Insertion sites of iliosacral screws on the posterior ilium: Implications for posterior pelvic fixation.

OBJECTIVES: Lateral compression type II pelvic ring injuries can be treated with fixation through open or percutaneous approaches depending on the injury pattern and available osseous fixation pathways. The start site of iliosacral screws to stabilize these injuries should be on the unstable posterior iliac fragment; however, our understanding of start sites for iliosacral screws has not been developed. The purpose of this study is to provide an analysis of iliosacral screw start sites on the posterior ilium to help guide treatment of pelvic ring injuries. METHODS: One-hundred and seventeen consecutive patients at an academic level I trauma center with pelvic ring injuries who underwent surgical treatment with iliosacral screws were included in the final analysis. The start sites of iliosacral screws with confirmed intraosseous placement on a postoperative computed tomography were mapped on the posterior ilium and analyzed according to the sacral segment and type of iliosacral screw. RESULTS: One-hundred and seventeen patients were included in the final analysis. Of the total of 272 iliosacral screw insertion sites analyzed, 145 (53%) were sacroiliac-style screws and 127 (47%) were transsacral screws. The insertion sites for sacroiliac-style screws and transsacral screws at different sacral segment levels can vary but have predictable regions on the posterior ilium relative to reliable osseous landmarks. CONCLUSIONS: Iliosacral screws start sites on the posterior ilium have reliable regions that can be used to plan posterior fixation of pelvic ring injuries.

Low reoperation rate after fixation of displaced femoral neck fractures with the femoral neck system (FNS).

PURPOSE: Operative fixation of femoral neck fractures (FNFs) remains challenging. Complications are not infrequent, especially in displaced patterns. Numerous fixation techniques have been previously described in the literature; however, there remains a paucity of data regarding outcomes of these injuries treated with the femoral neck system (FNS). METHODS: Patients with a displaced FNF (OTA/AO 31B) treated with the FNS at a single level 1 academic trauma center between 1/1/2019 and 1/1/2023 were identified. Radiographs were reviewed to assess fracture displacement, location, and characteristics. Patient records were further reviewed to assess for complications, reoperations, and osseous union. RESULTS: Forty-three patients (65% male) with 44 FNFs were identified with a mean age of 35.0 years (range, 13-61 years). Two patients developed a deep infection requiring surgical debridement, four patients underwent a total hip arthroplasty, and one patient underwent a valgus intertrochanteric osteotomy for nonunion. There were three cases of femoral head AVN. Mean follow-up was 482.5 days among all patients, and 36 fractures had at least 6 months of follow-up or reached bony union. CONCLUSIONS: Here, we present a series of patients treated with the FNS for internal fixation and report a 18% reoperation rate. This is lower than the average rate that has been previously reported in similar patient populations in the literature treated with alternative methods of internal fixation. Thus, the FNS appears to be a safe and effective option for treatment of these injuries.

Retrograde intramedullary nailing of AO/OTA 33C femur fractures in patients with below-knee amputations: technical note and case series.

PURPOSE: Intra-articular distal femur fractures in patients with a lower extremity amputation can present a technical challenge for the treating surgeon in what may be otherwise considered a routine procedure in non-amputees. Difficulties with positioning, fracture reduction, limb contractures, and stump osteoporosis can present challenges with treatment. Here, we describe the surgical technique and outcome of a case series of amputee patients with AO/OTA 33C femur fractures. METHODS: Retrospective case series of five patients with a comminuted supracondylar distal femur fracture with intercondylar extension proximal to a below-knee amputation treated with retrograde intramedullary nail at a single Level 1 trauma center from January 1, 2021, to January 1, 2023. Baseline demographic and clinical data were recorded. Rate of bony union and complications were documented. RESULTS: Five patients (three females and two males) with a mean age of 48 years who were treated for a comminuted supracondylar distal femur fracture with intercondylar extension proximal to a below-knee amputation were identified. At the time of final follow-up (mean 109.3 days, range 29-183 days), all patients had healed their incisions and were progressing to return of function with their prosthesis. All patients were treated with the surgical technique described in this article, and no postoperative complications were reported. CONCLUSION: This is an effective and safe technique for surgical treatment of comminuted intra-articular distal femur fractures in patients with an ipsilateral below-knee amputation. We believe that this technique can be utilized by any orthopedic surgeon taking trauma call and can avoid unnecessary transfers or delays to care.

Association of Race With Post-operative Complications After Spinal Fusion in Children With Cerebral Palsy.

INTRODUCTION: Neuromuscular scoliosis in children with cerebral palsy (CP) can lead to debilitating difficulties with pain, ambulation, sitting, and respiratory or cardiac compromise. Spinal fusion can halt deformity progression, though the decision to undergo surgery involves an individualized risk-benefit assessment. The purpose of this study was to evaluate whether race is a risk factor for patients with CP to experience post-operative complications after spinal fusion. METHODS: This is a retrospective cohort analysis of a national database. Analyses methods include univariate analyses, multivariate regression models, and other ad-hoc tests. RESULTS: There were 3,081 pediatric patients with CP who underwent spinal fusion. Black patients had an increased risk of experiencing any post-operative complication compared to Caucasians (OR 1.322, 95% CI 1.099-1.590). Both Caucasian(p=0.005) and Black (p<0.001) races were risk factors for experiencing medical complications; Black patients had an increased risk compared to Caucasians (OR 1.373, 95% CI 1.130-1.667). Other races had a greater length of ICU stay than Caucasians (median {Mdn}=3.00 days vs Mdn=2.00, p=0.029), and longer total hospital stays than Caucasian and Black patients (Mdn=9.00 days vs Mdn=6.00 days vs Mdn=6.00 days, p<0.001). CONCLUSION: Race is an independent risk factor for pediatric patients with CP to experience medical complications following spinal fusion surgery, with Black patients having an increased risk compared to Caucasians. Further, other races were found to have significantly longer ICU and total hospital length of stay. This study is the first to present race as a risk factor for children with CP to experience increased post-operative complications following spinal fusion and will be valuable in understanding their individualized peri-operative courses and risks.

Identification of Toxicity Effects of Cu2O Materials on C. elegans as a Function of Environmental Ionic Composition.

Previous work has shown that spherical CuO nanomaterials show negative effects on cell and animal physiology. The biological effects of Cu2O materials, which posess unique chemical features compared to CuO nanomaterials and can be synthesized in a similarly large variety of shapes and sizes, are comparatively less studied. Here, we synthesized truncated octahedral Cu2O particles and characterized their structure, stability, and physiological effects in the nematode worm animal model, Caenorhabditis elegans. Cu2O particles were found to be generally stable in aqueous media, although the particles did show signs of oxidation and leaching of Cu2+ within hours in worm growth media. The particles were found to be especially sensitive to inorganic phosphate (PO4 3-) found in standard NGM nematode growth medium. Cu2O particles were observed being taken up into the nematode pharynx and detected in the lumen of the gut. Toxicity experiments revealed that treatment with Cu2O particles caused a significant reduction in animal size and lifespan. These toxic effects resembled treatment with Cu2+, but measurements of Cu leaching, worm size, and long-term behavior experiments show the particles are more toxic than expected from Cu ion leaching alone. These results suggest worm ingestion of intact Cu2O particles enhances their toxicity and behavior effects while particle exposure to environmental phosphate precipitates leached Cu2+ into biounavailable phosphate salts. Interestingly, the worms showed an acute avoidance of bacterial food with Cu2O particles, suggesting that animals can detect chemical features of the particles and/or their breakdown products and actively avoid areas with them. These results will help to understand how specific, chemically-defined particles proposed for use in polluted soil and wastewater remediation affect animal toxicity and behaviors in their natural environment.

Interleukin-1ß and tumor necrosis factor are essential in controlling an experimental orthopedic implant-associated infection.

Orthopedic implant-associated infection (OIAI) is a major complication that leads to implant failure. In preclinical models of Staphylococcus aureus OIAI, osteomyelitis and septic arthritis, interleukin-1α (IL-1α), IL-1ß, and tumor necrosis factor (TNF) are induced, but whether they have interactive or distinctive roles in host defense are unclear. Herein, a S. aureus OIAI model was performed in mice deficient in IL-1α, IL-1ß, or TNF. Mice deficient in IL-1ß or TNF (to a lesser extent) but not IL-1α had increased bacterial burden at the site of the OIAI throughout the 28-day experiment. IL-1ß and TNF had a combined and critical role in host defense as mice deficient in both IL-1R and TNF (IL-1R/TNF-deficient mice) had a 40% mortality rate, which was associated with markedly increased bacterial burden at the site of the OIAI infection. Finally, IL-1α- and IL-1ß-deficient mice had impaired neutrophil recruitment whereas IL-1ß-, TNF-, and IL-1R/TNF-deficient mice all had impaired recruitment of both neutrophils and monocytes. Therefore, IL-1ß and TNF contributed to host defense against S. aureus OIAI and neutrophil recruitment was primarily mediated by IL-1ß and monocyte recruitment was mediated by both IL-1ß and TNF.