The Role of the Hip Capsule in Restoring Stability in the Initial Phase of Hip Distraction: An In Vivo Analysis.

Background: The labral suction seal has been shown to provide the majority of resistance in the initial phase of hip distraction. However, the effect of an unrepaired interportal capsulotomy and capsular repair on the initial phase of hip distractive stability in vivo is not well understood. Purpose: To investigate the effect of capsular repair on the initial phase of distractive stability of hip joints in patients with femoroacetabular impingement (FAI) syndrome. Study Design: Controlled laboratory study. Methods: Patients undergoing primary hip arthroscopy for FAI between March and August 2020 were prospectively enrolled. Total joint space was measured on fluoroscopic images at the medial and lateral edges of the sourcil at 12.5-lb (5.7-kg) axial traction intervals (up to 100 lb [45.4 kg]) in 3 capsular states: (1) native capsule, (2) interportal capsulotomy, and (3) capsular repair. Distraction on anteroposterior radiographs was calculated as the difference between total joint space at each traction interval and baseline joint space at 0 lb, normalized to millimeters. The native, capsulotomy, and capsular repair states were compared using Wilcoxon signed-rank and McNemar tests. Results: Included were 36 hips in 35 patients. The median force required to distract ≥3 mm was 75 lb (34.0 kg; 95% CI, 70-80 lb [31.8-36.3 kg]) in both the native and capsular repair states (P = .629), which was significantly greater than the median force required to distract ≥3 mm in the capsulotomy state (50 lb [22.7 kg]; 95% CI, 45-55 lb [20.4-24.9 kg]) (P < .001). The most rapid rates of change in joint space were observed at the traction interval at which hips first achieved ≥3 mm of distraction (n = 33 hips; 92%). Conclusion: The traction force at which hips distracted ≥3 mm was 75 lb (34.0 kg) in both the native capsular and capsular repair states. Significantly less traction force (50 lb [22.7 kg]) distracted hips ≥3 mm in the capsulotomy state. Complete capsular closure after interportal capsulotomy resulted in restoration of initial distractive stability relative to the unrepaired capsulotomy state at time zero after primary hip arthroscopy. Clinical Relevance: This study provides surgeons with an improved understanding of the additional stability to the hip joint from capsular repair after hip arthroscopy for FAI syndrome.

Comparison of Wild-Type and High-risk PNPLA3 variants in a Human Biomimetic Liver Microphysiology System for Metabolic Dysfunction-associated Steatotic Liver Disease Precision Therapy.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a worldwide health epidemic with a global occurrence of approximately 30%. The pathogenesis of MASLD is a complex, multisystem disorder driven by multiple factors including genetics, lifestyle, and the environment. Patient heterogeneity presents challenges for developing MASLD therapeutics, creation of patient cohorts for clinical trials and optimization of therapeutic strategies for specific patient cohorts. Implementing pre-clinical experimental models for drug development creates a significant challenge as simple in vitro systems and animal models do not fully recapitulate critical steps in the pathogenesis and the complexity of MASLD progression. To address this, we implemented a precision medicine strategy that couples the use of our liver acinus microphysiology system (LAMPS) constructed with patient-derived primary cells. We investigated the MASLD-associated genetic variant PNPLA3 rs738409 (I148M variant) in primary hepatocytes, as it is associated with MASLD progression. We constructed LAMPS with genotyped wild type and variant PNPLA3 hepatocytes together with key non-parenchymal cells and quantified the reproducibility of the model. We altered media components to mimic blood chemistries, including insulin, glucose, free fatty acids, and immune activating molecules to reflect normal fasting (NF), early metabolic syndrome (EMS) and late metabolic syndrome (LMS) conditions. Finally, we investigated the response to treatment with resmetirom, an approved drug for metabolic syndrome-associated steatohepatitis (MASH), the progressive form of MASLD. This study using primary cells serves as a benchmark for studies using patient biomimetic twins constructed with patient iPSC-derived liver cells using a panel of reproducible metrics. We observed increased steatosis, immune activation, stellate cell activation and secretion of pro-fibrotic markers in the PNPLA3 GG variant compared to wild type CC LAMPS, consistent with the clinical characterization of this variant. We also observed greater resmetirom efficacy in PNPLA3 wild type CC LAMPS compared to the GG variant in multiple MASLD metrics including steatosis, stellate cell activation and the secretion of pro-fibrotic markers. In conclusion, our study demonstrates the capability of the LAMPS platform for the development of MASLD precision therapeutics, enrichment of patient cohorts for clinical trials, and optimization of therapeutic strategies for patient subgroups with different clinical traits and disease stages.

DO seniors and IMGs have lower match probabilities than MD seniors after adjusting for specialty choice and USMLE Step 1 score.

CONTEXT: It is unknown if US residency applicants of different educational backgrounds (US allopathic [MD], Doctor of Osteopathic Medicine [DO], and international medical graduates [IMG]) but comparable academic performance have similar match success. OBJECTIVES: Our objective was to compare match probabilities between applicant types after adjusting for specialty choice and United States Medical Licensing Examination (USMLE) Step 1 scores. METHODS: We performed a secondary analysis of published data in National Resident Matching Program (NRMP) reports from 2016, 2018, 2020, and 2022 for US MD seniors, DO seniors, and IMGs (US citizens and non-US citizens). We examined the 10 specialties with the most available spots in 2022. Average marginal effects from a multiple variable logistic regression model were utilized to estimate each non-MD senior applicant type's probability of matching into their preferred specialty compared to MD seniors adjusting for specialty choice, Step 1 score, and match year. RESULTS: Each non-MD applicant type had a lower adjusted percent difference in matching to their preferred specialty than MD seniors, -7.1 % (95 % confidence interval [CI], -11.3 to -2.9) for DO seniors, -45.6 % (-50.6 to -40.5) for US IMGs, and -56.6 % (-61.5 to -51.6) for non-US IMGs. Similarly, each non-MD applicant type had a lower adjusted percent difference in matching than MD seniors across almost all Step 1 score ranges, except for DO seniors with Step 1 scores <200 (-2.0 % [-9.5 to 5.5]). CONCLUSIONS: After adjusting for specialty choice, Step 1 score, and match year, non-US MD applicants had lower probabilities of matching into their preferred specialties than their US MD colleagues.

Multi-session transcutaneous spinal cord stimulation prevents chloride homeostasis imbalance and the development of hyperreflexia after spinal cord injury in rat.

Spasticity is a complex and multidimensional disorder that impacts nearly 75% of individuals with spinal cord injury (SCI) and currently lacks adequate treatment options. This sensorimotor condition is burdensome as hyperexcitability of reflex pathways result in exacerbated reflex responses, co-contractions of antagonistic muscles, and involuntary movements. Transcutaneous spinal cord stimulation (tSCS) has become a popular tool in the human SCI research field. The likeliness for this intervention to be successful as a noninvasive anti-spastic therapy after SCI is suggested by a mild and transitory improvement in spastic symptoms following a single stimulation session, but it remains to be determined if repeated tSCS over the course of weeks can produce more profound effects. Despite its popularity, the neuroplasticity induced by tSCS also remains widely unexplored, particularly due to the lack of suitable animal models to investigate this intervention. Thus, the basis of this work was to use tSCS over multiple sessions (multi-session tSCS) in a rat model to target spasticity after SCI and identify the long-term physiological improvements and anatomical neuroplasticity occurring in the spinal cord. Here, we show that multi-session tSCS in rats with an incomplete (severe T9 contusion) SCI (1) decreases hyperreflexia, (2) increases the low frequency-dependent modulation of the H-reflex, (3) prevents potassium-chloride cotransporter isoform 2 (KCC2) membrane downregulation in lumbar motoneurons, and (4) generally augments motor output, i.e., EMG amplitude in response to single pulses of tSCS, particularly in extensor muscles. Together, this work displays that multi-session tSCS can target and diminish spasticity after SCI as an alternative to pharmacological interventions and begins to highlight the underlying neuroplasticity contributing to its success in improving functional recovery.

Meniscus Tear Requiring Intraoperative Repair Does Not Influence Midterm Patient-Reported Outcomes in Operatively Treated Tibial Plateau Fractures.

OBJECTIVES: Evaluate whether intraoperatively repaired lateral meniscus injuries impact midterm patient-reported outcomes in those undergoing operative fixation of tibial plateau fracture. DESIGN: Retrospective cohort study. SETTING: Level I trauma center. PATIENT SELECTION CRITERIA: All patients (n = 207) who underwent operative fixation of a tibial plateau fracture from 2016 to 2021 with a minimum of 10-month follow-up. OUTCOME MEASURES AND COMPARISONS: The Patient-Reported Outcomes Measurement Information System Physical Function, Knee Injury and Osteoarthritis Outcome Score, and the PROMIS-Preference health utility score. RESULTS: Overall, 207 patients were included with average follow-up of 2.9 years. Seventy-three patients (35%) underwent intraoperative lateral meniscus repair. Gender, age, body mass index, Charlson comorbidity index, days to surgery, ligamentous knee injury, open fracture, vascular injury, polytraumatic injuries, Schatzker classification, and Orthopaedic Trauma Association classification were not associated with meniscal repair ( P > 0.05). Rates of reoperation (42% vs. 31%, P = 0.11), infection (8% vs. 10%, P = 0.60), return to work (78% vs. 75%, P = 0.73), and subsequent total knee arthroplasty (8% vs. 5%, P = 0.39) were also similar between those who had a meniscal repair and those without a meniscal injury, respectively. There was no difference in Patient-Reported Outcomes Measurement Information System Physical Function (46.3 vs. 45.8, P = 0.707), PROMIS-Preference (0.51 vs. 0.50, P = 0.729), and all Knee Injury and Osteoarthritis Outcome Score domain scores at the final follow-up between those who had a meniscal repair and those without a meniscal injury, respectively. CONCLUSIONS: In patients with an operatively treated tibial plateau fracture, the presence of a concomitant intraoperatively identified and repaired lateral meniscal tear results in similar midterm PROMs and complication rates when compared with patients without meniscal injury. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Analysis of acute extremity compartment syndrome using a genealogic population database.

INTRODUCTION: Acute extremity compartment syndrome ("CS") is an under-researched, highly morbid condition affecting trauma populations. The purpose of this study was to analyze incidence rates and risk factors for extremity compartment syndrome using a high-quality population database. Additionally, we evaluated heritable risk for CS using available genealogic data. We hypothesized that diagnosis of extremity compartment syndrome would demonstrate heritability. MATERIALS AND METHODS: Adult patients with fractures of the tibia, femur, and upper extremity were retrospectively identified by ICD-9, ICD-10, and CPT codes from 1996 to 2020 in a statewide hospital database. Exposed and unexposed cohorts were created based on a diagnosis of CS. Available demographic data were analyzed to determine risk factors for compartment syndrome using logistic regression. Mortality risk at the final follow-up was evaluated using Cox proportional hazard modeling. Patients with a diagnosis of CS were matched with those without a diagnosis for heritability analysis. RESULTS: Of 158,624 fractures, 931 patients were diagnosed with CS. Incidence of CS was 0.59% (tibia 0.83%, femur 0.31%, upper extremity 0.27%). Male sex (78.1% vs. 46.4%; p < 0.001; RR = 3.24), younger age at fracture (38.8 vs. 48.0 years; p < 0.001; RR = 0.74), Medicaid enrollment (13.2% vs. 9.3%; p < 0.001; RR = 1.58), and smoking (41.1% vs. 31.1%; p < 0.001; RR 1.67) were significant risk factors for CS. CS was associated with mortality (RR 1.61, p < 0.001) at mean follow-up 8.9 years in the CS cohort. No significant heritable risk was found for diagnosis of CS. CONCLUSIONS: Without isolating high-risk fractures, rates of CS are lower than previously reported in the literature. Male sex, younger age, smoking, and Medicaid enrollment were independent risk factors for CS. CS increased mortality risk at long-term follow-up. No heritable risk was found for CS. LEVEL OF EVIDENCE: III.

Establishing the Patient Acceptable Symptom State Thresholds for Patient-Reported Outcomes after Operatively Treated Tibial Plateau Fractures.

OBJECTIVES: Define patient-acceptable symptom state (PASS) thresholds and factors affecting PASS thresholds for Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Knee Injury and Osteoarthritis Outcome Score (KOOS) following operatively treated tibial plateau fractures. DESIGN: Retrospective cohort. SETTING: Single Level I academic trauma center. PATIENT SELECTION CRITERIA: All patients (n = 159) who underwent fixation of a tibial plateau fracture from 2016 to 2021 and completed patient-reported outcome measures (PROMs) at minimum 1-year follow-up were enrolled for the study. OUTCOME MEASURES AND COMPARISONS: PASS thresholds for global outcome (PASS-Global), pain (PASS-Pain), and function (PASS-Function) were determined using anchor-based questions such as "How satisfied are you today with your injured lower extremity?" with answer choices of very satisfied, satisfied, neutral, unsatisfied, and very unsatisfied. PASS thresholds for each PROM were calculated using 3 methods: (1) 80% specificity, (2) 75th percentile, and (3) Youden Index. RESULTS: Sixty percent of patients were satisfied with their global outcome and 53% with function. Using 80% specificity, 75th percentile, and Youden Index, PASS-Global thresholds were 48.5, 44.5, and 47.9 for PROMIS-PF and 56.3, 56.2, and 56.3 for KOOS-QOL, respectively. PASS-Pain threshold for KOOS-Pain was 84.4, 80.6, and 80.6, respectively. PASS-Function thresholds were 48.9, 46.8, and 48 for PROMIS-PF and 94.1, 90.2, and 86.8 for KOOS-ADL, respectively. Younger patients and those with bicondylar fractures or infections were associated with significantly lower PASS-Pain thresholds. Schatzker II fractures, lateral column involvement, or isolated lateral approach resulted in significantly higher PASS-Global and PASS-Function thresholds. CONCLUSIONS: This study defines global, functional, and pain PASS thresholds for tibial plateau fractures. Patients with bicondylar fractures, infections, and medial column involvement were more often unsatisfied. These thresholds are valuable references to identify patients who have attained satisfactory outcomes and to counsel patients with risk factors for unsatisfactory outcomes following tibial plateau fractures. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Worse Quality of Life Associated With Hyperextension Varus Tibial Plateau Fracture Pattern.

OBJECTIVES: Compare patient-reported outcome measures between hyperextension varus tibial plateau (HEVTP) fracture patterns to non-HEVTP fracture patterns. DESIGN: Retrospective study. SETTING: Single academic Level 1 Trauma Center. PATIENT SELECTION CRITERIA: All patients who underwent fixation of a tibial plateau fracture from 2016 to 2021 were collected. Exclusion criteria included inaccurate Current Procedural Terminology code, ipsilateral compartment syndrome, bilateral fractures, incomplete medical records, or follow-up <10 months. OUTCOME MEASURES AND COMPARISONS: In patients who underwent fixation of a tibial plateau fracture, compare Patient-Reported Outcomes Measurement Information System-Physical Function, PROMIS Preference, and Knee Injury and Osteoarthritis Outcome Score (KOOS) between patients with a HEVTP pattern with those without. RESULTS: Two-hundred and seven patients were included, of which 17 (8%) had HEVTP fractures. Compared with non-HEVTP fracture patterns, patients with HEVTP injuries were younger (42.6 vs. 51.0, P = 0.025), more commonly male (71% vs. 44%, P = 0.033), and had higher body mass index (32.8 vs. 28.0, P = 0.05). HEVTP fractures had significantly more ligamentous knee (29% vs. 6%, P = 0.007) and vascular (12% vs. 1%, P = 0.035) injuries. Patient-Reported Outcomes Measurement Information System-Physical Function scores were similar between groups; however, PROMIS-Preference (0.37 vs. 0.51, P = 0.017) was significantly lower in HEVTP fractures. KOOS pain, activities of daily living, and quality-of-life scores were statistically lower in HEVTP fractures, but only KOOS quality-of-life was clinically relevant (41.7 vs. 59.3, P = 0.004). CONCLUSIONS: The HEVTP fracture pattern, whether unicondylar or bicondylar, was associated with a higher rate of ligamentous and vascular injuries compared with non-HEVTP fracture patterns. They were also associated with worse health-related quality of life at midterm follow-up. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

High-throughput quantification of red blood cell deformability and oxygen saturation to probe mechanisms of sickle cell disease.

The complex, systemic pathology of sickle cell disease is driven by multiple mechanisms including red blood cells (RBCs) stiffened by polymerized fibers of deoxygenated sickle hemoglobin. A critical step toward understanding the pathologic role of polymer-containing RBCs is quantifying the biophysical changes in these cells in physiologically relevant oxygen environments. We have developed a microfluidic platform capable of simultaneously measuring single RBC deformability and oxygen saturation under controlled oxygen and shear stress. We found that RBCs with detectable amounts of polymer have decreased oxygen affinity and decreased deformability. Surprisingly, the deformability of the polymer-containing cells is oxygen-independent, while the fraction of these cells increases as oxygen decreases. We also find that some fraction of these cells is present at most physiologic oxygen tensions, suggesting a role for these cells in the systemic pathologies. Additionally, the ability to measure these pathological cells should provide clearer targets for evaluating therapies.

Multi-session transcutaneous spinal cord stimulation prevents chloridehomeostasis imbalance and the development of spasticity after spinal cordinjury in rat.

Spasticity is a complex and multidimensional disorder that impacts nearly 75% of individuals with spinal cord injury (SCI) and currently lacks adequate treatment options. This sensorimotor condition is burdensome as hyperexcitability of reflex pathways result in exacerbated reflex responses, co-contractions of antagonistic muscles, and involuntary movements. Transcutaneous spinal cord stimulation (tSCS) has become a popular tool in the human SCI research field. The likeliness for this intervention to be successful as a noninvasive anti-spastic therapy after SCI is suggested by a mild and transitory improvement in spastic symptoms following a single stimulation session, but it remains to be determined if repeated tSCS over the course of weeks can produce more profound effects. Despite its popularity, the neuroplasticity induced by tSCS also remains widely unexplored, particularly due to the lack of suitable animal models to investigate this intervention. Thus, the basis of this work was to use tSCS over multiple sessions (multi-session tSCS) in a rat model to target spasticity after SCI and identify the long-term physiological improvements and anatomical neuroplasticity occurring in the spinal cord. Here, we show that multi-session tSCS in rats with an incomplete (severe T9 contusion) SCI (1) decreases hyperreflexia, (2) increases the low frequency-dependent modulation of the H-reflex, (3) prevents potassium-chloride cotransporter isoform 2 (KCC2) membrane downregulation in lumbar motoneurons, and (4) generally augments motor output, i.e., EMG amplitude in response to single pulses of tSCS, particularly in extensor muscles. Together, this work displays that multi-session tSCS can target and diminish spasticity after SCI as an alternative to pharmacological interventions and begins to highlight the underlying neuroplasticity contributing to its success in improving functional recovery.

Return to Skiing After Tibial Plateau Fracture.

Background: Tibial plateau fractures in skiers are devastating injuries with increasing incidence. Few studies have evaluated patient-reported outcomes and return to skiing after operative fixation of a tibial plateau fracture. Purpose: To (1) identify demographic factors, fracture characteristics, and patient-reported outcome measures that are associated with return to skiing and (2) characterize changes in skiing performance after operative fixation of a tibial plateau fracture. Study Design: Case series; Level of evidence, 4. Methods: We reviewed all operative tibial plateau fractures performed between 2016 and 2021 at a single level-1 trauma center. Patients with a minimum of 10-month follow-up data were included. Patients who self-identified as skiers or were injured skiing were divided into those who returned to skiing and those who did not postoperatively. Patients were contacted to complete the Patient-Reported Outcomes Measurement Information System-Physical Function domain (PROMIS-PF), the Knee injury and Osteoarthritis Outcome Score-Activities of Living (KOOS-ADL), and a custom return-to-skiing questionnaire. Multivariate logistic regression was performed with sex, injury while skiing, PROMIS-PF, and KOOS-ADL as covariates to evaluate factors predictive of return to skiing. Results: A total of 90 skiers with a mean follow-up of 3.4 ± 1.5 years were included in the analysis. The rate of return to skiing was 45.6% (n = 41). The return cohort was significantly more likely to be men (66% vs 41%; P = .018) and injured while skiing (63% vs 39%; P = .020). In the return cohort, 51.2% returned to skiing 12 months postoperatively. The percentage of patients who self-reported skiing on expert terrain dropped by half from pre- to postinjury (61% vs 29.3%, respectively). Only 78% of return skiers had regained comfort with skiing at the final follow-up. Most patients (65%) felt the hardest aspect of returning to skiing was psychological. In the multivariate regression, the male sex and KOOS-ADL independently predicted return to skiing (P = .006 and P = .028, respectively). Conclusion: Fewer than half of skiers who underwent operative fixation of a tibial plateau fracture could return to skiing at a mean 3-year follow-up. The knee-specific KOOS-ADL outperformed the global PROMIS-PF in predicting a return to skiing.

A machine learning approach to improve implementation monitoring of family-based preventive interventions in primary care.

Background: Evidence-based parenting programs effectively prevent the onset and escalation of child and adolescent behavioral health problems. When programs have been taken to scale, declines in the quality of implementation diminish intervention effects. Gold-standard methods of implementation monitoring are cost-prohibitive and impractical in resource-scarce delivery systems. Technological developments using computational linguistics and machine learning offer an opportunity to assess fidelity in a low burden, timely, and comprehensive manner. Methods: In this study, we test two natural language processing (NLP) methods [i.e., Term Frequency-Inverse Document Frequency (TF-IDF) and Bidirectional Encoder Representations from Transformers (BERT)] to assess the delivery of the Family Check-Up 4 Health (FCU4Health) program in a type 2 hybrid effectiveness-implementation trial conducted in primary care settings that serve primarily Latino families. We trained and evaluated models using 116 English and 81 Spanish-language transcripts from the 113 families who initiated FCU4Health services. We evaluated the concurrent validity of the TF-IDF and BERT models using observer ratings of program sessions using the COACH measure of competent adherence. Following the Implementation Cascade model, we assessed predictive validity using multiple indicators of parent engagement, which have been demonstrated to predict improvements in parenting and child outcomes. Results: Both TF-IDF and BERT ratings were significantly associated with observer ratings and engagement outcomes. Using mean squared error, results demonstrated improvement over baseline for observer ratings from a range of 0.83-1.02 to 0.62-0.76, resulting in an average improvement of 24%. Similarly, results demonstrated improvement over baseline for parent engagement indicators from a range of 0.81-27.3 to 0.62-19.50, resulting in an approximate average improvement of 18%. Conclusions: These results demonstrate the potential for NLP methods to assess implementation in evidence-based parenting programs delivered at scale. Future directions are presented. Trial registration: NCT03013309 ClinicalTrials.gov.

Research has shown that evidence-based parenting programs effectively prevent the onset and escalation of child and adolescent behavioral health problems. However, if they are not implemented with fidelity, there is a potential that they will not produce the same effects. Gold-standard methods of implementation monitoring include observations of program sessions. This is expensive and difficult to implement in delivery settings with limited resources. Using data from a trial of the Family Check-Up 4 Health program in primary care settings that served Latino families, we investigated the potential to make use of a form of machine learning called natural language processing (NLP) to monitor program delivery. NLP-based ratings were significantly associated with independent observer ratings of fidelity and participant engagement outcomes. These results demonstrate the potential for NLP methods to monitor implementation in evidence-based parenting programs delivered at scale.

Familial Analysis of Nonunion in a Genealogic Population Database Demonstrates No Evidence of Heritable Risk.

OBJECTIVE: To determine whether there is evidence of heritable risk for nonunion using a large, state-wide population database. DESIGN: Database. SETTING: Level 1 Trauma Center. POPULATION: All Utah residents from 1996 to 2021 who sustained a long bone fracture and their family members were included. OUTCOMES: The primary outcome was nonunion and the prevalence of nonunion among the patients' first-, second-, and third-degree relatives. The secondary objective was to identify demographic, injury, and socioeconomic risk factors associated with nonunion. RESULTS: In total, 150,263 fractures and 6577 nonunions (4.4%) were identified. This was highly refined to a 1:3 matched cohort of 4667 nonunions of 13,981 fractures for familial clustering analysis. Cox proportional hazards did not demonstrate excessive risk of nonunion among first- ( P = 0.863), second- ( P = 0.509), and third-degree relatives ( P = 0.252). Further analysis of the entire cohort demonstrated that male sex (relative risk [RR] = 1.15; P < 0.001), Medicaid enrollment (RR = 2.64; P < 0.001), open fracture (RR = 2.53; P < 0.001), age group 41-60 years (RR = 1.43; P < 0.001), and a history of obesity (RR = 1.20; P < 0.001) were independent risk factors for nonunion. CONCLUSIONS: Our results demonstrate no evidence of heritable risk for nonunion. Independent risk factors for nonunion were male sex, Medicaid enrollment, open fracture, middle age, and a history of obesity. Although it is important to identify modifiable and nonmodifiable risk factors, these results continue to support that the risk of nonunion is multifactorial, relating to injury characteristics, operative techniques, and patient-specific risk factors. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Tibial Plateau Fractures Complicated by Compartment Syndrome Are Associated With a 3 Times Higher Cost of Care.

OBJECTIVES: To determine the impact of acute compartment syndrome (ACS) and identify cost drivers of 1-year total treatment costs for operative tibial plateau fractures. DESIGN: Retrospective review. SETTING: Level 1 trauma center. PATIENTS: 337 patients with tibial plateau fractures, 24 of which were complicated by ACS. OUTCOMES: The primary outcome was total treatment cost over the first year for operatively treated tibial plateau fractures. The secondary objective was to use regression analysis to identify significant cost drivers. RESULTS: The diagnosis of ACS was associated with 2.85 times higher total treatment cost ( P < 0.001). ACS demonstrated increased total treatment cost when controlling for polytrauma ( P < 0.001) and postoperative infection ( P < 0.001). Regression analysis identified 5 variables significantly associated with total cost of care: body mass index, injury severity score, ACS, staged external fixation, and locking fixation ( P < 0.001; R 2 = 0.57). The diagnosis of ACS had the largest impact on total cost with a 3.5× greater impact on cost compared with the next highest variable, staged external fixation. CONCLUSIONS: Tibial plateau fractures complicated by ACS are associated with 2.85 times higher treatment costs over a 1-year period. There were 5 significant variables identified by regression analysis with ACS having the highest impact on total treatment. Together, these 5 factors account for 57% of treatment cost variability. LEVEL OF EVIDENCE: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hip Joint Venting Decreases the Traction Force Required to Access the Central Compartment During Hip Arthroscopy.

Purpose: To investigate the effect of hip joint venting on the magnitude of traction force required to arthroscopically access the central compartment of the hip. Methods: Patients who underwent hip arthroscopy for femoroacetabular impingement syndrome prospectively underwent an intraoperative traction protocol. Joint space was measured on fluoroscopic images obtained at 50 and 100 lbs of axial traction in the prevented and vented state, and joint space values were normalized to millimetric values using preoperative anteroposterior pelvis radiographs. Venting was performed by inserting a large gauge spinal needle into the hip joint through the hip capsule and removing the stylet. Joint space differences were compared with paired t-tests, Wilcoxon signed-rank tests, and McNemar tests. Results: Fifty hips in 46 patients were included. Mean joint space before venting was 7.4 ± 2.6 mm and 13.3 ± 2.8 mm at 50 and 100 lbs of traction, respectively. Mean joint space after venting was 13.9 ± 2.3 mm and 15.5 ± 2.4 mm at 50 and 100 lbs of traction, respectively. Mean differences in joint space at 50 and 100 lbs were 6.5 mm (P < .001) and 2.2 mm (P < .001), respectively. Mean joint space at 50 lbs in the vented state was significantly greater than in the pre-vented state at 100 lbs (13.9 mm vs. 13.3 mm; P = .002). The increase in joint space between 50 and 100 lbs of traction was significantly greater in the prevented state than in the vented state (5.9 mm vs 1.6 mm; P = .021). Conclusions: Venting the hip reduces the traction force necessary to arthroscopically visualize and instrument the central compartment of the hip by at least 50%. Further, residual negative pressurization of the hip joint remains after breaking the labral suction seal and venting effectively eliminates this phenomenon to aid in hip joint distraction at lower traction force. Level of Evidence: Level IV, case series.

Resurgence of Omicron BA.2 in SARS-CoV-2 infection-naive Hong Kong.

Hong Kong experienced a surge of Omicron BA.2 infections in early 2022, resulting in one of the highest per-capita death rates of COVID-19. The outbreak occurred in a dense population with low immunity towards natural SARS-CoV-2 infection, high vaccine hesitancy in vulnerable populations, comprehensive disease surveillance and the capacity for stringent public health and social measures (PHSMs). By analyzing genome sequences and epidemiological data, we reconstructed the epidemic trajectory of BA.2 wave and found that the initial BA.2 community transmission emerged from cross-infection within hotel quarantine. The rapid implementation of PHSMs suppressed early epidemic growth but the effective reproduction number (Re) increased again during the Spring festival in early February and remained around 1 until early April. Independent estimates of point prevalence and incidence using phylodynamics also showed extensive superspreading at this time, which likely contributed to the rapid expansion of the epidemic. Discordant inferences based on genomic and epidemiological data underscore the need for research to improve near real-time epidemic growth estimates by combining multiple disparate data sources to better inform outbreak response policy.

Residential Clustering of Coronavirus Disease 2019 Cases and Efficiency of Building-Wide Compulsory Testing Notices as a Transmission Control Measure in Hong Kong.

We described the frequency of residential case clusters and the efficiency of compulsory testing in identifying cases using buildings targeted in compulsory testing and locally infected coronavirus disease 2019 (COVID-19) cases matched by residence in Hong Kong. Most of the buildings (4246 of 7688, 55.2%) with COVID-19 cases identified had only 1 reported case, and 13% of the daily reported cases were detected through compulsory testing. Compulsory testing notices could be essential in attempting to eliminate infections ("zero COVID") and have an impact early in an epidemic, but they appear to be relatively inefficient in response to sustained community transmission.

Electronic Excitation Response of DNA to High-Energy Proton Radiation in Water.

The lack of molecular-level understanding for the electronic excitation response of DNA to charged particle radiation, such as high-energy protons, remains a fundamental scientific bottleneck in advancing proton and other ion beam cancer therapies. In particular, the dependence of different types of DNA damage on high-energy protons represents a significant knowledge void. Here we employ first-principles real-time time-dependent density functional theory simulation, using a massively parallel supercomputer, to unravel the quantum-mechanical details of the energy transfer from high-energy protons to DNA in water. The calculations reveal that protons deposit significantly more energy onto the DNA sugar-phosphate side chains than onto the nucleobases, and greater energy transfer is expected onto the DNA side chains than onto water. As a result of this electronic stopping process, highly energetic holes are generated on the DNA side chains as a source of oxidative damage.

Current Status of Perioperative Therapy in Muscle-Invasive Bladder Cancer and Future Directions.

PURPOSE OF REVIEW: Cisplatin-based combination chemotherapy has been a standard of care in the perioperative management of muscle-invasive bladder cancer for years, but several novel therapies are under active investigation. This review aims to provide an update on recent relevant literature and a forward look at the future landscape of adjuvant and neoadjuvant therapy in muscle-invasive bladder cancer patients who opt for radical cystectomy. RECENT FINDINGS: The recent approval of nivolumab as adjuvant therapy established a new treatment option for high-risk patients with muscle-invasive bladder cancer after radical cystectomy. Several phase II studies of chemo-immunotherapy combinations and immunotherapy alone have reported pathological complete responses in the 26-46% range, including studies in cisplatin-ineligible patients. Randomized studies of perioperative chemo-immunotherapy, immunotherapy alone, and enfortumab vedotin are ongoing. Muscle-invasive bladder cancer remains a challenging disease associated with significant morbidity and mortality; however, increasing options in systemic therapy and an increasingly personalized approach to cancer treatment suggest continued future improvements in patient care.