A missed opportunity: A scoping review of the effect of sex and age on osteoarthritis using large animal models.

OBJECTIVE: The objective was to critically analyze the published literature accounting for sex differences and skeletal age (open vs. closed physis) in preclinical animal models of OA, including the disaggregation of data by sex and skeletal maturity when data is generated from combined sex and/or multi-aged cohorts without proper confounding. METHOD: A scoping literature review of PubMed, Web of Science, EMBASE, and SCOPUS was performed for studies evaluating the effect of sex and age in experimental studies and clinical trials utilizing preclinical large animal models of OA. RESULTS: A total of 9727 papers were identified in large animal (dog, pig, sheep, goat, horse) models for preclinical OA research, of which 238 ex vivo and/or in vivo studies disclosed model type, animal species, sex, and skeletal age sufficient to analyze their effect on outcomes. Dogs, followed by pigs, sheep, and horses, were the most commonly used models. A paucity of preclinical studies evaluated the effect of sex and age in large animal models of naturally occurring or experimentally induced OA: 26 total studies reported some kind of analysis of the effects of sex or age, with 4 studies discussing the effects of sex only, 11 studies discussing the effects of age only, and 11 studies analyzing both the effects of age and sex. CONCLUSION: Fundamental to translational research, OARSI is uniquely positioned to develop recommendations for conducting preclinical studies using large animal models of OA that consider biological mechanisms linked to sex chromosomes, skeletal age, castration, and gonadal hormones affecting OA pathophysiology and treatment response.

Cationic tantalum oxide nanoparticle contrast agent for micro computed tomography reveals articular cartilage proteoglycan distribution and collagen architecture alterations.

OBJECTIVE: Cationic tantalum oxide nanoparticles (Ta2O5-cNPs), as a newly introduced contrast agent for computed tomography of cartilage, offer quantitative evaluation of proteoglycan (PG) content and biomechanical properties. However, knowledge on the depth-wise impact of cartilage constituents on nanoparticle diffusion, particularly the influence of the collagen network, is lacking. In this study, we aim to establish the depth-dependent relationship between Ta2O5-cNP diffusion and cartilage constituents (PG content, collagen content and network architecture). METHODS: Osteochondral samples (n = 30) were harvested from healthy equine stifle joints (N = 15) and the diffusion of 2.55 nm diameter cationic Ta2O5-cNPs into the cartilage was followed with micro computed tomography (µCT) imaging for up to 96 hours. The diffusion-related parameters, Ta2O5-cNP maximum partition (Pmax) and diffusion time constant, were compared against biomechanical and depth-wise structural properties. Biomechanics were assessed using stress-relaxation and sinusoidal loading protocols, whereas PG content, collagen content and collagen network architecture were determined using digital densitometry, Fourier-transform infrared spectroscopy and polarized light microscopy, respectively. RESULTS: The Pmax correlates with the depth-wise distribution of PGs (bulk Spearman's ρ = 0.87, p < 0.001). More open collagen network architecture at the superficial zone enhances intake of Ta2O5-cNPs, but collagen content overall decreases the intake. The Pmax values correlate with the equilibrium modulus (ρ = 0.80, p < 0.001) of articular cartilage. CONCLUSION: This study establishes the feasibility of Ta2O5-cNPs for the precise and comprehensive identification of biomechanical and structural changes in articular cartilage via contrast-enhanced µCT.

Computed tomography-based structural rigidity analysis can assess tumor- and treatment-induced changes in rat bones with metastatic lesions.

BACKGROUND: Breast cancer (BrCa) is a predominant malignancy, with metastasis occurring in one in eight patients, nearly half of which target the bone, leading to serious complications such as pain, fractures, and compromised mobility. Structural rigidity, crucial for bone strength, becomes compromised with osteolytic lesions, highlighting the vulnerability and increased fracture risk in affected areas. Historically, two-dimensional radiographs have been employed to predict these fracture risks; however, their limitations in capturing the three-dimensional structural and material changes in bone have raised concerns. Recent advances in CT-based Structural Rigidity Analysis (CTRA), offer a promising, more accurate non-invasive 3D approach. This study aims to assess the efficacy of CTRA in monitoring osteolytic lesions' progression and response to therapy, suggesting its potential superiority over existing methodologies in guiding treatment strategies. METHODS: Twenty-seven female nude rats underwent femoral intra-medullary inoculation with MDA-MB-231 human breast cancer cells or saline control. They were divided into Control, Cancer Control, Ibandronate, and Paclitaxel groups. Osteolytic progression was monitored weekly using biplanar radiography, quantitative computed tomography (QCT), and dual-energy X-ray absorptiometry (DEXA). CTRA was employed to predict fracture risk, normalized using the contralateral femur. Statistical analyses, including Kruskal-Wallis and ANOVA, assessed differences in outcomes among groups and over time. RESULTS: Biplanar radiographs showed treatment benefits over time; however, only certain time-specific differences between the Control and other treatment groups were discernible. Notably, observer subjectivity in X-ray scoring became evident, with significant inter-operator variations. DEXA measurements for metaphyseal Bone Mineral Content (BMC) did not exhibit notable differences between groups. Although diaphyseal BMC highlighted some variance, it did not reveal significant differences between treatments at specific time points, suggesting a limited ability for DEXA to differentiate between treatment effects. In contrast, the CTRA consistently demonstrated variations across different treatments, effectively capturing bone rigidity changes over time, and the axial- (EA), bending- (EI), and torsional rigidity (GJ) outcomes from the CTRA method successfully distinguished differences among treatments at specific time points. CONCLUSION: Traditional approaches, such as biplanar radiographs and DEXA, have exhibited inherent limitations, notably observer bias and time-specific inefficacies. Our study accentuates the capability of CTRA in capturing real-time, progressive changes in bone structure, with the potential to predict fractures more accurately and provide a more objective analysis. Ultimately, this innovative approach may bridge the existing gap in clinical guidelines, ushering in enhanced Clinical Decision Support Tool (CDST) for both surgical and non-surgical treatments.

Quantitative 1H Magnetic Resonance Imaging on Normal and Pathologic Rat Bones by Solid-State 1H ZTE Sequence with Water and Fat Suppression.

BACKGROUND: Osteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo. PURPOSE: To demonstrate water + fat suppressed 1H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model. STUDY TYPE: Prospective. ANIMAL MODEL: Fifteen skeletally mature female Sprague-Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit-D) deficient), 250-275 g, ∼15 weeks old. FIELD STRENGTH/SEQUENCE: 7T, zero echo time sequence with water + fat (VAPOR) suppression capability, µCT imaging, and gravimetric measurements. ASSESSMENT: Cortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density. STATISTICAL TESTS: ANOVA and linear regression were used for data analysis, with P-values <0.05 statistically significant. RESULTS: The MRI-derived three-density PEG pellet densities have a strong linear relationship with physical density measures (r2 = 0.99). The Vit-D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm-3), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm-3). Gravimetry results confirmed these MRI-based observations for Vit-D cortical (0.51 ± 0.07 g cm-3) and OVX trabecular (0.26 ± 0.03 g cm-3) bone groups. DATA CONCLUSION: Rat femur images were obtained using a modified pulse sequence and a custom-designed double-tuned (1H/31P) transmit-receive solenoid-coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI-derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit-D deficient/partially nephrectomized animals were computed. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Evaluation of musculoskeletal phenotype of the G608G progeria mouse model with lonafarnib, pravastatin, and zoledronic acid as treatment groups.

Hutchinson-Gilford progeria syndrome (HGPS) is a uniformly fatal condition that is especially prevalent in skin, cardiovascular, and musculoskeletal systems. A wide gap exists between our knowledge of the disease and a promising treatment or cure. The aim of this study was to first characterize the musculoskeletal phenotype of the homozygous G608G BAC-transgenic progeria mouse model, and to determine the phenotype changes of HGPS mice after a five-arm preclinical trial of different treatment combinations with lonafarnib, pravastatin, and zoledronic acid. Microcomputed tomography and CT-based rigidity analyses were performed to assess cortical and trabecular bone structure, density, and rigidity. Bones were loaded to failure with three-point bending to assess strength. Contrast-enhanced µCT imaging of mouse femurs was performed to measure glycosaminoglycan content, thickness, and volume of the femoral head articular cartilage. Advanced glycation end products were assessed with a fluorometric assay. The changes demonstrated in the cortical bone structure, rigidity, stiffness, and modulus of the HGPS G608G mouse model may increase the risk for bending and deformation, which could result in the skeletal dysplasia characteristic of HGPS. Cartilage abnormalities seen in this HGPS model resemble changes observed in the age-matched WT controls, including early loss of glycosaminoglycans, and decreased cartilage thickness and volume. Such changes might mimic prevalent degenerative joint diseases in the elderly. Lonafarnib monotherapy did not improve bone or cartilage parameters, but treatment combinations with pravastatin and zoledronic acid significantly improved bone structure and mechanical properties and cartilage structural parameters, which ameliorate the musculoskeletal phenotype of the disease.

Parental caregivers' perception of their transition from hospital to home in children with cerebral palsy who have undergone orthopedic surgery.

PURPOSE: Evaluate parental perception of the quality of discharge teaching, readiness for discharge, and the impact of these on post discharge coping difficulty and resource utilization in children with cerebral palsy (CP) following surgery. DESIGN AND METHODS: Prospective cohort study conducted from September 2017-March 2021 at a pediatric academic medical center. Demographics were collected pre-operatively. Parents completed the Readiness for Hospital Discharge Scale (RHDS) and Quality of Discharge Teaching Scale (QDTS) within four hours of discharge. Four weeks post-discharge, parents completed the Post-discharge Coping Difficulty Scale (PDCDS). Utilization of healthcare resources were extracted from the electronic health record for 90 days post-operatively. Associations among demographics, RHDS, QDTS, PDCDS and resource utilization were assessed using general linear models; PDCDS's open-ended questions were analyzed using directed content analysis. RESULTS: 114 parental caregivers participated. Post discharge coping was significantly associated with additional resource utilization: length of stay (p = 0.046), readmissions (p = 0.001), emergency department visits (p = 0.001), clinic calls (p = 0.001) and unplanned clinic visits (p = 0.006). PDCDS was negatively correlated with the QDTS Quality of Teaching Delivered subscale (r = -0.32; p = 0.004) and three of five RHDS subscales: 1) Child's Personal Status (r = -0.24; p = 0.02); 2) Knowledge (r = -0.30; p = 0.005); and 3) Coping Ability (r = -0.39; p < 0.001). Four themes explicated parental coping difficulties. CONCLUSION: Parents experiencing coping difficulties were more likely to have difficulty managing their child's care needs at home and required additional health care resources. PRACTICE IMPLICATIONS: Recognizing that parents' readiness for discharge may not reflect their coping abilities post-discharge requiring nurses to coordinate pre- and post-discharge education and support services.

Health-related quality of life and caregiver burden after hip reconstruction and spinal fusion in children with spastic cerebral palsy.

AIM: To evaluate the effect of hip reconstruction or spinal fusion on health-related quality of life (HRQoL) in non-ambulatory children with spastic cerebral palsy (CP) and caregiver burden. METHOD: This was a prospective, longitudinal study of changes in HRQoL and caregiver burden over the 5 years after surgical correction of hip instability or scoliosis in children with bilateral spastic CP classified in Gross Motor Function Classification levels IV or V. Serial parent proxy measures of HRQoL and caregiver burden were obtained before and 6 weeks, and 3, 6, 9, 12, 24, and 60 months after surgery using the Caregiver Priorities and Child Health Index of Life with Disabilities and the Assessment of Caregiver Experience with Neuromuscular Disease. Scores 5 years or more after surgery were compared to pre-surgery scores using paired Student's t-tests. Serial outcome trajectories were estimated by linear mixed modeling. RESULTS: Of 69 participants (40 males, 29 females; mean age 11y 6mo, SD 4y 1mo, range 3y 10mo-20y 7mo), 43 had hip reconstruction and 26 had spinal fusion. Clinically significant improvements in HRQoL were detected (average increase 7.6 points) 5 years or more postoperatively, with hip reconstruction providing greater benefit. Domains improved by surgery included positioning, transferring/mobility, comfort/emotions, and health. Caregiver burden did not change as these children remain maximally dependent. INTERPRETATION: Surgical treatment of hip and spine deformity improves HRQoL, especially for painful hip instability, but does not change caregiver burden.

Management of arthrofibrosis in neuromuscular disorders: a review.

Arthrofibrosis, or rigid contracture of major articular joints, is a significant morbidity of many neurodegenerative disorders. The pathogenesis depends on the mechanism and severity of the precipitating neuromuscular disorder. Most neuromuscular disorders, whether spastic or hypotonic, culminate in decreased joint range of motion. Limited range of motion precipitates a cascade of pathophysiological changes in the muscle-tendon unit, the joint capsule, and the articular cartilage. Resulting joint contractures limit functional mobility, posing both physical and psychosocial burdens to patients, economic burdens on the healthcare system, and lost productivity to society. This article reviews the pathophysiology of arthrofibrosis in the setting of neuromuscular disorders. We describe current non-surgical and surgical interventions for treating arthrofibrosis of commonly affected joints. In addition, we preview several promising modalities under development to ameliorate arthrofibrosis non-surgically and discuss limitations in the field of arthrofibrosis secondary to neuromuscular disorders.

Mortality in Neuromuscular Early Onset Scoliosis Following Spinal Deformity Surgery.

BACKGROUND: The purpose of this study was to report mortality and associated risk factors in neuromuscular early onset scoliosis following spinal deformity surgery. METHODS: This is a multicenter retrospective cohort study of patients with cerebral palsy (CP), spinal muscular atrophy, myelodysplasia, muscular dystrophy, or myopathy undergoing index spine surgery from 1994 to 2020. Mortality risk was calculated up to 10 years postoperatively. Proportional hazard modeling was utilized to investigate associations between risk factors and mortality rate. RESULTS: A total of 808 patients [mean age 7.7 y; 439 (54.3%) female] were identified. Postoperative 30-day, 90-day, and 120-day mortality was 0%, 0.001%, and 0.01%, respectively. 1-year, 2-year, 5-year, and 10-year mortality was 0.5%, 1.1%, 5.4%, and 17.4%, respectively. Factors associated with increased mortality rate: CP diagnosis [hazard ratio (HR): 3.14, 95% confidence interval (CI): 1.71; 5.79, P<0.001]; nonambulatory status (HR: 3.01, 95% CI: 1.06; 8.5, P=0.04)]; need for respiratory assistance (HR: 2.17, 95% CI: 1.00; 4.69, P=0.05). CONCLUSIONS: In neuromuscular patients with early onset scoliosis, mortality risk at 10 years following spine surgery was 17.4%. As mortality was 1.1% at 2 years, premature death was unlikely a direct result of spine surgery. Diagnosis (CP) and markers of disease severity (nonambulatory status, respiratory assistance) were associated with increased mortality rate. LEVEL OF EVIDENCE: Prognostic level II.

Spinal Fusion in Pediatric Patients With Low Bone Density: Defining the Value of DXA.

BACKGROUND: Children with medical complexity are at increased risk of low bone mineral density (BMD) and complications after spinal fusion compared with idiopathic scoliosis patients. Our aim was to compare treatments and outcomes of children with medical complexity undergoing spinal fusion in those who had dual-energy x-ray absorptiometry (DXA) scans versus those who did not in an effort to standardize the workup of these patients before undergoing spinal surgery. METHODS: We conducted a retrospective review of patients with low BMD who underwent spinal fusion at a tertiary care pediatric hospital between 2004 and 2016. We consulted with a pediatric endocrinologist to create standard definitions for low BMD to classify each subject. Regardless of DXA status, all patients were given a clinical diagnosis of osteoporosis [at least 2 long bone or 1 vertebral pathologic fracture(s)], osteopenia (stated on radiograph or by the physician), or clinically low bone density belonging to neither category. The last classification was used for patients whose clinicians had documented low bone density not meeting the criteria for osteoporosis or osteopenia. Fifty-nine patients met the criteria, and 314 were excluded for insufficient follow-up and/or not meeting a diagnosis definition. BMD Z -scores compare bone density ascertained by DXA to an age-matched and sex-matched average. Patients who had a DXA scan were also given a DXA diagnosis of low bone density (≤-2 SD), slightly low bone density (-1.0 to -1.9 SD), or neither (>-1.0 SD) based on the lowest BMD Z -score recorded. RESULTS: Fifty-nine patients were analyzed. Fifty-four percent had at least 1 DXA scan preoperatively. Eighty-one percent of DXA patients received some form of treatment compared with 52% of non-DXA patients ( P =0.03). CONCLUSIONS: Patients referred for DXA scans were more likely to be treated for low BMD, although there is no standardized system in place to determine which patients should get scans. Our research highlights the need to implement clinical protocols to optimize bone health preoperatively. LEVEL OF EVIDENCE: Level II-retrospective prognostic study.

Barriers to Discharge After Hip Reconstruction Surgery in Non-ambulatory Children With Neurological Complex Chronic Conditions.

BACKGROUND: Hip reconstruction surgery in patients with neurological complex chronic conditions (CCC) is associated with prolonged hospitalization and extensive resource utilization. This population is vulnerable to cognitive, developmental, and medical comorbidities which can increase length of stay (LOS). The aims of this study were to characterize barriers to discharge for a cohort of children with neurological CCC undergoing hip reconstruction surgery and to identify patient risk factors for prolonged hospitalization and delayed discharge. METHODS: Retrospective chart review of nonambulatory patients with neurological CCC undergoing hip reconstruction surgery between 2007-2016 was conducted. Hospitalization ≥1 day past medical clearance was characterized as delayed discharge. Barriers were defined as unresolved issues at the time of medical clearance and categorized as pertaining to the caregiver and patient education, durable medical equipment, postdischarge transportation/placement, and patient care needs. RESULTS: The cohort of 116 patients was 53% male, 16% non-English speaking, and 49% Gross Motor Function Classification System (GMFCS) V with the mean age at surgery of 9.1±3.64 years. Median time from admission to medical clearance was 5 days with median LOS of 6 days. Approximately three-quarters of patients experienced delayed discharge (73%) with barriers identified for 74% of delays. Most prevalent barriers involved education (30%) and durable medical equipment (29%). Postdischarge transportation and placement accounted for 26% of barriers and 3.5 times longer delays ( P <0.001). Factors associated with delayed discharge included increased medical comorbidities ( P <0.05) and GMFCS V ( P <0.001). Longer LOS and medical clearance times were found for female ( P =0.005), older age ( P <0.001), bilateral surgery ( P =0.009), GMFCS V ( P =0.003), and non-English-speaking patients ( P <0.001). CONCLUSIONS: Patients with neurological CCC frequently encounter postoperative barriers contributing to increased LOS and delayed discharge. Patients that may be at higher risk for prolonged hospitalization and greater resource utilization include those who are female sex, adolescent, GMFCS V, non-English speaking, have additional comorbidities, and are undergoing bilateral surgery. Standardized preoperative assessment of educational needs, perioperative equipment requirements, and posthospital transportation may decrease the LOS, reduce caregiver and patient burden/distress, cost, and ultimately reduce variation in care delivery. LEVEL OF EVIDENCE: Level III, Retrospective Case Series.

Epidural Analgesia Versus Lumbar Plexus Blockade After Hip Reconstruction Surgery in Children With Cerebral Palsy and Intrathecal Baclofen Pumps: A Comparison of Safety and Efficacy.

BACKGROUND: Epidural analgesia is commonly used for pain control after reconstructive hip surgery, but its use is controversial in the presence of an intrathecal baclofen pump (ITB). The purpose of this retrospective study was to investigate the rate of serious anesthetic and postoperative complications as well as the efficacy of epidural analgesia compared with lumbar plexus blocks (LPBs) for pain management after neuromuscular hip reconstruction in children with cerebral palsy (CP) and ITB. METHODS: Pediatric patients with CP and ITB undergoing hip reconstructive surgery from 2010 to 2019 were retrospectively identified. Patients receiving epidural analgesia were compared with those receiving LPB. Morphine milligram equivalents per kilogram were used as a surrogate measure for pain-related outcomes, as pain scores were reported with wide ranges (eg, 0 to 5/10), making it unfeasible to compare them across the cohort. Postoperative complications were graded using the modified Clavien-Dindo classification. RESULTS: Forty-four patients (26/44, 59% male) underwent surgery at an average age of 10.3 years (SD=3.4 y, range: 4 to 17 y). The majority utilized LPB (28/44, 64%) while the remaining utilized epidural (16/44, 36%). There were no differences in rates of serious complications, including no cases of ITB malfunction, damage, or infection. During the immediate postoperative course, patients who received LPB had higher morphine milligram equivalents per kilogram requirements than patients who received epidural analgesia. CONCLUSIONS: In patients with CP undergoing hip reconstruction surgery with an ITB in situ, epidural anesthesia was associated with improved analgesia compared with LPB analgesia, with a similar risk for adverse outcomes. Epidural catheters placed using image-guided insertion techniques can avoid damage to the ITB catheter while providing effective postoperative pain control without increasing rates of complications in this complex patient population. LEVEL OF EVIDENCE: Level III.

Mortality in Early-Onset Scoliosis During the Growth-friendly Surgery Era.

INTRODUCTION: Early-onset scoliosis (EOS) is a spinal deformity that occurs in patients 9 years of age or younger. Severe deformity may result in thoracic insufficiency, respiratory failure, and premature death. The purpose of this study is to describe the modern-day natural history of mortality in patients with EOS. METHODS: The multicenter Pediatric Spine Study Group database was queried for all patients with EOS who are deceased, without exclusion. Demographics, underlying diagnoses, EOS etiology, operative and nonoperative treatments or observation, complications, and date of death were retrieved. Descriptive statistics and survival analysis with Kaplan-Meier curves were performed. RESULTS: There were 130/8009 patients identified as deceased for a registry mortality rate of 16 per 1000 patients. The mean age at death was 10.6 years (range: 1.0 to 30.2 y) and the most common EOS etiology was neuromuscular (73/130, 56.2%; P<0.001). Deceased patients were more likely be treated operatively than nonoperatively or observed (P<0.001). The mean age of death for patients treated operatively (12.3 y) was older than those treated nonoperatively (7.0 y) or observed (6.3 y) (P<0.001) despite a larger deformity and similar index visit body mass index and ventilation requirements. Kaplan-Meier analysis confirmed an increased survival time in patients with a history of any spine operation compared with patients without a history of spine operation (P<0.0001). Operatively treated patients experienced a median of 3.0 complications from diagnosis to death. Overall, cardiopulmonary related complications were the most common (129/271, 47.6%; P<0.001), followed by implant-related (57/271, 21.0%) and wound-related (26/271, 9.6%). The primary cause of death was identified for 78/130 (60.0%) patients, of which 57/78 (73.1%) were cardiopulmonary related. CONCLUSIONS: This study represents the largest collection of EOS mortality to date, providing surgeons with a modern-day examination of the effects of surgical intervention to better council patients and families. Both fatal and nonfatal complications in children with EOS are most likely to involve the cardiopulmonary system. LEVEL OF EVIDENCE: Level IV-therapeutic.

Variability in Antibiotic Treatment of Pediatric Surgical Site Infection After Spinal Fusion at A Single Institution.

BACKGROUND: Recent focus on surgical site infections (SSIs) after posterior spine fusion (PSF) has lowered infection rates by standardizing perioperative antibiotic prophylaxis. However, efforts have neglected to detail antibiotic treatment of SSIs. Our aim was to document variability in antibiotic regimens prescribed for acute and latent SSIs following PSF in children with idiopathic, neuromuscular, and syndromic scoliosis. METHODS: This study included patients who developed a SSI after PSF for scoliosis at a pediatric tertiary care hospital between 2004 and 2019. Patients had to be 21 years or younger at surgery. Exclusion criteria included growing rods, staged surgery, and revision or removal before SSI diagnosis. Infection was classified as acute (within 90 d) or latent. Clinical resolution of SSI was measured by return to normal lab values. Each antibiotic was categorized as empiric or tailored. RESULTS: Eighty subjects were identified. The average age at fusion was 14.7 years and 40% of the cohort was male. Most diagnoses were neuromuscular (53%) or idiopathic (41%).Sixty-three percent of patients had an acute infection and 88% had a deep infection. The majority (54%) of subjects began on tailored antibiotic therapy versus empiric (46%). Patients with a neuromuscular diagnosis had 4.0 times the odds of receiving initial empiric treatment compared with patients with an idiopathic diagnosis, controlling for infection type and time (P=0.01). Ninety-two percent of patients with acute SSI retained implants at the time of infection and 76% retained them as of August 2020. In the latent cohort, 27% retained implants at infection and 17% retained them as of August 2020. CONCLUSIONS: Patients with acute infections were on antibiotics longer than patients with latent infections. Those with retained implants were on antibiotics longer than those who underwent removal. By providing averages of antibiotic duration and lab normalization, we hope to standardize regimens moving forward and develop SSI-reducing pathways encompassing low-risk patients. LEVEL OF EVIDENCE: Level III.

Outcomes and Complications in Management of Congenital Myopathy Early-Onset Scoliosis.

BACKGROUND: Congenital myopathies (CMs) are complex conditions often associated with early-onset scoliosis (EOS). The purpose of this study was to investigate radiographic outcomes in CM patients undergoing EOS instrumentation as well as complications. Secondarily, we sought to compare these patients to a population with higher prevalence, cerebral palsy (CP) EOS patients. METHODS: This is a retrospective study of a prospectively collected multicenter registry. The registry was queried for EOS patients with growth-sparing instrumentation (vertical expandable prosthetic titanium ribs, magnetically controlled growing rods, traditional growing rod, or Shilla) and a CM or CP diagnosis with minimum 2 years follow-up. Outcomes included major curve magnitude, T1-S1 height, kyphosis, and complications. RESULTS: Sixteen patients with CM were included. Six (37.5%) children with CM experienced 11 complications by 2 years. Mean major curve magnitude for CM patients was improved postoperatively and maintained at 2 years (P<0.01), with no significant increase in T1-S1 height or maximum kyphosis(P>0.05). Ninety-seven patients with CP EOS were included as a comparative cohort. Fewer CP patients required baseline respiratory support compared with CM patients (20.0% vs. 92.9%, P<0.01). Fifty-four (55.7%) CP patients experienced a total of 105 complications at 2 years. There was no evidence that the risk of complication or radiographic outcomes differs between cohorts at 2 years, though CP EOS patients experienced significant improvement in all measurements at 2 years. CONCLUSIONS: EOS CM children face a high risk of complication after growing instrumentation, with similar curve correction and risk of complication to CP patients. LEVEL OF EVIDENCE: Level III.

A Large Discrepancy between Oral versus Rectal Temperatures as an Early Warning Sign in a Patient with Acute Infrarenal Aortic Occlusion.

BACKGROUND: Acute aortic occlusion is a rare condition that requires early diagnosis to help prevent considerable morbidity and mortality. Typical clinical findings, such as acute lower extremity pain, acute paralysis, and absent pedal pulses, may be masked by a variety of underlying medical conditions. CASE REPORT: We present a patient with altered mental status, hypothermia, and a large discrepancy between oral and rectal temperature measurements, who was ultimately diagnosed with aortic occlusion. This case report describes a marked difference between oral and rectal temperatures in a case of acute aortic occlusion. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Acute aortic occlusion is a true vascular emergency that, without early intervention, can lead to limb ischemia, bowel necrosis, paralysis, or death. Emergency physicians should consider acute aortic occlusion in a patient with a marked difference between oral and rectal temperature measurements who otherwise has a limited clinical evaluation.

Incidence of Pediatric Venous Thromboembolism After Elective Spine and Lower-Extremity Surgery in Children With Neuromuscular Complex Chronic Conditions: Do we Need Prophylaxis?

BACKGROUND: The incidence of venous thromboembolism (VTE) after elective surgery in children with mobility impairments, including those with a neuromuscular complex chronic condition (NCCC), is unknown. Therefore, our objectives were to assess the incidence of VTE after elective spine and lower-extremity surgery in children with NCCC. METHODS: A retrospective analysis of children with NCCC undergoing elective lower-extremity and/or spinal surgeries from 2005 to 2009 included in the Pediatric Health Information Systems Plus (PHIS+) database. VTE during hospitalization for surgery was assessed through abstraction and review of ultrasound (U/S) and computed tomography results by 2 independent reviewers. VTEs related to pre-existing central venous catheters were excluded. RESULTS: There were 4,583 children with NCCC who underwent orthopaedic surgery during the study period at 6 centers. Most were male (56.3%), non-Hispanic whites (72.7%), and had private insurance (52.2%). The most common NCCC diagnoses were cerebral palsy (46.7%), brain and spinal cord malformations (31.1%), and central nervous system degenerative conditions (14.5%). Forty children (0.9%) underwent U/S to assess VTE. Eighteen children (0.4%) underwent computed tomography to assess VTE. Four children (with cerebral palsy) had a positive U/S for a lower-extremity VTE (10-18 y of age), yet 2 had their VTE before surgery. Therefore, the adjusted VTE rate for children with NCCC undergoing orthopaedic lower-extremity or spine surgery was 4 per 10,000 (2 cases per 4583 surgeries). Each of the 2 cases had a known coagulation disorder preoperatively. Only 10% of the cohort used compression devices, 3% enoxaparin, and 1.6% aspirin for prophylaxis. CONCLUSION: The rate of non-central-venous-catheter-related VTE associated with orthopaedic surgery in children with NCCC is very low and lower than rates reported in healthy children. SIGNIFICANCE: To our knowledge, this is the first multi-institutional study reporting the incidence of VTE in children with NCCCs undergoing elective hip and spine surgery. These data support no additional prophylaxis is required in children with NCCC undergoing elective hip and spine surgery unless other known risk factors are also present.

Hip Reconstruction in Nonambulatory Children With Cerebral Palsy: Identifying Risk Factors Associated With Postoperative Complications and Prolonged Length of Stay.

BACKGROUND: The purpose of this study is to examine the relationship between preoperative comorbidities, surgical complications, and length of stay (LOS) after hip reconstruction in nonambulatory children with cerebral palsy (CP). METHODS: This single-center retrospective cohort study included 127 patients undergoing hip surgery between 2007 and 2016 who were diagnosed with CP (GMFCS IV/V). The cohort was 54% Gross Motor Function Classification System (GMFCS) V with an average age at surgery of 9 years (range, 3-19 y). Preoperative comorbidities included: presence of a gastrostomy tube, respiratory difficulty requiring positive-pressure ventilation or tracheostomy, history of seizures, and nonverbal status. Complications were dichotomized into major and minor complications according to severity. Multivariable general linear modeling was used to identify factors associated with complications and prolonged LOS. RESULTS: The median LOS in the hospital was 6 days (intequartile range, 5-9 d). The majority of procedures (72%) involved both the femur and acetabulum and 82% of surgeries were performed bilaterally. Patients who experienced a major complication were mostly GMFCS level V and were more likely to spend time in intensive care unit than postanesthetic care unit (P=0.001). Multivariable analysis for a major complication determined that the addition of each comorbid risk fact increased the odds of developing a major complication by 2.6 times (odds ratio, 2.64; 95% confidence interval, 1.56-4.47; P<0.001) regardless of GMFCS level. Multivariable analysis for prolonged LOS determined that major complications (P<0.001), bilaterality (P=0.01), age (P=0.02), female sex (P=0.01), and GMFCS V (P<0.001) were all factors that increased LOS. Migration percentage, acetabular index odds ratio, and pelvic obliquity were not associated with prolonged LOS or the presence of a major complication. CONCLUSIONS: From our analysis, the authors found that a patient's premorbid comorbidities were more predictive of the likelihood of sustaining a major complication than their GMFCS level. Identifying high-risk patients preoperatively may help reduce complications and LOS, which ultimately will improve the quality of care the authors deliver to nonambulatory children with CP undergoing hip reconstruction surgery. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

The Use of Tranexamic Acid (TXA) in Neuromuscular Hip Reconstruction: Can We Alter the Need for Blood Transfusion?

BACKGROUND: Children with neuromuscular complex chronic conditions (NMCCC) frequently undergo hip reconstruction surgery requiring blood transfusion. The purpose of this study is to examine the efficacy of tranexamic acid (TXA) to reduce blood loss and transfusion requirement in NMCCC children undergoing hip reconstruction surgery. METHODS: Children with NMCCC undergoing hip reconstruction surgery between 2013 and 2018 were identified. Two cohorts were identified: those who received TXA and those who did not. Patient and surgical characteristics between cohorts were used for propensity matching. Patients were matched on the basis of comorbid factors, bilateral involvement, pelvic osteotomy, open reduction, and surgeon. Comparative outcomes between cohorts were analyzed for intraoperative and postoperative blood loss and transfusion requirements and length of hospital stay (LOS). RESULTS: A total of 166 patients underwent hip surgery at an average of 9.6 years (SD, 4.0). Propensity matching utilized 72% of the cohort including 47 TXA and 72 non-TXA subjects. There were no differences in patient or surgical characteristics across matched groups. Fifteen (15/47, 32%) TXA subjects required a postoperative blood transfusion compared with the 47% (34/72) of non-TXA subjects who required a transfusion and intraoperative transfusion rates were similar between the 2 groups. There was no significant difference in complication rate (TXA, 79%; non-TXA, 86%), reported estimated blood loss (median=200 mLfor both) or LOS (median=6 d for both). Hematocrit levels were slightly higher in TXA subjects intraoperatively (P=0.047), at the end of surgery (P=0.04), and for the overall lowest perioperative level (P=0.04). The overall percent loss of estimated blood volume was less for those who were given TXA compared with those who were not (P=0.001). CONCLUSIONS: The use of TXA during hip reconstruction surgery in NMCCC children significantly reduced the percent loss of estimated blood volume and postoperative transfusion rate. Further prospective multicenter studies are needed to verify the positive effects and safety of TXA in the setting of hip reconstruction surgery in NMCCC children. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Occipital Plate Fixation in the Pediatric Population.

BACKGROUND: Occipital plate fixation has been shown to improve outcomes in cervical spine fusion. There is a paucity of literature describing occipital plate fixation, especially in the pediatric population. The authors reviewed a case series of 34 patients at a pediatric hospital who underwent cervical spine fusion with occipital plate fixation between 2003 and 2016. This study describes how occipital plates aid the cervical spine union in a case series of diverse, complex pediatric patients. METHODS: Our orthopaedic database at our institution was queried for patients undergoing an instrumented cervical spine procedure between 2003 and 2016. Medical records were used to collect diagnoses, fusion levels, surgical technique, and length of hospitalization, neurophysiological monitoring, complications, and revision procedures. RESULTS: Thirty-four patients met the inclusion criteria. The mean age was 10.9 years (range, 3-21 y). Indications for surgery included cervical instability, basilar invagination, and os odontoideum. These indications were often secondary to a variety of diagnoses, including trisomy 21, Klippel-Feil syndrome, and rheumatoid arthritis. The mean length of hospitalization was 10 days (range, 2 to 80 d). There were no cases of intraoperative dural leak, venous sinus bleeding from occipital screw placement, or implant-related complications. Postoperative complications included 2 cases of nonunion. Eight patients (24%) had follow-up surgery, only 3 (9%) of which were instrumentation revisions. Both patients with nonunion had repeat occipitocervical fixation procedures and achieved union with revision. CONCLUSIONS: Occipital plate fixation was successful for pediatric cervical spine fusion in this diverse cohort. The only procedure-related complication demonstrated was delayed union or nonunion and implant loosening (4/34, 12%) and there were no plate-related complications. This novel case series shows that occipital plate fixation is safe and effective for pediatric patients with complex diagnoses. LEVEL OF EVIDENCE: Level IV-case series.