns and insect bites/stings were excluded. Multivariable regression analyses were performed to identify the predictors of ACS. RESULTS: 61,537 had LE fractures, of which 0.5% developed ACS. 76,216 had UE fractures, of which 0.16% developed ACS. Multivariable regression analyses identified increasing age, male gender, motorcycle collision, and pedestrian struck mechanisms of injury, comminuted and open fractures, tibial and concurrent tibial and fibular fractures, forearm fractures, and operative fixation as predictors of ACS (P value <0.05). Among LE fractures, 34% underwent open reduction internal fixation (time to operation = 14 [8-20] hours), and 2.1% underwent ExFix (time to operation = 9 [4-17] hours). Among UE fractures, 54% underwent open reduction internal fixation (time to operation = 11 [6-16] hours), and 1.9% underwent ExFix (time to operation = 9 [4-14] hours). Every hour delay in operative fixation of UE and LE fractures was associated with a 0.4% increase in the adjusted odds of ACS (P value <0.05). CONCLUSIONS: Our results may aid clinicians in recognizing children who are "at risk" for ACS. Future studies are warranted to explore the optimal timing for the operative fixation of long bone fractures to minimize the risk of pediatric ACS.

Retrospective cohort study analyzing outcomes of the SIGN Fin Nail in adult femoral fractures using the retrograde approach.

Purpose: There is high burden of long bone fractures in low- and middle-income countries (LMICs). Given a limited availability of fluoroscopy in LMICs, the Surgical Implant Generation Network (SIGN) developed two types of intramedullary nails: the SIGN standard nail and the SIGN Fin Nail. A limited number of studies have analyzed healing outcomes with the SIGN Fin Nail and the current study is the largest one to date. The purpose of this study is to compare outcomes between the SIGN standard nail and SIGN Fin Nails in adult femoral shaft fractures treated with a retrograde approach. Method: A retrospective cohort study of adults with femoral shaft fractures was performed using the Sign Online Surgical Database (SOSD). The primary outcome was achieving full painless weight bearing and the secondary outcomes assessed were radiographic healing and infection. A propensity-score adjustment was performed for potential confounders and effect modification due to fracture location was tested using a Mantel-Haenszel test for heterogeneity. Results: Of 19,928 adults with femoral shaft fractures, 2,912 (14.7%) had the required 6-month follow-up to be included. The overall propensity score weighted relative risk between the Fin and Standard Nail for achieving painless weight-bearing was 0.99, 95% CI [0.96-1.03] and for radiographical healing was 0.99, 95%CI [0.97-1.02]. The propensity score weighted relative risk for infection was 1.30, 95% [0.85-1.97]. Use of the Fin nail was also significantly associated with shorter surgery times (p < 0.005, effect size = 24 min). Sub-group analysis based on fracture location and injury cause demonstrated no change in relative risk. Conclusion: The Fin nail showed no change in relative risk in terms of achieving full painless weightbearing or radiographic healing compared to the standard nail for retrograde nailing of femoral shaft fractures in adults. The heterogeneous nature of the cohort and large sample size allow for generalizability and add to a growing base of literature supporting use of the Fin Nail for retrograde femoral nailing. However, there are limitations as we could not correct for comminution at the fracture site or measure radiographic alignment or shortening.

Finite element method analysis of bone stress for variants of locking plate placement.

This study investigates the optimal placement of locking plate screws for bone fracture stabilization in the humerus, a crucial factor for enhancing healing outcomes and patient comfort. Utilizing Finite Element Method (FEM) modeling, the research aimed to determine the most effective screw configuration for achieving optimal stress distribution in the humerus bone. A computer tomography (CT) scan of the humerus was performed, and the resulting images were used to create a detailed model in SOLIDWORKS 2012. This model was then analyzed using ANSYS Workbench V13 to develop a finite element model of the bone. Four different screw configurations were examined: 4 × 0°, 4 × 10°, 4 × 20°, 2 × 20°; 2 × 0°. These configurations were subjected to bending in the XZ and YZ planes, as well as tension and compression along the Z axis. The research identified the 2 × 20°+2 × 0° configuration as the most beneficial, with average stress values below 30 MPa and peak stress values below 50 MPa in 3-point bending at the first screw. This configuration consistently showed the lowest stress values across all loading scenarios. Specifically, stress levels ranged from 20 MPa to 50 MPa for bending in the XZ plane, 20 MPa-35 MPa for bending in the YZ plane, 20 MPa-30 MPa for extension in the Z-axis, and 18 MPa-25 MPa for compression in the Z-axis. The 4 × 10° and 4 × 20° configurations also produced satisfactory results, with stress levels not exceeding 70 MPa. However, the 4 × 0° configuration presented considerable stress during bending and compression in the Z-axis, with stress values exceeding 100 MPa, potentially leading to mechanical damage. In conclusion, the 2 × 20°; 2 × 0° screw configuration was identified as the most effective in minimizing stress on the treated bone. Future work will involve a more detailed analysis of this methodology and its potential integration into clinical practice, with a focus on enhancing patient outcomes in bone fracture treatment.

Age-related changes in densitometry and histomorphometry of long bone during the pubertal growth spurt in male rats.

Because experimental studies to determine the developmental toxicity of exposure to various substances in children are impossible, many studies use immature male rats. This study aimed to provide normative data for longitudinal bone growth with age during the puberty in male rats. In order to evaluate long bone growth and mineralization we examined bone size and bone density by dual-energy X-ray absorptiometry, analyzed histomorphometry of the growth plate, and serum hormone levels relevant to bone growth from postnatal day (PD)20 to PD60. The length and weight of long bones increased strongly by PD40, and no further increase was observed after PD50. On the other hand, tibial growth plate height decreased sharply after PD50 along with a reduction in the number of cells and columns, which was probably responsible for the absence of further lengthening of long bones. Parameters related to bone formation such as bone area ratio, and the thickness and number of trabeculae, also increased significantly between PD40 and PD50. Furthermore, serum levels of IGF-1 peaked at PD30 and testosterone increased rapidly on and after PD40, when IGF-1 levels were going down. These changes may participate in the parallel increase in mineral acquisition, as well as lengthening of long bones. Our findings provide comprehensive data for changes in bone density, histomorphometry of long bones, and hormone levels relevant to bone growth during the growth spurt. This will be useful for planning animal toxicological studies, particularly for deciding on the appropriate age of animals to use in given experiments.