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Purpose: Surgical intervention for lateral compression (LC) 1 and 2 pelvic ring fractures is controversial. Posterior ring stabilization remains the most common mode of initial fixation. However, greater mechanical instability is observed in the anterior component of LC pelvic fractures. This study tested whether reduction and percutaneous superior ramus fixation will decrease the instability of LC pelvic fractures on intraoperative fluoroscopic imaging. Methods: All adult patients (≥ 18 years) presenting with either a Young–Burgess LC1 or LC2 pelvic ring disruption treated operatively with percutaneous anterior followed by posterior fixation by a single surgeon from July 2021 to June 2023 were retrospectively reviewed. Displacement of the anterior ring to intraoperative manual internal rotation stress examination under fluoroscopy was compared before and after anterior pelvic ring reduction and fixation and prior to posterior pelvic ring fixation. Pre- and post-operative visual analog scores (VAS) for pain were also compared. Results: Twenty-one patients with a mean age of 48.7 years were included. Fifteen patients (71.4%) presented with an LC1, and six (28.6%) with an LC2 injury patterns. Anterior pelvic fixation alone provided 7.5mm reduction in mean displacement of the anterior pelvic ring (pre-operative = 9.2 mm vs. post-operative = 1.6 mm, p < 0.001). VAS significantly decreased from 7.2 one-day pre-operatively to 2.2 twenty-four h post-operatively (p < 0.001). Conclusions: Reduction and fixation of the anterior pelvic ring prior to posterior fixation for LC1 and LC2 pelvic ring disruptions substantially improves mechanical stability on intraoperative stress examination. Combination of percutaneous anterior and posterior fixation significantly decreased VAS above the MCID 24 h after stabilization. [ABSTRACT FROM AUTHOR]

Purpose: To determine if subchondral rafting wires retained as adjunctive tibial plateau fracture fixation affect postoperative articular subsidence. Methods: A retrospective cohort study was conducted at one Level 1 trauma center and one academic university hospital. Consecutive adults with closed, displaced OTA/AO 41B/C tibial plateau fractures treated between 2018 and 2023 with open reduction internal fixation were included. Patients who were not ambulatory, with contralateral injuries limiting weight bearing, and without follow-up radiographs of the injured extremity were excluded. The intervention was retention of subchondral rafting wires as definitive fixation. The primary outcome was linear articular surface subsidence between postoperative and follow-up AP knee radiographs. Linear subsidence was compared between groups using Welch's two sample t test. Associations of linear subsidence with patient, injury, and treatment characteristics were assessed by multivariable linear regression. Results: We identified 179 patients of a mean age of 44 ± 14 years, of whom 15 (8.4%) received subchondral rafting wires. Median follow-up was 121 days. No patients who received rafting wires as definitive implants experienced linear subsidence ≥ 2 mm, while 22 patients (13.4%) who did not receive rafting wires experienced linear subsidence ≥ 2 mm (p = 0.130). Subchondral rafting wires were associated with less linear subsidence (0.3 mm [95% confidence interval − 0.3–0.9 mm] vsersus 1.0 mm [− 0.9–2.9 mm], p < 0.001). The depth of linear subsidence was significantly associated on multivariable regression with male sex, depressed plateau area, active smoking, and retained rafting wires. Conclusion: Subchondral rafting wires were associated with a small reduction in articular subsidence after internal fixation of tibial plateau fractures. Routine rafting wires may be useful for patients and fractures at high risk of articular subsidence. [ABSTRACT FROM AUTHOR]

Purpose: Determine if anterior internal versus supra-acetabular external fixation of unstable pelvic fractures is associated with care needs or discharge. Methods: A retrospective cohort study was performed at two tertiary trauma referral centers. Adults with unstable pelvis fractures (AO/OTA 61B/61C) who received operative fixation of the anterior and posterior pelvic ring by two orthopedic trauma surgeons from October 2020 to November 2022 were included. The primary outcome was discharge destination. Secondary outcomes included intensive care unit (ICU) or ventilator days, length of stay, and hospital charges. Results: Eighty-three eligible patients were 38.6% female, with a mean age of 47.2 ± 20.3 years and BMI 28.1 ± 6.4 kg/m2. Fifty-nine patients (71.1%) received anterior pelvis internal fixation and 24 (28.9%) received external fixation. External fixation was associated with weight-bearing restrictions (91.7% versus 49.2%, p = 0.01). No differences in demographic, functional status, insurance type, fracture classification, or injury severity measures were observed by treatment. Internal versus external anterior pelvic fixation was not associated with discharge to home (49.2% versus 29.2%, p = 0.10), median ICU days (3.0 [interquartile range (IQR) 7.8 versus 5.5 [IQR 4.3], p = 0.14, ventilator days (0 [IQR 6.0] versus 0 [IQR 2.8], p = 0.51), length of stay (13.0 [IQR 13.0] versus 17.5 (IQR 20.5), p = 0.38), or total hospital charges (US dollars 180,311 [IQR 219,061.75] versus 243,622 [IQR 187,111], p = 0.14). Conclusions: Anterior internal versus supra-acetabular external fixation of unstable pelvis fractures was not significantly associated with discharge destination, critical care, hospital length of stay, or hospital charges. This sample may be underpowered to detect differences between groups. Level of Evidence: Therapeutic Level IV. [ABSTRACT FROM AUTHOR]

Introduction: Distal femur fractures account for 3–6% of all femur fractures. Internal fixation of most distal femur fractures with an anatomic lateral locking plate should permit some motion at the metaphyseal portion of the fracture when secondary bone healing is planned by the operating surgeon. While several studies have been performed evaluating union rates for distal femur fractures with stainless steel and titanium plates, the timing of callus formation between stainless steel and titanium implants used as bridge plates for distal femur fractures (AO/OTA 33-A and -C) has been investigated to a lesser extent. We hypothesize that callus will be visualized earlier with post-operative radiographs with titanium versus stainless steel bridge plates. Methods: We retrospectively reviewed a consecutive cohort of patients over 18 years of age with acute AO/OTA 33-A and 33-C fracture patterns treated with an isolated stainless steel or titanium lateral bridge plate within 4 weeks of injury by a single fellowship-trained orthopedic trauma surgeon from 2011 to 2020 at one academic Level 1 trauma center. An independent, fellowship-trained orthopedic trauma attending surgeon reviewed anterior–posterior (AP) and lateral radiographs from every available post-operative clinic visit and graded them using the Modified Radiographic Score for Tibia (mRUST). Results: Twenty-five subjects were included in the study with 10 with stainless steel and 15 with titanium plates. There were no significant differences in demographics between both groups, including age, sex, BMI, injury classification, open versus closed, mechanism, and laterality. Statistically significant increased mRUST scores, indicating increased callus formation, were seen on 12-week radiographs (8.4 vs. 11.9, p = 0.02) when titanium bridge plates were used. There were no statistically significant differences in mRUST scores at 6 or 24-weeks, but scores in the titanium group were higher in at every timepoint. Discussion: In conclusion, we observed greater callus formation at 12 weeks after internal fixation of 33-A and 33-C distal femur fractures treated with titanium locked lateral distal femoral bridge plates compared to stainless steel plates. Our data suggest that titanium metallurgy may have quicker callus formation compared to stainless steel if an isolated, lateral locked bridge plate is chosen for distal femur fracture fixation. [ABSTRACT FROM AUTHOR]

Purpose: Open reduction internal fixation of tibial plateau and pilon fractures may be complicated by deep surgical site infection requiring operative debridement and antibiotic therapy. The management of superficial surgical site infection is controversial. We sought to determine whether superficial infection is associated with an increased risk of deep infection requiring surgical debridement after fixation of tibial plateau and pilon fractures. Methods: This is a secondary analysis of data from the VANCO trial, which included 980 adult patients with a tibial plateau or pilon fracture at elevated risk of infection who underwent open reduction internal fixation with plates and screws with or without intrawound vancomycin powder. An association of superficial surgical site infection with deep surgical site infection requiring debridement surgery and antibiotics was explored after matching on risk factors for deep surgical site infection. Results: Of the 980 patients, we observed 30 superficial infections (3.1%) and 76 deep infections (7.8%). Among patients who developed a superficial infection, the unadjusted incidence of developing a deep infection within 90 days was 12.8% (95% confidence interval [CI] 1.3–24.2%). However, after a 3:1 match on infection risk factors, the 90-day marginal probability of a deep surgical site infection after sustaining a superficial infection was 6.0% (95% CI − 6.5–18.5%, p = 0.35). Conclusion: Deep infection after superficial infection is uncommon following operative fixation of tibial plateau and pilon fractures. Increased risk of subsequent deep infection attributable to superficial infection was inconclusive in these data. Level of evidence: Prognostic Level II. [ABSTRACT FROM AUTHOR]

Purpose: To estimate survival of acetabular fracture repair by tracking patients across healthcare encounters. We hypothesized that hip survival estimated this way would be lower than reported by single-surgeon or single-center series not capturing censored reoperations. Methods: Retrospective health insurance administrative database cohort study. All claimed healthcare encounters for employer-sponsored health insurance beneficiaries aged 18−65 years without pre-existing hip pathology with a newly diagnosed acetabular fracture were identified between October 1, 2015, through December 31, 2018. The intervention was open reduction internal fixation of acetabular fracture during index admission. The primary outcome was survival of the acetabular fracture repair to subsequent reoperation by arthroscopy, arthrotomy for drainage of infection, implant removal, revision acetabular fixation, hip arthroplasty, hip resection, or arthrodesis. Results: 38 reoperation procedures on the fractured acetabulum in 852 patients occurred within 2 years (incidence 4.5%). Total hip arthroplasty (2.5%) and revision internal fixation (1.5%) accounted for most early reoperations. Multivariable Cox regression identified an association between reoperation and increasing patient age (hazard ratio = 1.4 per decade, p < 0.01). The prevalence of any mental health condition was 29%. Conclusions: Non-elderly adults with employer-sponsored insurance who sustain acetabular fractures have a greater burden of mental health disease than similarly insured patients without these injuries. Survival of the native acetabulum after fracture fixation exceeded 95% at 2 years and decreased with increasing patient age. Level of evidence: Level III, Prognostic Study. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the sensitivity of a screening test for pelvic ring disruption, the AP pelvis radiograph, for clinically serious U-type sacral fractures which merit consultation with an orthopedic trauma specialist and may require transfer to a higher level of care. Methods: Retrospective clinical cohort of 63 consecutive patients presenting with U-type sacral fractures at one level 1 trauma referral center from January 2006 through December 2019. The sensitivity of the first AP pelvis radiograph obtained on admission, interpreted without reference to antecedent or concomitant pelvis computed tomography (CT) by a radiologist and a panel of three blinded orthopedic traumatologists, was determined against a reference diagnosis made from review of all pelvis radiographs, CT images, operative reports, and clinical documentation. Results: Sensitivity of AP pelvis radiograph for U-type sacral fractures was 2% as interpreted by a radiologist and mean 12% (range 5–27%) as interpreted by orthopedic traumatologists with poor inter-rater agreement (Fleiss' κ = 0.11). 94% of sacra were at obscured by radiographic artifact. Conclusion: The sensitivity of an AP pelvis radiograph is poor for U-type sacral fractures, whether interpreted by radiologists or orthopedic traumatologists. Pelvis CT should be considered as a screening test to rule out sacral fracture when the patient reports posterior pelvic pain, even if plain radiography demonstrates no injury or a minimally displaced pelvic ring disruption. Level of evidence: Diagnostic level III [ABSTRACT FROM AUTHOR]

An isolated avulsion fracture involving the femoral origin of the medial head of the gastrocnemius muscle without an associated muscular, meniscal, or ligamentous injury is extremely rare. We report a case of a 14-year-old male wrestler who presented with a radiographically occult avulsion fracture of the medial gastrocnemius tendon sustained during competition. To our knowledge, this is the first case to describe a mechanism of injury as well as to report a return to competition after non-operative management. [ABSTRACT FROM AUTHOR]

Segregation and templating approaches have been honed by billions of years of evolution to direct many complex biological processes. Nature uses segregation to improve biochemical control by organizing reactants into defined, well-regulated environments, and the transfer of genetic information is a primary function of templating. The ribosome, wherein messenger RNA is translated into polypeptides, combines both techniques to allow for ideal biopolymer syntheses. Herein is presented a biomimetic segregation/templating approach to synthetic radical polymerization. Polymerization of a nucleobase-containing vinyl monomer in the presence of a complementary block copolymer template of low molecular weight yields high molecular weight (Mw up to ~400,000 g mol?1), extremely low polydispersity (?1.08) daughter polymers. Control is attained by segregation of propagating radicals in discrete micelle cores (via cooperative assembly of dynamic template polymers). Significantly reduced bimolecular termination, combined with controlled propagation along a defined number of templates, ensures unprecedented control to afford well-defined high molecular weight polymers. [ABSTRACT FROM AUTHOR]

The self-assembly of block copolymers into 1D, 2D and 3D nano- and microstructures is of great interest for a wide range of applications. A key challenge in this field is obtaining independent control over molecular structure and hierarchical structure in all dimensions using scalable one-pot chemistry. Here we report on the ring opening polymerization-induced crystallization-driven self-assembly (ROPI-CDSA) of poly-L-lactide-block-polyethylene glycol block copolymers into 1D, 2D and 3D nanostructures. A key feature of ROPI-CDSA is that the polymerization time is much shorter than the self-assembly relaxation time, resulting in a non-equilibrium self-assembly process. The self-assembly mechanism is analyzed by cryo-transmission electron microscopy, wide-angle x-ray scattering, Fourier transform infrared spectroscopy, and turbidity studies. The analysis revealed that the self-assembly mechanism is dependent on both the polymer molecular structure and concentration. Knowledge of the self-assembly mechanism enabled the kinetic trapping of multiple hierarchical structures from a single block copolymer. A key challenge in the self-assembly of block copolymers is obtaining independent control over molecular structure and hierarchical structure in all dimensions using scalable one-pot chemistry. Here the authors show the ring opening polymerization-induced crystallization-driven self-assembly of poly-L-lactide-block-polyethylene glycol block copolymers into 1D, 2D and 3D nanostructures. [ABSTRACT FROM AUTHOR]