Bridge Plating is an Effective Adjunct Treatment for Complex Elbow Instability.

BACKGROUND: Managing persistent elbow instability and chronic dislocations presents challenges despite traditional treatments. Supplementary methods like immobilization and various fixations, though common, can carry high complication rates. This study assesses the efficacy of bridge plating in treating complex elbow instability through a retrospective review of patients. Data on characteristics, treatment duration, range of motion, complications, and evaluation scores were analyzed, providing insights into outcomes complications associated with bridge plating. RESULTS: Eleven patients were reviewed at an average follow-up of 80 ± 68 weeks. postoperatively. The average age was 53±14 years and there were 5 females and 6 males. The average BMI was 38. Bridge plating was used for a spectrum of complex elbow injuries. The average time from injury to bridge plating in acute cases was 29±19 days and 344±381 days in chronic cases. The average duration of bridge plating was 121 ± 72 days. At the time of plate removal, mean intraoperative elbow motion was extension 58±12°, flexion 107±14°, supination 66±23° and pronation 60±26°. At the latest follow-up visit, average elbow motion was extension 37±22°, Flexion 127± 17°, supination 72±15° and pronation 63±18°. There were 6 complications (55%); heterotopic ossification, ulnar neuropathy, wound failure over the plate in a thin patient, an ulnar shaft peri-prosthetic fracture due to a seizure induced fall, and elbow subluxation despite bridge plate fixation. One patient sustained a fracture of a 3.5mm locking bridge plate. One patient required a contracture release for persistent stiffness. Four of these complications can be directly attributed to the use of the bridge plate (36%). At final follow-up, the average patient rated elbow evaluation score was 34, with 0 indicating no pain and disability. The average single assessment numeric evaluation score was 66% for the 8 patients who had this available, with 100% being the best possible attainable score. CONCLUSION: Bridge plating effectively maintains joint reduction in selected complex elbow instability cases. However, patients with bridge plates often require a second surgery for removal and experience high rates of general complications due to the complexity of their condition.

Complementing model species with model clades.

Model species continue to underpin groundbreaking plant science research. At the same time, the phylogenetic resolution of the land plant Tree of Life continues to improve. The intersection of these two research paths creates a unique opportunity to further extend the usefulness of model species across larger taxonomic groups. Here we promote the utility of the Arabidopsis thaliana model species, especially the ability to connect its genetic and functional resources, to species across the entire Brassicales order. We focus on the utility of using genomics and phylogenomics to bridge the evolution and diversification of several traits across the Brassicales to the resources in Arabidopsis, thereby extending scope from a model species by establishing a "model clade". These Brassicales-wide traits are discussed in the context of both the model species Arabidopsis thaliana and the family Brassicaceae. We promote the utility of such a "model clade" and make suggestions for building global networks to support future studies in the model order Brassicales.

The effect of lateral collateral ligament repair tension on elbow stability: An in vitro biomechanical study.

BACKGROUND: The aim of this study was to determine the optimal repair tension of the lateral collateral ligament of the elbow by performing simulated active flexion with the arm in the varus gravity loaded position using an in vitro elbow simulator. METHODS: Eight cadaveric specimens were mounted in the varus gravity loaded orientation onto an elbow motion simulator. Four states were studied (intact, lateral collateral ligament injured, and 15 N and 20 N lateral collateral ligament repairs) with the forearm in supination and pronation. An electromagnetic tracking system was used to measure joint kinematics during active elbow flexion. FINDINGS: There was no difference in ulnohumeral rotation between the intact state and the 15 N repair (P = .150 for pronation; P = 1.0 for supination) or the 20 N repair (P = 1.0 for pronation; P = .568 for supination). For varus-valgus angulation, the 20 N repair was not statistically different from the intact state (P = .059 in pronation; P = 1.0 in supination). INTERPRETATION: Repair of the lateral collateral ligament following injury can restore joint kinematics with the arm in the varus position. A repair tension of 20 N was successful in restoring joint stability for simulated active motion with the forearm in pronation and supination. This study shows that when the lateral collateral ligament is repaired with adequate tension, avoidance of the varus position may not be as crucial during early motion.

Indomethacin for heterotopic ossification prophylaxis following surgical treatment of elbow trauma: a randomized controlled trial.

BACKGROUND: Heterotopic ossification is a frequent complication following surgical treatment of elbow trauma. The use of indomethacin to prevent heterotopic ossification is reported in the literature; however, its effectiveness is controversial. The purpose of this randomized, double-blind, placebo-controlled study was to determine whether indomethacin is effective in reducing the incidence and severity of heterotopic ossification after surgical management of elbow trauma. METHODS: Between February 2013 and April 2018, 164 eligible patients were randomized to receive postoperative indomethacin or placebo medication. The primary outcome was the incidence of heterotopic ossification on elbow radiographs at 1-year follow-up. Secondary outcomes included the Patient Rated Elbow Evaluation score, Mayo Elbow Performance Index score, and Disabilities of the Arm, Shoulder and Hand score. Range of motion, complications, and nonunion rates were also obtained. RESULTS: At 1-year follow-up, there was no significant difference in the incidence of heterotopic ossification between the indomethacin group (49%) and the control group (55%) (relative risk, 0.89; P = .52). There were no significant differences in postoperative Patient Rated Elbow Evaluation, Mayo Elbow Performance Index, and Disabilities of the Arm, Shoulder and Hand scores or range of motion (P = .16). The complication rate was 17% in both the treatment and control groups (P > .99). There were no nonunions in either group. CONCLUSION: This Level I study demonstrated that indomethacin prophylaxis against heterotopic ossification in the setting of surgically treated elbow trauma was not significantly different from placebo.

Developing multifunctional crops by engineering Brassicaceae glucosinolate pathways.

Glucosinolates (GSLs), found mainly in species of the Brassicaceae family, are one of the most well-studied classes of secondary metabolites. Produced by the action of myrosinase on GSLs, GSL-derived hydrolysis products (GHPs) primarily defend against biotic stress in planta. They also significantly affect the quality of crop products, with a subset of GHPs contributing unique food flavors and multiple therapeutic benefits or causing disagreeable food odors and health risks. Here, we explore the potential of these bioactive functions, which could be exploited for future sustainable agriculture. We first summarize our accumulated understanding of GSL diversity and distribution across representative Brassicaceae species. We then systematically discuss and evaluate the potential of exploited and unutilized genes involved in GSL biosynthesis, transport, and hydrolysis as candidate GSL engineering targets. Benefiting from available information on GSL and GHP functions, we explore options for multifunctional Brassicaceae crop ideotypes to meet future demand for food diversification and sustainable crop production. An integrated roadmap is subsequently proposed to guide ideotype development, in which maximization of beneficial effects and minimization of detrimental effects of GHPs could be combined and associated with various end uses. Based on several use-case examples, we discuss advantages and limitations of available biotechnological approaches that may contribute to effective deployment and could provide novel insights for optimization of future GSL engineering.

Sinapis genomes provide insights into whole-genome triplication and divergence patterns within tribe Brassiceae.

Sinapis alba and Sinapis arvensis are mustard crops within the Brassiceae tribe of the Brassicaceae family, and represent an important genetic resource for crop improvement. We performed the de novo assembly of Brassica nigra, S. alba, and S. arvensis, and conducted comparative genomics to investigate the pattern of genomic evolution since an ancient whole-genome triplication event. Both Sinapis species retained evidence of the Brassiceae whole-genome triplication approximately 20.5 million years ago (Mya), with subgenome dominance observed in gene density, gene expression, and selective constraint. While S. alba diverged from the ancestor of Brassica and Raphanus at approximately 12.5 Mya, the divergence time of S. arvensis and B. nigra was approximately 6.5 Mya. S. arvensis and B. nigra had greater collinearity compared with their relationship to either Brassica rapa or Brassica oleracea. Two chromosomes of S. alba (Sal03 and Sal08) were completely collinear with two ancestral chromosomes proposed in the Ancestral Crucifer Karyotype (ACK) genomic block model, the first time this has been observed in the Brassiceae. These results are consistent with S. alba representing a relatively ancient lineage of the species evolved from the common ancestor of tribe Brassiceae, and suggest that the phylogeny of the Brassica and Sinapis genera requires some revision. Our study provides new insights into the genome evolution and phylogenetic relationships of Brassiceae and provides genomic information for genetic improvement of these plants.

Recovery Trajectories Following Complex Elbow Injuries and Radial Head Arthroplasty: A Longitudinal Study Over 8 Years.

PURPOSE: Radial head arthroplasty (RHA) is commonly performed to manage comminuted unreconstructible radial head fractures. Although the outcomes of RHA are often satisfactory, revisions are usually considered when pain intensity is higher than expected. Therefore, it is important to investigate the recovery trajectories of patients following RHA over an extended period and the characteristics that may lead to unfavorable outcomes. METHODS: The Patient-Rated Elbow Evaluation (PREE) was used to assess recovery in 94 patients at baseline (within 2-7 days after surgery); 3 and 6 months; and 1, 2, 3, 4, 5, and 8 years after RHA. Lower PREE values indicate lower pain and disability. Latent growth curve analysis was used to determine classes of recovery. The characteristics of the participants in the identified recovery trajectory classes were then compared. RESULTS: Two distinct recovery trajectories were identified: optimal and suboptimal recoveries. Most patients (84%) belonged to the optimal recovery class, which exhibited significantly lower baseline PREE scores, a consistent pattern of recovery, and a relatively high rate of change. Patients in the suboptimal recovery class (16%) had significantly higher baseline PREE scores and continued to experience relatively higher levels of pain and disability for the duration of the study; their rate of recovery was much slower. Patients belonging to the 2 recovery trajectories did not differ based on age or sex. Although we had low power in other variables, a qualitative exploration showed that the number of current or previous smokers was higher in the suboptimal recovery trajectory class. CONCLUSIONS: In this longitudinal cohort study, we show that high postsurgical pain and disability, and potentially smoking, may adversely affect the recovery trajectory following RHA. Clinicians are recommended to assess these potential factors while considering revision surgeries. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Morphology of Proximal Ulna Bare Area: A Guide for Olecranon Osteotomy.

PURPOSE: Olecranon osteotomy is commonly used to obtain access to the distal humerus for fracture fixation. The goal of this study was to accurately describe the anatomy of the bare area to minimize articular cartilage damage while performing olecranon osteotomies. METHODS: Twenty cadaveric ulnae were denuded to expose the bare area. Laser surface mapping was used to create 3-dimensional models, and the nonarticular portions of the ulnae were digitally measured. RESULTS: The morphology of the bare area from all aspects of the proximal ulna was defined. The central bare area was consistent in its location, 4.9 ± 1.5 mm distal to the deepest portion of the trochlear notch and 23.2 ± 2.3 mm distal to the olecranon tip. The maximum chevron osteotomy apical angle to stay within the bare area averaged 110° ± 11.8°. However, there was little tolerance for error without the risk of violating the articular cartilage. With transverse osteotomy, averaging 18° ± 10.6° in the coronal plane, there is less risk of damaging the articular cartilage. CONCLUSIONS: Transverse osteotomy perpendicular to the posterior surface of the ulna aiming at the visible bare area on the medial and lateral sides of the greater sigmoid notch may reduce the chances of violating the nonvisible articular cartilage of the proximal ulna. Based on the findings of this study, if chevron osteotomy is used, a shallow apex distal angle of more than 110° is recommended. CLINICAL RELEVANCE: This study provides intraoperative landmarks to guide surgeons performing olecranon osteotomies to stay within the bare area.

Transposon insertions within alleles of BnaFT.A2 are associated with seasonal crop type in rapeseed.

KEY MESSAGE: We identified two new transposon insertions within the promoter of BnaFT.A2 in addition to an existing 288 bp MITE within the second intron. Each insertion event corresponds to a distinct BnaFT.A2 haplotype and is closely associated with established crop seasonal ecotypes. Florigen, encoded by FLOWERING LOCUS T (FT), plays key roles not only as a flowering hormone, but also a universal growth factor affecting several aspects of plant architecture. In rapeseed, BnaFT.A2 has been revealed as one of the major loci associated with flowering time and different ecotypes. However, it is unclear how allelic variations of BnaFT.A2 affect its function in flowering time regulation and beyond. In this study, we confirmed an existing 288 bp miniature inverted-repeat transposable element (MITE) insertion within the second intron and identified two new insertions within the promoter of BnaFT.A2-a 3971 bp CACTA and a 1079 bp Helitron. Each insertion event corresponds to a distinct BnaFT.A2 haplotype and is closely associated with established crop seasonal ecotypes. These alleles have similar tissue-specific expression patterns but discrete transcriptional patterns tightly associated with rapeseed flowering time and ecotype. RNAi lines and mutants of BnaFT.A2 flowered significantly later than controls. Differentially expressed genes (DEGs), identified in transcriptomic profiling of seedling leaves from two loss-of-function mutants (Bnaft.a2-L1 and Bnaft.a2-L2) compared with controls, indicated significant enrichment for hormone metabolic genes and roles related to plant cell wall synthesis and photosynthesis. Plants with loss-of-function BnaFT.A2 had smaller leaves and lower net photosynthetic rate compared to controls. These findings not only further clarify the genetic basis of flowering time variation and ecotype formation in B. napus, but also provide an additional toolbox for genetic improvement of seasonal adaptation and production.

Establishing a Common Nutritional Vocabulary - From Food Production to Diet.

Informed policy and decision-making for food systems, nutritional security, and global health would benefit from standardization and comparison of food composition data, spanning production to consumption. To address this challenge, we present a formal controlled vocabulary of terms, definitions, and relationships within the Compositional Dietary Nutrition Ontology (CDNO, www.cdno.info) that enables description of nutritional attributes for material entities contributing to the human diet. We demonstrate how ongoing community development of CDNO classes can harmonize trans-disciplinary approaches for describing nutritional components from food production to diet.

Systematic trait dissection in oilseed rape provides a comprehensive view, further insight, and exact roadmap for yield determination.

BACKGROUND: Yield is the most important and complex trait that is influenced by numerous relevant traits with very complicated interrelations. While there are a large number of studies on the phenotypic relationship and genetic basis of yield traits, systematic studies with further dissection focusing on yield are limited. Therefore, there is still lack of a comprehensive and in-depth understanding of the determination of yield. RESULTS: In this study, yield was systematically dissected at the phenotypic, genetic to molecular levels in oilseed rape (Brassica napus L.). The analysis of correlation, network, and principal component for 21 traits in BnaZN-RIL population showed that yield was determined by a complex trait network with key contributors. The analysis of the constructed high-density single nucleotide polymorphism (SNP) linkage map revealed the concentrated distribution of distorted and heterozygous markers, likely due to selection on genes controlling the growth period and yield heterosis. A total of 134 consensus quantitative trait loci (QTL) were identified for 21 traits, of which all were incorporated into an interconnecting QTL network with dozens of hub-QTL. Four representative hub-QTL were further dissected to the target or candidate genes that governed the causal relationships between the relevant traits. CONCLUSIONS: The highly consistent results at the phenotypic, genetic, and molecular dissecting demonstrated that yield was determined by a multilayer composite network that involved numerous traits and genes showing complex up/down-stream and positive/negative regulation. This provides a systematic view, further insight, and exact roadmap for yield determination, which represents a significant advance toward the understanding and dissection of complex traits.

Nonoperative treatment of lateral epicondylitis: a systematic review and meta-analysis.

BACKGROUND: There is an ongoing controversy regarding the nonoperative treatment of lateral epicondylitis. Given that the evidence surrounding the use of various treatment options for lateral epicondylitis has expanded, an overall assessment of nonoperative treatment options is required. The purpose of this systematic review and meta-analysis was to compare physiotherapy (strengthening), corticosteroids (CSIs), platelet-rich plasma (PRP), and autologous blood (AB) with no active treatment or placebo control in patients with lateral epicondylitis. METHODS: MEDLINE, Embase, and Cochrane were searched through till March 8, 2021. Additional studies were identified from reviews. All English-language randomized trials comparing nonoperative treatment of patients >18 years of age with lateral epicondylitis were included. RESULTS: A total of 5 randomized studies compared physiotherapy (strengthening) with no active treatment. There were no significant differences in pain (mean difference: -0.07, 95% confidence interval [CI]: -0.56 to 0.41) or function (standardized mean difference [SMD]: -0.08, 95% CI: -0.46 to 0.30). Seven studies compared CSI with a control. The control group had statistically superior pain (mean difference: 0.70, 95% CI: 0.22 to 1.18) and functional scores (SMD: -0.35, 95% CI: -0.54 to -0.16). Two studies compared PRP with controls, and no differences were found in pain (SD: -0.15, 95% CI: -1.89 to 1.35) or function (SMD: 0.14, 95% CI: -0.45 to 0.73). Three studies compared AB with controls, and no differences were observed in pain (0.49, 95% CI: -2.35 to 3.33) or function (-0.07, 95% CI: -0.64 to 0.50). DISCUSSION: The available evidence does not support the use of nonoperative treatment options including physiotherapy (strengthening), CSI, PRP, or AB in the treatment of lateral epicondylitis.

Genetic Control of Seed Phytate Accumulation and the Development of Low-Phytate Crops: A Review and Perspective.

Breeding low phytic acid (lpa) crops is a strategy that has potential to both improve the nutritional quality of food and feed and contribute to the sustainability of agriculture. Here, we review the lipid-independent and -dependent pathways of phytate synthesis and their regulatory mechanisms in plants. We compare the genetic variation of the phytate concentration and distribution in seeds between dicot and monocot species as well as the associated temporal and spatial expression patterns of the genes involved in phytate synthesis and transport. Quantitative trait loci or significant single nucleotide polymorphisms for the seed phytate concentration have been identified in different plant species by linkage and association mapping, and some genes have been cloned from lpa mutants. We summarize the effects of various lpa mutations on important agronomic traits in crop plants and propose SULTR3;3 and SULTR3;4 as optimal target genes for lpa crop breeding.

Transposable element insertion: a hidden major source of domesticated phenotypic variation in Brassica rapa.

Transposable element (TE) is prevalent in plant genomes. However, studies on their impact on phenotypic evolution in crop plants are relatively rare, because systematically identifying TE insertions within a species has been a challenge. Here, we present a novel approach for uncovering TE insertion polymorphisms (TIPs) using pan-genome analysis combined with population-scale resequencing, and we adopt this pipeline to retrieve TIPs in a Brassica rapa germplasm collection. We found that 23% of genes within the reference Chiifu-401-42 genome harbored TIPs. TIPs tended to have large transcriptional effects, including modifying gene expression levels and altering gene structure by introducing new introns. Among 524 diverse accessions, TIPs broadly influenced genes related to traits and acted a crucial role in the domestication of B. rapa morphotypes. As examples, four specific TIP-containing genes were found to be candidates that potentially involved in various climatic conditions, promoting the formation of diverse vegetable crops in B. rapa. Our work reveals the hitherto hidden TIPs implicated in agronomic traits and highlights their widespread utility in studies of crop domestication.

Overhead arm positioning in the rehabilitation of elbow dislocations: An in vitro biomechanical study.

STUDY DESIGN: In vitro biomechanical study. INTRODUCTION: Elbow stiffness is a common complication following elbow dislocation. Overhead exercises have been proposed to initiate early motion to reduce stiffness through employing gravity to stabilize the elbow. The implications of this position with regard to elbow kinematics after dislocation have not been reported. PURPOSE OF THE STUDY: To determine the influence of the overhead position on elbow stability following combined medial and lateral collateral ligament (MCL and LCL) injuries. METHODS: Passive and simulated active extension were performed on 11 cadaveric elbows with the arm in the overhead, dependent, and horizontal positions and with the forearm in pronation, neutral, and supination. Internal-external rotation (IER) and varus-valgus angulation (VVA) of the ulnohumeral joint were assessed for the intact elbow and after simulated MCL-LCL injury. Repeated-measures analyses of variance were conducted to analyze the effects of elbow state, arm position, forearm rotation, and extension angle. RESULTS: During passive extension with the arm overhead, the pronated position resulted in more internal rotation than supination (-2.6 ± 0.7°, P = .03). There was no effect of forearm rotation on VVA. The overhead position increased internal rotation relative to the dependent position when the forearm was neutral (-8.5 ± 2.5°, P = .04) and relative to the horizontal position when the forearm was supinated (-12.7 ± 2.2°, P= .02). During active extension, pronation increased valgus angle compared to the neutral (+1.2 ± 0.3°, P= .04) and supinated (+1.5 ± 0.4°, P= .03) positions, but did not affect IER. There was no difference between active and passive motion with the arm overhead (P > .05). DISCUSSION: Movement of the injured elbow in the overhead position most closely replicated kinematics of the intact elbow compared to the other arm positions. CONCLUSIONS: Overhead elbow extension results in similar kinematics between an intact elbow and an elbow with MCL and LCL tears. As such, therapists might consider early motion in this position to reduce the risk of elbow stiffness after dislocation.

Outcomes of radial head implants in total elbow arthroplasty.

BACKGROUND: There is no consensus on the management of the radial head in total elbow arthroplasty (TEA). In 3-part TEA designs, options include radial head retention, excision, or arthroplasty. Biomechanical studies suggest improved varus-valgus stability with radial head implants in unlinked total elbows. Unfortunately, complications with radial head implants have been common with historical designs. The aim of this study was to evaluate the clinical and radiographic outcomes of radial head implants in a current 3-part TEA and identify risk factors for mechanical failure. METHODS: We performed a retrospective review of radial head implants with a 3-part convertible TEA from 2001 to 2016. Clinical outcomes, functional scores, and radiographic outcomes were recorded. The preoperative radiocapitellar alignment was measured using the radiocapitellar ratio (RCR). Statistics include descriptive statistics, t tests, logistic regression, and Kaplan-Meier survival curves. RESULTS: We identified 44 TEAs in 40 patients, with a mean follow-up period of 7.2 years. The average age at surgery was 58 ± 11 years; 80% of the TEAs were performed in women. The indication for surgery was rheumatoid arthritis in 86%; of the implants, 61% were unlinked. The average preoperative RCR was 10.7 ± 17.9. Postoperatively, 2 radial head implants (5%) were subluxated, 6 (14%) were dissociated, and 2 (5%) were dissociated with implant dislocation on radiographic review. The revision rate for radial head subluxation, dissociation, or dislocation was 7% (n = 3). Univariate logistic regression showed that male sex (P = .002), abnormal preoperative RCR (P = .02), linked implant (P = .03), and older age (P = .04) were risk factors for radial head subluxation, dissociation, or implant dislocation. A multivariate model with all 4 variables did not demonstrate statistical significance. CONCLUSION: The incidence of radial head arthroplasty subluxation, dissociation, or implant dislocation was high (23%). In a univariate logistic regression model, male sex, abnormal preoperative RCR, and linked implants were all statistically significant risk factors for mechanical failure of the radial head implant. Our multivariate model did not show any statistically significant independent risk factors. Polyethylene wear or loosening of the radial head implants was not observed in this study; failure of the bipolar linkage was the principal mode of failure. Although further study is required, caution should be used when considering inserting a radial head implant in male patients with significant preoperative radiocapitellar malalignment. Radial head subluxation or dissociation is not an absolute indication for revision in an asymptomatic patient. Improvements in radial head implant designs in TEA are needed.

Integrating a genome-wide association study with transcriptomic data to predict candidate genes and favourable haplotypes influencing Brassica napus seed phytate.

Phytate is the storage form of phosphorus in angiosperm seeds and plays vitally important roles during seed development. However, in crop plants phytate decreases bioavailability of seed-sourced mineral elements for humans, livestock and poultry, and contributes to phosphate-related water pollution. However, there is little knowledge about this trait in oilseed rape (Brassica napus). Here, a panel of 505 diverse B. napus accessions was screened in a genome-wide association study (GWAS) using 3.28 × 106 single-nucleotide polymorphisms (SNPs). This identified 119 SNPs significantly associated with phytate concentration (PA_Conc) and phytate content (PA_Cont) and six candidate genes were identified. Of these, BnaA9.MRP5 represented the candidate gene for the significant SNP chrA09_5198034 (27 kb) for both PA_Cont and PA_Conc. Transcription of BnaA9.MRP5 in a low-phytate variety (LPA20) was significantly elevated compared with a high-phytate variety (HPA972). Association and haplotype analysis indicated that inbred lines carrying specific SNP haplotypes within BnaA9.MRP5 were associated with high- and low-phytate phenotypes. No significant differences in seed germination and seed yield were detected between low and high phytate cultivars examined. Candidate genes, favourable haplotypes and the low phytate varieties identified in this study will be useful for low-phytate breeding of B. napus.

Functional homoeologous alleles of CONSTANS contribute to seasonal crop type in rapeseed.

KEY MESSAGE: Two CO paralogs in Brassica napus were confirmed and shown distinct expression pattern and function in promoting flowering and allelic variation s within BnaCO.A10 were found closely associated with ecotype divergence. CONSTANS (CO) is a key gene that responds to photoperiod and in Arabidopsis can promote flowering under long-day (LD) conditions. Brassica napus L. is a major oil crop and close relative of Arabidopsis, and arose via allopolyploidization from the diploids B. rapa (A genome) and B. oleracea (C genome). In this study, we confirmed that B. napus has two CO genes located on the A10 (BnaCO.A10) and C9 (BnaCO.C9) chromosomes. Significant differences in level and temporal pattern of transcription, as well as in protein function, of these homoeologous may have resulted from sequence variation in the promoter as well as in the coding region. Apart from two insertions of 527 bp and 2002 bp in the promoter of BnaCO.C9 that function as transcriptional enhancers, this gene is otherwise highly conserved in both promoter and coding region. However, BnaCO.A10 was classified into two haplotypes and transgene analysis in Arabidopsis and backcross analysis in rapeseed indicated that the winter-type haplotype had a greater effect in promoting flowering than the spring type. We discuss the contribution of CO alleles to species evolution, and for eco-geographic radiation following crop domestication, alongside scope for managing this locus in future breeding.