Elicitation of broadly protective sarbecovirus immunity by receptor-binding domain nanoparticle vaccines.

Understanding vaccine-elicited protection against SARS-CoV-2 variants and other sarbecoviruses is key for guiding public health policies. We show that a clinical stage multivalent SARS-CoV-2 spike receptor-binding domain nanoparticle (RBD-NP) vaccine protects mice from SARS-CoV-2 challenge after a single immunization, indicating a potential dose-sparing strategy. We benchmarked serum neutralizing activity elicited by RBD-NPs in non-human primates against a lead prefusion-stabilized SARS-CoV-2 spike (HexaPro) using a panel of circulating mutants. Polyclonal antibodies elicited by both vaccines are similarly resilient to many RBD residue substitutions tested, although mutations at and surrounding position 484 have negative consequences for neutralization. Mosaic and cocktail nanoparticle immunogens displaying multiple sarbecovirus RBDs elicit broad neutralizing activity in mice and protect mice against SARS-CoV challenge even in the absence of SARS-CoV RBD in the vaccine. This study provides proof of principle that multivalent sarbecovirus RBD-NPs induce heterotypic protection and motivates advancing such broadly protective sarbecovirus vaccines to the clinic.

Adjuvanting a subunit COVID-19 vaccine to induce protective immunity.

The development of a portfolio of COVID-19 vaccines to vaccinate the global population remains an urgent public health imperative1. Here we demonstrate the capacity of a subunit vaccine, comprising the SARS-CoV-2 spike protein receptor-binding domain displayed on an I53-50 protein nanoparticle scaffold (hereafter designated RBD-NP), to stimulate robust and durable neutralizing-antibody responses and protection against SARS-CoV-2 in rhesus macaques. We evaluated five adjuvants including Essai O/W 1849101, a squalene-in-water emulsion; AS03, an α-tocopherol-containing oil-in-water emulsion; AS37, a Toll-like receptor 7 (TLR7) agonist adsorbed to alum; CpG1018-alum, a TLR9 agonist formulated in alum; and alum. RBD-NP immunization with AS03, CpG1018-alum, AS37 or alum induced substantial neutralizing-antibody and CD4 T cell responses, and conferred protection against SARS-CoV-2 infection in the pharynges, nares and bronchoalveolar lavage. The neutralizing-antibody response to live virus was maintained up to 180 days after vaccination with RBD-NP in AS03 (RBD-NP-AS03), and correlated with protection from infection. RBD-NP immunization cross-neutralized the B.1.1.7 SARS-CoV-2 variant efficiently but showed a reduced response against the B.1.351 variant. RBD-NP-AS03 produced a 4.5-fold reduction in neutralization of B.1.351 whereas the group immunized with RBD-NP-AS37 produced a 16-fold reduction in neutralization of B.1.351, suggesting differences in the breadth of the neutralizing-antibody response induced by these adjuvants. Furthermore, RBD-NP-AS03 was as immunogenic as a prefusion-stabilized spike immunogen (HexaPro) with AS03 adjuvant. These data highlight the efficacy of the adjuvanted RBD-NP vaccine in promoting protective immunity against SARS-CoV-2 and have led to phase I/II clinical trials of this vaccine (NCT04742738 and NCT04750343).

SHIV-C109p5 NHP induces rapid disease progression in elderly macaques with extensive GI viral replication.

CCR5-tropic simian/human immunodeficiency viruses (SHIV) with clade C transmitted/founder envelopes represent a critical tool for the investigation of HIV experimental vaccines and microbicides in nonhuman primates, although many such isolates lead to spontaneous viral control post infection. Here, we generated a high-titer stock of pathogenic SHIV-C109p5 by serial passage in two rhesus macaques (RM) and tested its virulence in aged monkeys. The co-receptor usage was confirmed before infecting five geriatric rhesus macaques (four female and one male). Plasma viral loads were monitored by reverse transcriptase-quantitative PCR (RT-qPCR), cytokines by multiplex analysis, and biomarkers of gastrointestinal damage by enzyme-linked immunosorbent assay. Antibodies and cell-mediated responses were also measured. Viral dissemination into tissues was determined by RNAscope. Intravenous SHIV-C109p5 infection of aged RMs leads to high plasma viremia and rapid disease progression; rapid decrease in CD4+ T cells, CD4+CD8+ T cells, and plasmacytoid dendritic cells; and wasting necessitating euthanasia between 3 and 12 weeks post infection. Virus-specific cellular immune responses were detected only in the two monkeys that survived 4 weeks post infection. These were Gag-specific TNFα+CD8+, MIP1ß+CD4+, Env-specific IFN-γ+CD4+, and CD107a+ T cell responses. Four out of five monkeys had elevated intestinal fatty acid binding protein levels at the viral peak, while regenerating islet-derived protein 3α showed marked increases at later time points in the three animals surviving the longest, suggesting gut antimicrobial peptide production in response to microbial translocation post infection. Plasma levels of monocyte chemoattractant protein-1, interleukin-15, and interleukin-12/23 were also elevated. Viral replication in gut and secondary lymphoid tissues was extensive.IMPORTANCESimian/human immunodeficiency viruses (SHIV) are important reagents to study prevention of virus acquisition in nonhuman primate models of HIV infection, especially those representing transmitted/founder (T/F) viruses. However, many R5-tropic SHIV have limited fitness in vivo leading to many monkeys spontaneously controlling the virus post acute infection. Here, we report the generation of a pathogenic SHIV clade C T/F stock by in vivo passage leading to sustained viral load set points, a necessity to study pathogenicity. Unexpectedly, administration of this SHIV to elderly rhesus macaques led to extensive viral replication and fast disease progression, despite maintenance of a strict R5 tropism. Such age-dependent rapid disease progression had previously been reported for simian immunodeficiency virus but not for R5-tropic SHIV infections.

Socioeconomic, Racial, and Insurance Disparities in Clinical Outcomes After Surgery Among Patients With Idiopathic Scoliosis.

BACKGROUND: Socioeconomic status (SES), race, and insurance type correlate with initial curve severity for patients with idiopathic scoliosis, but less is known regarding how these variables impact surgical outcomes. The objectives of this study were to determine the influence of SES, race, and insurance on preoperative appointment attendance, likelihood of obtaining a preoperative second opinion, brace prescription, missed 6 or 12-month postsurgical appointments, incidence of emergency department visits 0 to 90 days after surgery, and major complications within a year of surgery. METHODS: A review of 421 patients diagnosed with idiopathic scoliosis who underwent surgery at a single high-volume pediatric spinal deformity institution between May 2015 and October 2021 was conducted. Area Deprivation Index, a quantitative measure of SES, was collected. Scores were stratified by quartile; higher scores indicated a lower SES. χ 2 tests for correlation were performed to determine whether clinical outcomes were dependent upon Area Deprivation Index, race, or insurance type; P ≤0.05 was significant. RESULTS: The sample was 313 Caucasian (74%), 69 (16%) black, and 39 (9.3%) other patients. More patients had private versus public insurance (80% vs 20%) and were of higher SES. The likelihood of missing preoperative appointments was higher for black patients ( P = 0.037). Those with lower SES missed more postoperative appointments and received less bracing and second opinions ( P = 0.038, P = 0.017, P = 0.008, respectively). Being black and publicly insured correlated with fewer brace prescriptions ( P < 0.001, P = 0.050) and decreased rates of obtaining second opinions ( P = 0.004,  P = 0.001). CONCLUSION: Patients with idiopathic scoliosis surgery who were Caucasian, privately insured, and of higher SES were more likely to seek preoperative second opinions, be prescribed a brace, and attend postoperative appointments. Recognition of the inherent health care disparities prevalent within each pediatric spine surgery referral region is imperative to better inform local and national institutional level programs to educate and assist patients and families most at risk for disparate access to scoliosis care. LEVEL OF EVIDENCE: Level III; retrospective case-control study.

Do Pedicle Screws That Terminate in the Costovertebral Joint Compromise Proximal Anchor Fixation in a Dual Growing Rod Construct?

INTRODUCTION: Growing rods (GRs) are used to treat early-onset scoliosis (EOS) recalcitrant to bracing and casting. Proximal anchor pullout, a known complication of GR constructs, can result in spinal cord injury if pedicle screw anchors are placed with a lateral-to-medial trajectory. To mitigate this risk, a more straightforward and potentially safer trajectory may result in screws that terminate within the costovertebral joint (CVJ). We asked, how often does CVJ placement occur and does this technique increase the rate of failure in GR constructs? METHODS: We retrospectively reviewed 35 patients with EOS treated with dual GR with >2-year follow-up excluding patients with skeletal dysplasia or history of previous posterior instrumentation. Patient demographics, radiographic parameters, and implant constructs were assessed. RESULTS: Of patients meeting the inclusion criteria, 18/35 (51%) were females with an average age of 7.96 (range: 4.0 to 15.2) years at surgery with a follow-up of 3.7 (range: 2.0 to 7.7) years. Five (14%) patients had idiopathic EOS, 5 (14%) had congenital EOS, 12 (34%) had neuromuscular EOS, 10 (29%) had syndromic scoliosis, and 3 (9%) had another etiology for EOS. Among 195 proximal pedicle screws placed, 19 (10%) terminated within the CVJ, and 13 patients (37%) had at least 1 CVJ screw. Two patients (6%) experienced unilateral proximal pullout. In both patients, the anchors on the affected side included 1 of 2 screws within the CVJ. Both patients had constructs that included 2 screws on the side that pulled out and 3 screws on the side that did not. None of the remaining 17 CVJ screws led to implant failure. CONCLUSION: Pedicle screw placement within the CVJ is common and does not appear to significantly contribute to proximal screw pullout; however, it may contribute to unilateral implant failure in constructs employing only 2 proximal screws, where 1 of those 2 screws terminates within the CVJ. Construct modifications should be considered in this scenario. LEVEL OF EVIDENCE: Level III.

PET/CT targeted tissue sampling reveals virus specific dIgA can alter the distribution and localization of HIV after rectal exposure.

Human immunodeficiency virus (HIV) vaccines have not been successful in clinical trials. Dimeric IgA (dIgA) in the form of secretory IgA is the most abundant antibody class in mucosal tissues, making dIgA a prime candidate for potential HIV vaccines. We coupled Positron Emission Tomography (PET) imaging and fluorescent microscopy of 64Cu-labeled, photoactivatable-GFP HIV (PA-GFP-BaL) and fluorescently labeled dIgA to determine how dIgA antibodies influence virus interaction with mucosal barriers and viral penetration in colorectal tissue. Our results show that HIV virions rapidly disseminate throughout the colon two hours after exposure. The presence of dIgA resulted in an increase in virions and penetration depth in the transverse colon. Moreover, virions were found in the mesenteric lymph nodes two hours after viral exposure, and the presence of dIgA led to an increase in virions in mesenteric lymph nodes. Taken together, these technologies enable in vivo and in situ visualization of antibody-virus interactions and detailed investigations of early events in HIV infection.

Localization of infection in neonatal rhesus macaques after oral viral challenge.

Vertical transmission of human immunodeficiency virus (HIV) can occur in utero, during delivery, and through breastfeeding. We utilized Positron Emission Tomography (PET) imaging coupled with fluorescent microscopy of 64Cu-labeled photoactivatable-GFP-HIV (PA-GFP-BaL) to determine how HIV virions distribute and localize in neonatal rhesus macaques two and four hours after oral viral challenge. Our results show that by four hours after oral viral exposure, HIV virions localize to and penetrate the rectal mucosa. We also used a dual viral challenge with a non-replicative viral vector and a replication competent SHIV-1157ipd3N4 to examine viral transduction and dissemination at 96 hours. Our data show that while SHIV-1157ipd3N4 infection can be found in the oral cavity and upper gastrointestinal (GI) tract, the small and large intestine contained the largest number of infected cells. Moreover, we found that T cells were the biggest population of infected immune cells. Thus, thanks to these novel technologies, we are able to visualize and delineate of viral distribution and infection throughout the entire neonatal GI tract during acute viral infection.

Mortality after spinal fusion in children with cerebral palsy and cerebral-palsy-like conditions: A 30-year follow-up study.

AIM: To report survival probability of a large cohort of children with cerebral palsy (CP) after spinal fusion. METHOD: All children with CP who had spinal fusion between 1988 and 2018 at the reporting facility were reviewed for survival. Death records of the institutional CP database, institutional electronic medical records, publicly available obituaries, and the National Death Index through the US Centers for Disease Control were searched. Survival probabilities with different surgical eras, comorbidities, ages, and curve severities were compared using Kaplan-Meier curves. RESULTS: A total of 787 children (402 females, 385 males) had spinal fusion at a mean age of 14 years 1 month (standard deviation 3 years 2 months). The 30-year estimated survival was approximately 30%. Survival decreased for children who had spinal fusion at younger ages, longer postoperative hospital stays, longer postoperative intensive care unit stays, gastrostomy tubes, and pulmonary comorbidities. INTERPRETATION: Children with CP who required spinal fusions had reduced long-term survival compared with an age-matched typically developing cohort; however, a substantial number survived 20 to 30 years after the surgery. This study had no comparison group of children with CP scoliosis; therefore, we do not know whether correction of scoliosis affected their survival.

Does intrathecal baclofen therapy decrease the progression of hip displacement in young patients with cerebral palsy?

AIM: To evaluate the effects of intrathecal baclofen pump (ITBP) therapy on hip dysplasia in young patients with cerebral palsy (CP). METHOD: This was a retrospective cohort series of prospectively collected data. Inclusion criteria were all patients with CP in Gross Motor Function Classification System (GMFCS) levels IV or V who underwent ITBP placement under 8 years old with at least 5 years of follow-up. Thirty-four patients were matched to a control group of 71 patients based on GMFCS level, motor type, medical comorbidities, worst hip migration percentage at ITBP placement, age, and Modified Ashworth scale scores. Patients were followed for at least 5 years or until they had hip reconstructive surgery. The primary outcome was the development of hip displacement as measured by the migration percentage at the latest follow-up or the preoperative migration percentage before hip reconstruction. RESULTS: The migration percentage at last follow-up was not statistically different between groups (ITBP: 36.2%, non-ITBP: 44.4%, p = 0.14). The rates of future preventative, reconstructive, and recurrent hip surgery were not different between groups. INTERPRETATION: The use of ITBP as an early treatment of spasticity did not alter the natural history of progressive hip displacement in non-ambulatory patients with CP and hip displacement is likely multifactorial, not solely due to spasticity.

Minimally Displaced Lateral Humeral Condyle Fractures: Optimizing Follow-up and Minimizing Cost.

BACKGROUND: Minimally displaced fractures of the lateral humeral condyle (LHC) may be treated nonoperatively in a long arm cast, but there is not a standardized evidence-based protocol. The aim of this study was to evaluate our nonoperatively treated LHC fractures, determine the risk of subsequent displacement, analyze our practice variability, and develop an evidence-based protocol to safely manage children with LHC fractures and to evaluate potential savings related to this analysis. METHODS: We retrospectively reviewed clinical and radiographic parameters of all patients with LHC fractures at our institution from 2009 to 2015. All patients treated nonoperatively initially were included. We recorded demographic data and calculated the number of visits, casts applied, and radiographs within the first 4 weeks. We also analyzed practice variation among 27 treating providers. The number of children with subsequent displacement needing operative fixation was determined. We also looked at the average duration for each follow-up visit and the charges/costs associated with casting and radiographs. RESULTS: There were 271 children with LHC fractures treated nonoperatively. Twenty-one were excluded because of the lack of adequate radiographs. There were 157 boys and 93 girls (average age 6.7 y). According to the Jakob classification, fracture types were as follows: 1 (230), 2 (20), and 3 (0). Within the first 4 weeks, the average number of visits was 2.6 (range: 1 to 5), average number of casts was 2.4 (range: 1 to 4), and the average number of radiographs was 9.4 (range: 2 to 31). Only 3 patients with LHC fracture type Jakob 1 were taken to the operating room post injury (9, 12, and 15 d, respectively) for subsequent displacement. CONCLUSION: Displacement in appropriately selected LHC fractures treated nonoperatively was rare (3/250, 1.2%) in this cohort, and the data question the need for multiple visits and radiographs in the first 4 weeks. Optimal follow-up (proposed follow-up at 10 to 15 d after injury and then 4 to 6 wk with radiographs, including an internal oblique view) would be safe, minimize waste, and result in better value-based care. LEVEL OF EVIDENCE: Level IV.

Femoral Head Deformity Associated With Hip Displacement in Nonambulatory Cerebral Palsy: Results at Skeletal Maturity.

BACKGROUND: Maintaining femoral head shape (FHS) and acetabular sphericity are important goals in preventing long-term osteoarthritis in hips in children with cerebral palsy (CP). As acetabular morphology has been widely studied, our objective was to determine FHS in CP after triradiate cartilage (TRC) closure, a proxy for skeletal maturity, and the risk factors associated with residual deformity and osteoarthritis. METHODS: In this retrospective cohort study, patients with CP [Gross Motor Function Classification System (GMFCS) IV to V], minimum 4 yearly hip radiographs after age 10 years, and at least 1 radiograph after age 16 years, were included. Primary outcome was FHS (Rutz), stratified as "less severe" (Rutz A to B) and "more severe" (Rutz C to D). Secondary outcomes included migration percentage (MP), age at TRC closure, previous reconstructive (femoral with/without pelvic osteotomies) surgery, previous intrathecal baclofen, Tönnis osteoarthritis grade, and GMFCS level. Statistical analyses included χ 2 analysis and multiple logistic regression. RESULTS: One hundred sixty-three patients (326 hips) met the inclusion criteria, with TRC closure at age 14.0 (SD: 1.8) years. At final follow-up of 4.4 (SD: 2.4) years after TRC closure, 17% (55 hips), had a "more severe" FHS. From TRC closure to final follow-up, the frequencies of "less severe" hips decreased (-10%, P <0.001), while "more severe" increased (+115%, P <0.001). In multiple regression analysis, MP at TRC closure was the only significant risk factor associated with a "more severe" FHS at final follow-up ( P =0.03). Receiver operating characteristic curve analysis determined MP≥30.5% to be associated with a "more severe" FHS at final follow-up ( P <0.009). The FHS was not affected by reconstructive surgery, sex, GMFCS level, or intrathecal baclofen use. "Less severe" hips had lower Tönnis grades (0 to 1) compared with "more severe" hips (Tönnis grades 2 to 3) at final follow-up ( P <0.001). CONCLUSIONS: FHS at skeletal maturity was not influenced by prior reconstructive surgery but was negatively affected when MP≥30.5% at the time of TRC closure. The extent of residual femoral head deformity correlated with the severity of osteoarthritis at final follow-up. LEVEL OF EVIDENCE: Level III.

Hip Displacement Does Not Change After Pelvic Obliquity Correction During Spinal Fusion in Children With Cerebral Palsy.

BACKGROUND: Children with cerebral palsy (CP) frequently develop both neuromuscular hip dysplasia and scoliosis, and occasionally, the timing of the worsening of both of these pathologies is concurrent. The question as to whether the hip or spine should be addressed first in CP remains controversial, with the majority of evidence being "expert opinion." The purpose of this project was to determine the impact of posterior spinal fusion (PSF) on the change in hip displacement for children with CP without previous reconstructive hip surgery. METHODS: This was an Institutional Review Board-approved study that observed 67 patients from 2004 to 2018. Inclusion criteria included children with CP, 18 years of age and younger, Gross Motor Function Classification System IV and V, undergoing PSF at a single tertiary care children's hospital with a minimum 2-year follow-up. The primary outcome was the change in hip displacement as quantified by the migration percentage (MP). The hip with the highest MP (worst hip) at the spine preoperative analysis were included for analysis. Triradiate cartilage (TRC) status and pelvic obliquity correction were analyzed with multivariate analysis. RESULTS: Sixty-seven patients were included for analysis, with a mean age of 12.5±2.3 years. The mean major curve angle of the major curve was 77±23 degrees and the mean preoperative pelvic obliquity was 21±12 degrees. There was no statistically significant change in MP after PSF from a mean preoperative value of 41±27%, to a mean postoperative value of 41±29% at the last follow-up, (P=0.76) The mean follow-up time was 4.1±2.7 years. TRC status (P=0.52) and the severity of pelvic obliquity (P=0.10) did not statistically impact the change in MP after PSF. CONCLUSION: PSF did not influence-either negatively or positively-the progression of hip displacement in children with CP, regardless of pelvic obliquity correction or TRC status. The lack of deterioration in hip displacement post-PSF, however, may suggest a protective effect of spine surgery. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

The Fate of the Bent Rod in Children With Osteogenesis Imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a genetic disorder characterized by brittle bones and long bone deformity. Realignment and intramedullary rodding with telescopic rods are indicated for progressive deformity and can help prevent fractures. Rod bending is a reported complication of telescopic rods and a common indication for revision; however, the fate of bent lower extremity telescopic rods in the setting of OI has not been reported. METHODS: Patients with OI at a single institution who underwent lower extremity telescopic rod placement with at least 1-year follow-up were identified. Bent rods were identified, and for these bone segments, we collected the location and angle of bend, subsequent telescoping, refracture, increasing angulation of bend, and date of revision. RESULTS: One hundred sixty-eight telescopic rods in 43 patients were identified. Forty-six rods (27.4%) bent during follow-up, with an average angulation of 7.3 (range: 1 to 24) degrees. In patients with severe OI, 15.7% of rods bent compared with 35.7% in nonsevere OI ( P =0.003). The proportion of bent rods was different between independent and nonindependent ambulators (34.1% and 20.5%; P =0.035). Twenty-seven bent rods (58.7%) were revised, with 12 rods (26.0%) revised early (within 90 d). The angulation of rods that were revised early was significantly higher than rods not (14.6 and 4.3 degrees, P <0.001). Of the 34 bent rods not revised early, the average time to revision or final follow-up was 29.1 months. Twenty-five rods (73.5%) continued to telescope, 14 (41.2%) increased in angulation (average 3.2 degrees), and 10 bones (29.4%) refractured. None of the refractures required immediate rod revision. Two bones had multiple refractures. CONCLUSIONS: Bending is a common complication of telescopic rods in the lower extremities of patients with OI. It is more common in independent ambulators and patients with nonsevere OI, possibly because of the increased demand placed on the rods. Rods with a small bend and maintained fixation can telescope and need not be an indication for immediate revision. LEVEL OF EVIDENCE: Level III-Retrospective review.

Recurrent hip instability after hip reconstruction in cerebral palsy children with spastic hip disease.

BACKGROUND: Migration percentage (MP) is widely used to evaluate hip stability in children with spastic cerebral palsy (CP). Orthopedic surgeons need more objective information to make a proper hip reconstruction surgical plan and predict the outcome. METHODS: Medical records and plain radiographs of children with CP who underwent the hip reconstruction procedure for dysplasia were reviewed retrospectively. RESULTS: In total, 253 operated hips (140 patients; 11.7 ± 3.3 years old) were included in this study. MP at pre-operative (Tpre) was 35.3 ± 22.5%; at immediate follow-up (Tpost) was 5.9 ± 9.5%; at last follow-up (Tfinal) was 9.8 ± 10.8% (4.5 ± 2.3 years post-operative at age 16.3 ± 2.8 years). In hips with Melbourne Cerebral Palsy Hip Classification Scale (MCPHCS) grade 3 (n = 78), around 30-45% had an unsatisfactory outcome at Tpost and Tfinal. However, hips categorized as other grades showed only 2.1-9.1% of unsatisfactory outcome. In less affected hips (pre-operative MP<30%, n = 122), 109 hips (89.3%) had varus derotation osteotomy only, the other 13 hips (10.7%) were combined with a pelvic osteotomy. In more severely affected hips (pre-operative MP ≥ 30%, n = 131), 26 hips (19.8%) had varus derotation osteotomy only, the other 105 hips (80.2%) were combined with a pelvic osteotomy. CONCLUSIONS: Hips with pre-operative MP between 15 and 29% (MCPHCS grades 3) can be a higher risk group of recurrent hip instability after hip reconstruction surgery. Multiple indications beyond MP should be considered when indicating pelvic osteotomy or hip muscle release as combined procedures with varus femoral osteotomy for hip reconstruction in this milder group to achieve a consistent long-term satisfactory outcome.

A Sonography-based Decision Model for Use in Treatment of Developmental Dysplasia of the Hip.

The objective of this study was to delineate a model for management of developmental dysplasia of the hip (DDH) treatment that incorporates hip ultrasound with objective/predicative parameters at key decision-making times. Hip sonograms of 74 infants (59 females, 15 males; 141 hips) with DDH were retrospectively reviewed. Hip sonographic score (HSS; ranges 0-10) was developed to reflect hip status based on sonographic position, stability, and morphology. Analysis on different management groups (i.e., no treatment, successful treatment, and failed treatment) showed that the trend of HSS is helpful in predicting course of the disease and determining effectiveness of treatment. A model for the management of DDH that utilizes an HSS and frequency schedule for hip sonography that is aligned with times of critical treatment decisions is proposed. This model illustrates how hip sonography can bring added value when timed to guide critical treatment decisions. (Journal of Surgical Orthopaedic Advances 32(1):047-054, 2023).

Incidence of Deep Vein Thrombosis in Cerebral Palsy Following an Orthopaedic Surgical Event.

PURPOSE: The purpose of this study was to identify the incidence of venous thromboembolism (VTE) and characterize the demographics, comorbidities, and risk factors for patients with cerebral palsy (CP) having orthopaedic surgery. METHODS: All patients diagnosed with CP who underwent an orthopaedic surgical procedure at one institution between 2008 and 2017 were identified. Diagnosis codes and associated patient events were recovered from the electronic medical record. Each VTE event was reviewed to ascertain an actual VTE episode related to a surgical event. RESULTS: The review included 2583 orthopaedic surgical events in 1371 patients. Of the initial 88 cases identified, 28 cases had a deep thrombosis documented. Six cases of VTE occurred within 3 months following the surgical event. Three of these cases had thigh thrombosis, and 2 patients had upper arm thrombosis, and 1 patient had a superior vena cava thrombosis. On further workup, 5 of these 6 patients were identified as having a congenital hypercoagulable condition. CONCLUSIONS: VTE is a relatively rare occurrence after orthopaedic surgery in pediatric patients with CP, but when it occurs, a full hematologic workup for a congenital hypercoagulable condition is indicated. Based on the low incidence of thigh thrombosis, routine pharmacological or intermittent mechanical calf compression is not recommended. A careful clinical and family history should be performed to identify patients with possible genetic hypercoagulable conditions who would merit prophylaxis. LEVEL OF EVIDENCE: Level IV.

Neuromonitoring for Proximal Fibular Osteochondroma Excision.

BACKGROUND: The peroneal nerve is at risk when excising tumors in the proximal fibula. The rate of nerve injuries during proximal fibular tumor resection varies from 3% to 20%. Our goal was to report our experience with resection of osteochondromas in the proximal fibula and describe the technique and utility of neuromonitoring during excision of proximal fibular osteochondromas (PFO). METHODS: Patients with a diagnosis of symptomatic PFO who had undergone excision at one institution from 1994 to 2018 were included. An institutional review board-approved retrospective review was performed. Intraoperative neuromonitoring was provided from 2006 on by a single group utilizing a multimodality protocol. RESULTS: This study contains 29 patients who had excision of osteochondromas in the proximal fibula. Of these 29 consecutively monitored patients, there were 34 involved extremities. Intraoperative neuromonitoring alerts occurred in 10/29 (34.5%) procedures, which included 3 electromyography (EMG) (30%), 2 motor-evoked potential (20%), 1 somatosensory-evoked potential (10%), and 4 alerts with a combination of EMG/motor-evoked potential/somatosensory-evoked potential changes (40%). The interventions that were taken resulted in resolution of the neuromonitoring changes in all procedures. Postoperatively, we noted 2 (6.9%) new mild sensory deficits, which resolved during follow up. There were 3 patients in whom pre-existing sensory-motor deficits improved but not completely after surgery, 1 motor weakness, and 2 with residual paresthesia. In those initially presenting with paresis, there was improvement in 8 of the 8 extremities by the last follow-up visit. Pain as a symptom was resolved in all cases. There were no iatrogenic foot drop injuries. The average follow up was 32.2 months. CONCLUSIONS: Neuromonitoring during PFO excision demonstrated a high number of alerts, all of which resolved following timely corrective action. The use of neuromonitoring may help decrease the risk of iatrogenic postoperative neurological deficits following fibular osteochondroma surgery. LEVEL OF EVIDENCE: Level IV.

Multicenter Series of Deformity Correction Using Guided Growth in the Setting of Osteogenesis Imperfecta.

BACKGROUND: The mainstay of deformity correction and fracture prevention for patients with osteogenesis imperfecta (OI) includes osteotomies and intramedullary rodding. Guided growth, described in the setting of skeletal dysplasias, offers a less invasive means of deformity correction. We report a multicenter case series of guided growth procedures in the setting of OI. METHODS: We retrospectively reviewed patients with OI at three institutions from April 2012 to April 2019: 18 patients underwent guided growth for angular deformity correction with minimum 1-year follow-up or full deformity correction and removal of guided growth hardware. Clinical characteristics, deformity measurements, and complications were collected. Distal femoral and proximal tibial hemiepiphysiodesis was performed using figure-of-eight plates and screws, and distal tibial medial hemiepiphysiodesis with cannulated screws. Preoperative and postoperative lateral distal femoral angle, medial proximal tibial angle, and lateral distal tibial angle were measured. Frequency and descriptive statistics were completed. RESULTS: Eighteen patients with OI (five-I, four-III, six-IV, three-V) underwent 33 guided growth procedures with mean follow-up of 3.09 years; all received routine bisphosphonate treatment. Preoperative and postoperative mean joint angles were measured. The location for hemiepiphysiodesis included 8 distal femoral medial, 2 distal femoral lateral, 8 proximal tibial medial, 3 proximal tibial lateral, and 12 distal tibial medial. Twelve of the 33 procedures were in patients who had an intramedullary rod; 1 demonstrated backout of the epiphyseal and metaphyseal screws of a distal femoral medial figure-of-eight plate. It was revised to a larger plate with longer screws and removed upon completion of deformity correction. CONCLUSION: Guided growth may be used as an effective means of angular deformity correction with dysplastic OI bone. Having an intramedullary rod did not preclude the use of a guided growth technique. One procedure demonstrated screw backout. Given the short stature associated with OI, performing a guided growth procedure at an early enough age to allow time for correction should be considered. LEVEL OF EVIDENCE: Level IV-case series.

Risk Factors for Rebound After Correction of Genu Valgum in Skeletal Dysplasia Patients Treated by Tension Band Plates.

BACKGROUND: Growth modulation using tension band plates (TBPs) is increasingly important for lower limb deformity correction in patients with skeletal dysplasia (SKD). Development of rebound deformity is a concern after TBP removal. Data regarding this complication are rare; therefore, we evaluated the prevalence and risk factors for rebound deformity in children with SKD undergoing correction of genu valgum using TBP. METHODS: All patients with SKD with genu valgum treated by TBP at the distal femur or/and proximal tibia at a single center were reviewed. Inclusion criteria were: (1) minimum 2-year follow-up after TBP removal or having revision surgery for rebound deformity and (2) implant removal age for girls 14 years and below and boys 16 years and below. Exclusion criteria were any femoral/tibial osteotomies during TBP treatment or follow-up. A change of ≥3 degrees of mechanical lateral distal femoral and/or medial proximal tibial angle was accepted as rebound deformity and analyzed statistically. RESULTS: Thirty-three patients (59 limbs; 52 femur and 29 tibia physes) met our criteria. Mean follow-up after implant removal was 43.7 months. Rebound deformities were seen in 43 limbs (39 femurs and 13 tibias). Boys had more rebound than girls; however, this was not influenced by body mass index. Femurs had more rebound than tibias. Patients in the rebound group were younger than the nonrebound group. Time from application to removal of TBP was shorter in the rebound versus nonrebound group. Overcorrected limbs had more rebound deformity than not overcorrected. The difference in growth velocity of lower limbs in the rebound versus nonrebound group was statistically significant. Patients with epiphyseal dysplasia had more rebound than metaphyseal dysplasia, but this was not statistically significant. CONCLUSION: Risk factors for developing a rebound deformity after correction of genu valgum using TBP in SKD included male sex, TBP surgery at a young age, short duration of TBP implantation, overcorrected extremity (mechanical axis deviation ≤1), and high percent growth velocity after TBP removal. LEVEL OF EVIDENCE: Level IV-retrospective study.

Applications and Error Ratios of Calibration Techniques in EOS, Orthoroentgenogram, and Teleoroentgenogram for Length Measurement: A Comparative Study.

BACKGROUND: Accurate length measurements of extremity bones are essential in treating limb deformities and length discrepancies in children. OBJECTIVE: This study aimed to determine errors in common techniques used to measure lower limb lengths in children. METHODS: Precision and instrument errors in length measurements were studied utilizing electro-optical system (EOS), orthoroentgenogram, and teleoroentgenogram The goal was to measure a 70-cm metallic rod phantom (average length of the lower extremity of a 10-year-old boy in the 50th percentile) in 3 phases. In Phase 1, the length measurements were performed in an EOS unit with internal calibrations, a magball/magstrip in various scan positions, and measurement with TraumaCAD software. In Phase 2, the measurements were repeated utilizing a single radiation "shot" teleoroentgenogram. In Phase 3, an orthoroentgenogram was utilized with a radiopaque ruler reference. The reliability and validity of measurements were calibrated by 4 physicians (a radiologist, senior orthopaedic attending, and 2 orthopaedic fellows). RESULTS: EOS measurements utilizing internal references had excellent accuracy (for a 700-mm real length, magnification error (ME)] of 0.09%. Teleoroentgenogram with a magball reference and measurements performed with automatic calibration by TraumaCAD program results in ME of 1.83% with insignificant intraobserver/interobserver difference. Teleoroentgenogram with a magball or magstrip reference measured manually showed that the magball has higher intraobserver/interobserver variance than magstrip, with a 6.60 and 0.33-mm SD, respectively. The length by manual measurement utilizing the magstrip has ME of 2.21%. Orthoroentgenogram is accurate with ME of 0.26%, but does not allow anatomical analysis and is also radiation-costly. CONCLUSION: EOS and orthoroentgenogram are very accurate for length measurements. Teleoroentgenogram is less accurate in measuring length; however, addition of an external reference (magball, magstrip) placed lateral to the target improves accuracy. Automatic calibration with computer-based analysis of the external reference improves the accuracy more than manual calibration. If manual calibration is utilized, the length measurement is less accurate with the magball than the magstrip. LEVEL OF EVIDENCE: Level II-comparative in vitro study.