Multiple Horizontal Mini-chromosome Transfers Drive Genome Evolution of Clonal Blast Fungus Lineages.

Crop disease pandemics are often driven by asexually reproducing clonal lineages of plant pathogens that reproduce asexually. How these clonal pathogens continuously adapt to their hosts despite harboring limited genetic variation, and in absence of sexual recombination remains elusive. Here, we reveal multiple instances of horizontal chromosome transfer within pandemic clonal lineages of the blast fungus Magnaporthe (Syn. Pyricularia) oryzae. We identified a horizontally transferred 1.2Mb accessory mini-chromosome which is remarkably conserved between M. oryzae isolates from both the rice blast fungus lineage and the lineage infecting Indian goosegrass (Eleusine indica), a wild grass that often grows in the proximity of cultivated cereal crops. Furthermore, we show that this mini-chromosome was horizontally acquired by clonal rice blast isolates through at least nine distinct transfer events over the past three centuries. These findings establish horizontal mini-chromosome transfer as a mechanism facilitating genetic exchange among different host-associated blast fungus lineages. We propose that blast fungus populations infecting wild grasses act as genetic reservoirs that drive genome evolution of pandemic clonal lineages that afflict cereal crops.

Post-traumatic cortical cystic lesions in children: three case reports and a systematic review of the literature.

Post-traumatic cortical cystic lesions are rare radiolucent lesions that appear as a complication of low-severity fractures in children. Their relevance lies in the fact that few cases of these lesions have been described to date, so they are little known among clinicians caring for children. Three case reports of well-circumscribed cortical lytic lesions detected at 2-4 months during the follow-up of non-displaced distal radius fractures in children aged 9, 7, and 2 years are presented. The consistent clinical history and typical radiological features allowed the accurate diagnosis of post-traumatic cortical cystic lesion, without the need for advanced imaging tests or biopsy. At 12-, 8- and 11-month follow-ups, respectively, the lesions either disappeared or decreased in size. This benign and self-limited lesion should be correctly recognized to avoid confusion with other diagnoses, advanced imaging tests or biopsies, and unnecessary parental concerns.

Synthetic suture tape for medial patellofemoral ligament reconstruction is an effective treatment for complex paediatric patellofemoral instability.

PURPOSE: To assess the outcomes of medial patellofemoral ligament (MPFL) reconstruction using synthetic suture tape in paediatric patients with patellofemoral instability (PFI). METHODS: This ambispective comparative study, conducted from 2014 to 2022, included paediatric patients who underwent MPFL reconstruction with synthetic suture tape and had a minimum follow-up of 1 year. Pre- and postoperative clinical and functional outcomes, patient satisfaction and complications were assessed. RESULTS: The study comprised 22 patients (29 knees), with a median age at surgery of 14.4 years (interquartile range [IQR] 10.9-16.7) and a median follow-up of 46.5 months (24.7-66). Notably, 13 knees (44.8%) had open growth plates at the time of surgery. The cohort included patients with Down syndrome (3 patients), Ehlers-Danlos (2), arthrogryposis (1), generalized joint hypermobility (8) and previous unsuccessful PFI surgeries (8). Concomitant procedures were performed on 16 knees. Postoperatively, improvements were observed in all but one patient, who reported residual pain. There were two other complications: one suture-tape rupture and one surgical wound infection. Functional scores significantly improved: Kujala, +14 points (7-29) (p < 0.001); IKDC, +10.5 points (5.2-25.3) (p < 0.001); Tegner, +2 points (0-4) (p < 0.001); Lysholm, +15 points (0-37.5) (p < 0.001). Most patients achieved excellent outcomes by Crosby-Insall criteria (21 patients, 72.4%) and reported high satisfaction (23 patients, 79.3%). CONCLUSIONS: MPFL reconstruction using synthetic suture tape is a viable and effective treatment for paediatric patients with PFI, particularly for those with connective tissue disorders, generalized joint hypermobility or past surgical failures, significantly enhancing clinical and functional outcomes with an acceptable complication rate. LEVEL OF EVIDENCE: Level IV.

Thioetherification of Br-Mercaptobiphenyl Molecules on Au(111).

Thioether polymers are fundamental for a variety of applications. Their synthesis is, however, more challenging than that of other metal-catalyzed reactions due to the reported detachment of the S atom during thermal activation. In this study, it has been demonstrated unambiguously that thermal annealing results in the thioetherification of the 4-bromo-4-mercaptobiphenyl molecule (Br-MBP) adsorbed on the surface of Au(111). Through complementary techniques, such as scanning tunneling microscopy, spectroscopy, and first-principle calculations, we have identified four reaction steps, involving sulfhydryl or bromine molecular functional groups and leading to the formation of intermolecular C-S bonds. To form the thioether polymer and to overcome the competitive formation of C-C bonds, two reaction steps, the dehalogenation, and dissociation of the S-Au bond, must occur simultaneously. We detail the electronic properties of the phenyl-sulfur bond and the polymer as a function of the ligand length. This result suggests a wider perspective of this chemical synthesis.

Coronene-Based 2D Networks by On-Surface Skeletal Rearrangement of Sumanene Precursors.

The design of novel low-dimensional carbon materials is at the forefront of modern chemistry. Recently, on-surface covalent synthesis has emerged as a powerful strategy to synthesize previously precluded compounds and polymers. Here, we report a scanning probe microscopy study, complemented by theoretical calculations, about the sequential skeletal rearrangement of sumanene-based precursors into a coronene-based organometallic network by stepwise intra- and inter-molecular reactions on Au(111). Interestingly, upon higher annealing, the formed organometallic networks evolve into two-dimensional coronene-based covalently-linked patches through intermolecular homocoupling reactions. A new reaction mechanism is proposed based on the role of C-Au-C motifs to promote two stepwise carbon-carbon couplings to form cyclobutadiene bridges. Our results pave avenues for the conversion of molecular precursors on surfaces, affording the design of unexplored two-dimensional organometallic and covalent materials.

On-Surface Synthesis of Non-Benzenoid Nanographenes Embedding Azulene and Stone-Wales Topologies.

The incorporation of non-benzenoid motifs in graphene nanostructures significantly impacts their properties, making them attractive for applications in carbon-based electronics. However, understanding how specific non-benzenoid structures influence their properties remains limited, and further investigations are needed to fully comprehend their implications. Here, we report an on-surface synthetic strategy toward fabricating non-benzenoid nanographenes containing different combinations of pentagonal and heptagonal rings. Their structure and electronic properties were investigated via scanning tunneling microscopy and spectroscopy, complemented by computational investigations. After thermal activation of the precursor P on the Au(111) surface, we detected two major nanographene products. Nanographene Aa-a embeds two azulene units formed through oxidative ring-closure of methyl substituents, while Aa-s contains one azulene unit and one Stone-Wales defect, formed by the combination of oxidative ring-closure and skeletal ring-rearrangement reactions. Aa-a exhibits an antiferromagnetic ground state with the highest magnetic exchange coupling reported up to date for a non-benzenoid containing nanographene, coexisting with side-products with closed shell configurations resulted from the combination of ring-closure and ring-rearragement reactions (Ba-a , Ba-s , Bs-a and Bs-s ). Our results provide insights into the single gold atom assisted synthesis of novel NGs containing non-benzenoid motifs and their tailored electronic/magnetic properties.

Is reduction necessary in overriding metaphyseal distal radius fractures in children under 11 years: a systematic review and meta-analysis of comparative studies.

OBJECTIVE: To determine the necessity of reduction in the treatment of overriding metaphyseal distal radius fractures (DRF) in children under 11 years. METHODS: In this systematic review and meta-analysis, PubMed, Embase, and Cochrane databases were searched to retrieve studies published from inception to 2023. Two reviewers independently screened for studies with observational or randomized control design comparing two treatments for overriding metaphyseal DRF in patients under 11 years: simple casting without reduction (SC group) versus closed reduction plus casting or pin fixation (CRC/F group); with varying outcomes reported (CRD471761). The risk of bias was assessed using the ROBINS-I tool. RESULTS: Out of 3,024 screened studies, three met the inclusion criteria, 180 children (mean age 7.1 ± 0.9 years) with overriding metaphyseal DRF: SC-group (n = 79) versus CRC/F-group (n = 101). Both treatment groups achieved 100% fracture consolidation without requiring further manipulation. The SC-group showed significantly fewer complications (mean difference [MD] 0.08; 95% CI [0.01, 0.53]; I2 = 22%; P < 0.009) and trends towards better sagittal alignment (MD 5.11; 95% CI [11.92, 1.71]; I2 = 94%; P < 0.14), less reinterventions (MD 0.31; 95% CI [0.01, 8.31]; P < 0.48), and fewer patients with motion limitation at the end of follow-up (MD 0.23; 95% CI [0.03,  1.98]; P < 0.18), although these findings were not statistically significant. CONCLUSIONS: Despite a limited number of studies comparing SC versus CRC/F in overriding DRF in children under 11 years, this study suggests that anatomical reduction is not necessary. Treating these fractures with SC, even when presenting with an overriding position, leads to reduced complications, shows a trend towards fewer reinterventions, improved sagittal alignment, and less limitation in patient motion. LEVEL OF EVIDENCE: Level III, Systematic review of Level-III studies.

Structural Expansion of Cyclohepta[def]fluorene towards Azulene-Embedded Non-Benzenoid Nanographenes.

Non-benzenoid non-alternant nanographenes (NGs) have attracted increasing attention on account of their distinct electronic and structural features in comparison to their isomeric benzenoid counterparts. In this work, we present a series of unprecedented azulene-embedded NGs on Au(111) during the attempted synthesis of cyclohepta[def]fluorene-based high-spin non-Kekulé structure. Comprehensive scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) evidence the structures and conformations of these unexpected products. The dynamics of the precursor bearing 9-(2,6-dimethylphenyl)anthracene and dihydro-dibenzo-cyclohepta[def]fluorene units and its reaction products on the surface are analyzed by density functional theory (DFT) and molecular dynamics (MD) simulations. Our study sheds light on the fundamental understanding of precursor design for the fabrication of π-extended non-benzenoid NGs on a metal surface.

Is There a Relationship Between the Functional Level of Juvenile and Adolescent Patients With Down Syndrome and Hip Dysplasia?

BACKGROUND: The prevalence of hip dysplasia among patients with Down syndrome (DS) is higher than in the general population. We hypothesize that a relationship may exist between functional level and hip dysplasia in DS, but this has not been studied to date. The aim of this study is to evaluate whether there is a relationship between functional level and radiographic parameters of hip dysplasia or other measures. METHODS: Retrospective cross-sectional comparative study of 652 patients with DS from a pediatric referral center database. Patients over 8 years of age with an anteroposterior pelvis radiograph and with no exclusion criteria were selected, totaling 132 patients (264 hips; 54.55% females; mean age 12.96 ± 2.87 y). Several radiographic parameters of the acetabulum [Sharp angle (SA), Tönnis angle (TA), Wiberg center-edge angle (W-CEA), extrusion index (EI), and acetabular retroversion signs], the proximal femur [neck shaft angle (NSA)], and joint congruence [Shenton line (SL)] were assessed. Patients were classified into 2 levels based on functional skills. A multivariate association analysis was performed between radiographic parameters and functional level. RESULTS: Sixty-one patients were compatible with a functional level I and 71 with a level II. Forty-six hips were dysplastic and 60 were borderline according to the W-CEA. A statistically significant relationship was found between the categorical distribution of certain radiographic measurements of hip dysplasia (EI, SA, TA, W-CEA, SL, and classification by functional level ( P < 0.0005). A significant receiver operating characteristic curve was obtained for W-CEA with a cutt-off point at 26.4 degrees for level I (area under the curve = 0.763; P < 0.005; sensitivity = 0.800 and specificity = 0.644). There was a fairly high correlation between EI and TA (0.749; P < 0.0005), EI and W-CEA (-0.817; P < 0.0005), and TA and W-CEA (-0.748; P < 0.0005). Numerous hips showed signs of acetabular retroversion, with no significant differences found between functional levels or association with hip dysplasia measures. CONCLUSIONS: The present study reveals a relationship between an increased risk of hip dysplasia and reduced functional levels in DS children older than 8 years. These findings may guide individualized clinical follow-up of hip development in DS children considering their functional level. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Long-term Impact of Planovalgus Foot on Activities of Daily Living in Patients With Down Syndrome.

INTRODUCTION: Planovalgus foot (PVF) is the most common orthopaedic abnormality in children with Down syndrome (DS), and as a result these patients rarely develop an adequate plantar arch in adulthood. The present study aims to evaluate the impact of PVF on activities of daily living and participation in sports among young adults with DS and determine whether this impact is related to the degree of foot deformity based on clinical and imaging studies. METHODS: Observational analytical study examining a database of 649 patients with DS from a pediatric referral center, identifying those individuals over age 20 years at the time of the study with a childhood diagnosis of PVF. Finally, 51 patients (102 feet) were evaluated based on clinical and imaging studies, and function was assessed using the The Foot and Ankle Outcome Score (FAOS) and the Visual Analogue Scale (VAS) pain scale. A correlation analysis was performed to determine the clinical and radiographic variables associated with functional outcomes. Linear regression models were obtained to quantify the impact of these variables on function. RESULTS: Patients had a mean age of 26.14±3.88 years and body mass index of 24.51±4.57. Clinically, 63.65% presented grade 3 or 4 PVF, and most were flexible. Radiographically, midfoot flattening was mild-moderate in 92.16%, 58.82% had medial talo-navicular uncoverage, and 30.39% had an increased hallux valgus (HV) angle. Mean scores for all FAOS subscales were between 65 and 71% and the mean VAS score was 1.45±1.96. An association analysis revealed a tendency toward lower scores on all FAOS subscales and greater pain according to the VAS scale in more severe PVF and in cases of moderate HV with asymmetry between feet. Linear regression models showed that major contributors to functional scores were radiographic evidence of hindfoot valgus, midfoot abduction, and flattening, and HV. CONCLUSIONS: Young adults with DS who are diagnosed with PVF in childhood have acceptable functional scores and low pain. Alteration of radiographic parameters toward flatter, more valgus and abducted feet and greater and asymmetric HV tend to be associated with worse long-term functional scores in activities of daily living and sports participation and increased pain. Therefore, non-operative management of these patients is justified, although individualized treatment is recommended. LEVEL OF EVIDENCE: Level IV, Case series.

Design and Manipulation of a Minimalistic Hydrocarbon Nanocar on Au(111).

Nanocars are carbon-based single-molecules with a precise design that facilitates their atomic-scale control on a surface. The rational design of these molecules is important in atomic and molecular-scale manipulation to advance the development of molecular machines, as well as for a better understanding of self-assembly, diffusion and desorption processes. Here, we introduce the molecular design and construction of a collection of minimalistic nanocars. They feature an anthracene chassis and four benzene derivatives as wheels. After sublimation and adsorption on an Au(111) surface, we show controlled and fast manipulation of the nanocars along the surface using the tip of a scanning tunneling microscope (STM). The mechanism behind the successful displacement is the induced dipole created over the nanocar by the STM tip. We utilized carbon monoxide functionalized tips both to avoid decomposition and accidentally picking the nanocars up during the manipulation. This strategy allowed thousands of maneuvers to successfully win the Nanocar Race II championship.

A Truncated Singleton NLR Causes Hybrid Necrosis in Arabidopsis thaliana.

Hybrid necrosis in plants arises from conflict between divergent alleles of immunity genes contributed by different parents, resulting in autoimmunity. We investigate a severe hybrid necrosis case in Arabidopsis thaliana, where the hybrid does not develop past the cotyledon stage and dies 3 weeks after sowing. Massive transcriptional changes take place in the hybrid, including the upregulation of most NLR (nucleotide-binding site leucine-rich repeat) disease-resistance genes. This is due to an incompatible interaction between the singleton TIR-NLR gene DANGEROUS MIX 10 (DM10), which was recently relocated from a larger NLR cluster, and an unlinked locus, DANGEROUS MIX 11 (DM11). There are multiple DM10 allelic variants in the global A. thaliana population, several of which have premature stop codons. One of these, which has a truncated LRR-PL (leucine-rich repeat [LRR]-post-LRR) region, corresponds to the DM10 risk allele. The DM10 locus and the adjacent genomic region in the risk allele carriers are highly differentiated from those in the nonrisk carriers in the global A. thaliana population, suggesting that this allele became geographically widespread only relatively recently. The DM11 risk allele is much rarer and found only in two accessions from southwestern Spain-a region from which the DM10 risk haplotype is absent-indicating that the ranges of DM10 and DM11 risk alleles may be nonoverlapping.

Long-term Outcomes of Talonavicular Arthrodesis for the Treatment of Planovalgus Foot in Children With Cerebral Palsy.

BACKGROUND: Planovalgus foot (PVF) in cerebral palsy (CP) tends toward progression and rigidity in adolescence, especially in patients with greater functional impairment. Deformity at the talonavicular joint justifies the use of talonavicular arthrodesis as a corrective surgical technique. This study aims to assess patient or caregiver functional satisfaction and radiographic outcomes of talonavicular arthrodesis for PVF in CP patients with assisted ambulation in the long-term. METHODS: Retrospective comparative study of level III and level IV pediatric CP patients who underwent talonavicular arthrodesis for PVF between 1999 and 2010 as part of multilevel surgery and with a minimum follow-up of 10 years. Radiologic correction at 10 years was compared with preintervention values, and functional impact at 10 years was measured by the foot function index (FFI); correlation between radiologic measurements and FFI were obtained, and complications were recorded. RESULTS: Forty-nine PVFs in 25 patients with CP (72% level III and 28% level IV) were included; 52% were male. The patients had a median age of 12 years at the time of surgery (range: 11 to 15) and 23 years at the time of the study (21 to 26). Significant (P<0.01) pre-post radiologic improvements were obtained in Meary angle (37.86±10.7/8.37±5.5 degrees), calcaneal pitch (3.20±8.1/13.22±5.6 degrees), lateral talocalcaneus angle (42.18±12.1/25.29±2.9 degrees), Moreau-Costa-Bartani angle (167.04±8/146.12±7.1 degrees), talus-first metatarsal angle (27.92±13.9/9.69±4.4 degrees), anteroposterior talocalcaneal angle (37.61±7.4/22.61±2.4 degrees), and talus coverage angle (37.04±11.11/2.45±2.5 degrees). At 10 years postoperatively, functional outcome measured with the FFI was satisfactory (33.9±15.2%) and the mean maximum pain was 3.04; 56% of cases had mild pain. All patients were able to wear an ankle-foot orthosis and 8 no longer needed the device. A significant correlation was found between the talofirst metatarsal angle and the FFI (P=0.024). There were 8% of cases with screw protrusion and 14% presented pseudarthrosis, most of them asymptomatic. CONCLUSIONS: The adequate functional outcome, as well as the persistence of long-term radiologic correction and acceptable number of complications, enables us to recommend talonavicular arthrodesis as an alternative treatment to consider in level III and level IV CP patients with PVF. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Anisotropic Electron Conductance Driven by Reaction Byproducts on a Porous Network of Dibromobenzothiadiazole on Cu(110).

Efficiency in charge-transport is a fundamental but demanding prerequisite to allow better exploitation of molecular functionalities in organic electronics and energy-conversion systems. Here, we report on a mechanism that enables a one-dimensional conductance structure by connecting discrete molecular states at 2.1 eV through the pores of a metal-organic network on Cu(110). Two adjacent, periodic and isoenergetic contributions, namely a molecular resonance and the confined surface-state, add-up leading to anisotropic structures, as channels, observable in real-space conductance images. The adsorption configurations of Br atoms, inorganic byproduct of the redox-reacted 4,7-dibromobenzo[c]-1,2,5-thiadiazole (2Br-BTD) molecules on the copper surface, drive the confinement of the Cu surface state within the pores and critically control the channel continuity. Small displacements of the Br atoms change the local surface potential misaligning the energy levels. This work visualizes the effect of order-disorder transitions caused by the movement of single atoms in the electronic properties of two-dimensional organic networks.

Hierarchy in the Halogen Activation During Surface-Promoted Ullmann Coupling.

Within the collection of surface-supported reactions currently accessible for the production of extended molecular nanostructures under ultra-high vacuum, Ullmann coupling has been the most successful in the controlled formation of covalent single C-C bonds. Particularly advanced control of this synthetic tool has been obtained by means of hierarchical reactivity, commonly achieved by the use of different halogen atoms that consequently display distinct activation temperatures. Here we report on the site-selective reactivity of certain carbon-halogen bonds. We use precursor molecules halogenated with bromine atoms at two non-equivalent carbon atoms and found that the Ullmann coupling occurs on Au(111) with a remarkable predilection for one of the positions. Experimental evidence is provided by means of scanning tunneling microscopy and core level photoemission spectroscopy, and a rationalized understanding of the observed preference is obtained from density functional theory calculations.

Cooperative Action for Molecular Debromination Reaction on Cu(110).

Copper is the paradigmatic catalyzer of the Ullmann cross-coupling reaction. Despite this, its role in the reaction is still under debate. Here, we shed light on the mechanistic steps of debromination, characterizing a prototypical molecule, namely 4,7-dibromobenzo[ c]-1,2,5-thiadiazole (2Br-BTD), deposited on a Cu(110) surface. By means of scanning probe techniques and first principle calculations, we demonstrate the oxidative addition of Cu atoms leading to a -C-Cu-Br metal-organic complex. The scission of the strongly bound bromine atoms requires the cooperative action of neighboring complexes resulting in the formation of Cu-coordinated BTD structures.

Factors associated with Allergic Rhinitis in Colombian subpopulations aged 1 to 17 and 18 to 59.

BACKGROUND: Several studies have shown variations in the prevalence of allergic rhinitis (AR) around the world, and different potential predisposing factors. More studies are needed on risk factors, specifically in developing countries. This study explored the association of several factors and AR among urban residents in six cities of Colombia. METHODOLOGY: A cross-sectional study and a nested case-control study were carried out between 2009 and 2010 involving two Colombian subpopulations: children/adolescents and adults. Cases were affirmative respondents to "In the past 12 months, have you (or your child) had a problem with sneezing or a running or blocked nose, when you (or your child) did not have a cold or the flu?" "Controls" were subjects who never had been diagnosed with asthma, AR or atopic eczema by a physician, and whom did not report any symptoms in the past twelve months. Weighted logistic regression was used to assess the association of different factors with case/control status. RESULTS: Factors associated with AR in children/adolescents were family history of AR, acetaminophen consumption and high socioeconomic status. Among adults, family history of asthma, AR and atopic eczema, and cetaminophen consumption were associated with AR. Consumption of cereals among children/adolescents and eating eggs among adults showed protective associations. CONCLUSIONS: Our findings suggest the presence of previously unknown cultural, environmental and family factors associated with the presence of AR in Colombia.

Clinical Characteristics of Ocular Mucous Membrane Pemphigoid: A Systematic Review and Meta-Analysis.

PURPOSE: To synthesize the evidence and generate a combined weighted measure on the frequency of ocular manifestations of mucous membrane pemphigoid (OMMP). METHODS: Systematic literature review and meta-analysis, searching PubMed, Embase, VHL, and Google Scholar. Articles reporting patients with mucous membrane pemphigoid and ocular involvement were included. At least, two reviewers independently and in parallel participated in all the following phases; preliminary screening, full-text review, risk of bias assessment by validated tools, and data extraction. Qualitative analysis and meta-analysis were conducted. This study was previously registered in PROSPERO (CRD42023451844). RESULTS: Thirty-five studies met the inclusion criteria, comprising 1,439 patients and 1,040 eyes summarized in qualitative analysis. Twenty-eight studies were included in the meta-analysis. Ages included ranged from 60.4 to 75 years. Women were reported with more frequency. The mean time for diagnosis was 55.1 months, usually with bilateral ocular disease in 90% (95% CI 78%; 96%). Trichiasis and entropion were the most frequent manifestations in up to 92%, followed by symblepharon and punctate keratitis. Ankyloblepharon, persistent epithelial defects, and visual impairment were less frequent complications. Direct immunofluorescence positivity in conjunctival biopsies was 54% (95% CI 43%; 64%). Extraocular involvement was highly frequent, being oral and skin involvement the most frequently reported. CONCLUSIONS: Our systematic review and meta-analysis evidenced that patients around 60 years of age are the most affected population with a female preponderance, usually with bilateral ocular involvement. Trichiasis and entropion were the most frequent findings; although visual impairment and persistent epithelial defects were less reported, they should not be overlooked in suspected OMMP.

Does patella lowering as part of multilevel surgery improve knee kinematics in children with cerebral palsy and crouch gait? A meta-analysis of comparative studies.

Purpose: To evaluate differences in knee kinematic outcomes of patellar-lowering surgery, specifically patellar tendon advancement or patellar tendon shortening, compared with no-patellar-lowering surgery in multilevel surgery for children with cerebral palsy and crouch gait. Methods: Four databases were searched to retrieve studies published from inception until 2023. Three reviewers independently screened for studies with observational or randomized control designs, comparing two groups of patients with cerebral palsy and crouch gait who underwent multilevel surgery (with patellar-lowering surgery versus no-patellar-lowering surgery), where various gait analysis outcomes were reported (CRD42023450692). The risk of bias was assessed with the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool. Results: Seven studies (249 patients and 368 limbs) met the eligibility criteria. Patients undergoing patellar-lowering surgery demonstrated statistically significant improvements in knee flexion at initial contact (mean difference = -6.39; 95% confidence interval = [-10.4, -2.75]; p = 0.0006; I2 = 84%), minimum knee flexion in stance (mean difference = -14.27; 95% confidence interval = [-18.31, -10.23]; p < 0.00001; I2 = 89%), and clinical knee flexion contracture (mean difference = -5.6; 95% confidence interval = [-9.59, -1.6]; p = 0.006; I2 = 95%), with a significant increase in anterior pelvic tilt (mean difference = 2.97; 95% confidence interval = [0.58, 5.36]; p = 0.01; I2 = 15%). However, improvements in gait deviation index and decrease in peak knee flexion in swing did not reach statistical significance. Subgroup analysis reduced heterogeneity and revealed (1) greater improvement using patellar tendon shortening versus patellar tendon advancement techniques; (2) lack of knee flexion contracture improvement in high-quality or longer-term studies; (3) longer-term improvement only in minimum knee flexion in stance, with a decrease in peak knee flexion in swing; and (4) an inability to assess the potential benefit of rectus femoris procedure and hamstring preservation. Conclusions: Overall, the combination of patellar-lowering surgery with multilevel surgery demonstrated superior improvements in stance-phase knee kinematics compared with multilevel surgery alone, despite an increase in anterior pelvic tilt and a longer-term knee flexion reduction during the swing phase. Level of evidence: Level III, Systematic review of level III studies.