Effects of simulated radioulnar synostosis on supination and pronation in cats. A cadaveric study.

OBJECTIVE: To evaluate the effect of an induced synostosis with a screw on pronation and supination in cats. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: A total of 58 feline forelimbs. METHODS: A total of 58 cadaveric feline thoracic limbs were mounted on a custom-built jig with the elbow and carpus flexed at a 90° angle. To exclude any orthopedic disease, radiographs of the forelimbs were performed prior to the mechanical tests. Radioulnar synostosis was imitated with a 2 mm cortical screw through the radius into the ulna in the proximal (Group P; n = 54), middle (Group M; n = 52), and distal (Group D; n = 53) radial diaphysis. The angles of pronation and supination were recorded after manually applying a two-finger tight rotational force to the metacarpus. Rotational tests were performed without a screw (Group N) and with a screw in each of the aforementioned positions. Pairwise comparisons between the groups were performed based on their angles of rotation with a paired t-test with the Benjamini-Hochberg procedure and a mixed model ANOVA. RESULTS: Mean angles of rotation decreased between Group N (129.5 ± 15.9°) and all groups with imitated radioulnar synostosis to a mean angle of 37.5 ± 14.5° (p < .0001). Mean angles of rotation did not differ between the groups with imitated radioulnar synostosis. CONCLUSION: Induced radioulnar synostosis decreases antebrachial rotation by more than two-thirds, regardless of location. CLINICAL SIGNIFICANCE: Implants fixating the radius to the ulna should be avoided in cats, regardless where they are located along the radial diaphysis.

Homozygous SMAD6 variants in two unrelated patients with craniosynostosis and radioulnar synostosis.

BACKGROUND: SMAD6 encodes an intracellular inhibitor of the bone morphogenetic protein (BMP) signalling pathway. Until now, rare heterozygous loss-of-function variants in SMAD6 were demonstrated to increase the risk of disparate clinical disorders including cardiovascular disease, craniosynostosis and radioulnar synostosis. Only two unrelated patients harbouring biallelic SMAD6 variants presenting a complex cardiovascular phenotype and facial dysmorphism have been described. CASES: Here, we present the first two patients with craniosynostosis harbouring homozygous SMAD6 variants. The male probands, both born to healthy consanguineous parents, were diagnosed with metopic synostosis and bilateral or unilateral radioulnar synostosis. Additionally, one proband had global developmental delay. Echocardiographic evaluation did not reveal cardiac or outflow tract abnormalities. MOLECULAR ANALYSES: The novel missense (c.[584T>G];[584T>G], p.[(Val195Gly)];[(Val195Gly)]) and missense/splice-site variant (c.[817G>A];[817G>A], r.[(817g>a,817delins[a;817+2_817+228])];[(817g>a,817delins[a;817+2_817+228])], p.[(Glu273Lys,Glu273Serfs*72)];[(Glu273Lys,Glu273Serfs*72)]) both locate in the functional MH1 domain of the protein and have not been reported in gnomAD database. Functional analyses of the variants showed reduced inhibition of BMP signalling or abnormal splicing, respectively, consistent with a hypomorphic mechanism of action. CONCLUSION: Our data expand the spectrum of variants and phenotypic spectrum associated with homozygous variants of SMAD6 to include craniosynostosis.

A novel missense mutation in the MECOM gene in a Chinese boy with radioulnar synostosis with amegakaryocytic thrombocytopenia.

Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) type 2, caused by MDS1 and EVI1 complex locus (MECOM) gene mutations, is a rare inherited bone marrow failure syndrome (IBMFS) with skeletal anomalies, characterized by varying presentation of congenital thrombocytopenia (progressing to pancytopenia), bilateral proximal radioulnar synostosis, and other skeletal abnormalities. Due to limited knowledge and heterogenous manifestations, clinical diagnosis of the disease is challenging. Here we reported a novel MECOM mutation in a Chinese boy with typical clinical features for RUSAT-2. Trio-based whole exome sequencing of buccal swab revealed a novel heterozygous missense mutation in exon 11 of the MECOM gene (chr3:168818673; NM_001105078.3:c.2285G > A). The results strongly suggest that the variant was a germline mutation and disease-causing mutation. The patient received matched unrelated donor hematopoetic stem cell transplantation (HSCT). This finding was not only expanded the pathogenic mutation spectrum of MECOM gene, but also provided key information for clinical diagnosis and treatment of RUSAT-2.

Ulnar dimelia - a review of 24 cases.

Ulnar dimelia is a very rare unilateral congenital upper limb anomaly (CULA) affecting the whole extremity. Treatment remains difficult because of the complexity and multi-level involvement. Twenty-four cases with duplicated ulna, absent radius and polydactyly from seven European centres were reviewed according to a structured list of parameters. At first consultation, median age 8 months (1-178), the shoulder movement was good in 17 patients or poor in six, and the median passive elbow range of motion was 20° (0°-90°). The resting wrist position was flexed in 22/24 patients. Following stretching and splinting, elbow surgery included resection of the lateral proximal ulna in 11 patients and muscle transfers in six to improve passive movement and increase active elbow motion, respectively. Tendon transfers were performed in eight wrists and a pollicization or pseudo-pollicization in 23 patients. Overall, patients demonstrate acceptable function postoperatively. Guidelines for treatment of this severe CULA are presented.Level of evidence: IV.

Fetal hydrops caused by a novel pathogenic MECOM variant.

We report a fetus with hydrops, congenital heart disease and bilateral radioulnar synostosis caused by a novel pathogenic MECOM variant. The female fetus was referred for post-mortem examination after fetal hydrops and intrauterine death was diagnosed at 20 weeks gestation. Post-mortem examination confirmed fetal hydrops, pallor, truncus arteriosus and bilateral radioulnar synostosis. Trio whole genome sequencing analysis detected a novel de novo heterozygous pathogenic loss-of-function variant in MECOM (NM_004991), associated with a diagnosis of Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia 2 (RUSAT-2). RUSAT-2 is a variable condition associated postnatally with bone marrow failure, radioulnar synostosis and congenital anomalies. RUSAT-2 is not currently associated with a prenatal phenotype or fetal demise, and was not present on diagnostic NHS prenatal gene panels at time of diagnosis. This case highlights the diagnostic value of detailed phenotyping with post-mortem examination, and of using a broad sequencing approach.

Fracture in Humeroradial Synostosis: Description of Two Clinical Cases / Fratura em sinostose rádio-umeral: Descrição de dois casos clínicos*

Abstract Synostosis is a generic term to indicate the union of two originally separated bones. At the elbow, humeroradial or longitudinal synostosis causes significant disability, which varies depending on hand function, elbow positioning, adjacent joints mobility and contralateral limb function. It is estimated that, to date, a little more than 150 patients have been described with this deformity, which is more common in subjects with deficient ulnar formation or affected by conditions such as Antley-Bixler and Hermann syndromes. The lack of the elbow joint, with the formation of a longer bone due to humerus-radius fusion, results in stiffness. As such, it is assumed that fractures in this topography are not uncommon. However, since synostosis is rare, this lesion was only described twice in the literature. We report two patients with a fracture of the single bone formed by a humeroradial synostosis and Bayne type-IV ulnar formation failure. Both patients were treated surgically with success. We emphasize the need for adequate treatment to not compromise the daily activities of patients who are adapted to their deformity, thus avoiding worsening the function of a previously affected limb.

Resumo Sinostose é um termo genérico utilizado para indicar a união de dois ossos originalmente separados. No cotovelo, a sinostose rádio-umeral ou longitudinal causa importante incapacidade, que varia a depender da função da mão, da posição do cotovelo, da mobilidade das articulações adjacentes e da função do membro contralateral. Estima-se que um pouco mais de 150 pacientes foram descritos até hoje com essa deformidade, sendo mais frequente em portadores de deficiência de formação ulnar ou podendo fazer parte de síndromes como de Antley-Bixler e de Hermann. Devidoàrigidezcausadapelaausênciadaarticulaçãodocotovelo,queresultana formação de um osso mais longo com a fusão do úmero no rádio, presume-se que fratura nessa topografia não seja incomum. No entanto, pela raridade dessa patologia, tal lesão apresenta apenas duas descrições prévias na literatura. Relatamos os casos de dois pacientes com fratura do osso único formado pela sinostose entre o úmero e o rádio portadores de falha de formação ulnar do tipo IV de Bayne. Ambos os pacientes foram tratados de forma cirúrgica e evoluíram bem. Salientamos a necessidade do tratamento adequado para não comprometer as atividades da vida de um paciente já adaptado à deformidade, evitando piorar a função de um membro já alterado.

Congenital Proximal Radioulnar Synostosis in an Elite Athlete-Case Report.

Background and Objectives: Proximal radioulnar synostosis (PRUS) is the most frequent congenital forearm disorder, although the prevalence in the general population is rare with a few hundred cases reported. Pfeiffer, Poland, Holt-Oram, and other serious congenital syndromes contain this abnormality. Non-syndromic cases with isolated PRUS very often exhibit as SMAD6, NOG genes variants, or sex chromosome aneuploidy. A subgroup of patients with haematological abnormalities presents with HOXA11 or MECOM genes variants. Case report: We present a non-syndromic adult elite ice-hockey player with unilateral proximal radioulnar synostosis of the left forearm. In early childhood he was able to handle the hockey stick only as a right-handed player and the diagnosis was set later at the age of 8 years due to lack of supination. Cleary-Omer Type III PRUS was found on x-ray with radial head hypoplasia and mild osteophytic degenerative changes of humeroulnar joint. Since the condition had minimal impact on sports activities, surgical intervention was not considered. The player continued his ice-hockey career at the top level and joined a national team for top tournaments. Upper extremity function assessment with questionnaires and physical testing resulted in minimal impairment. The most compromised tool was the Failla score with 10 points from a total of 15. Genetic testing with Sanger sequencing revealed no significant pathogenic variant in SMAD6, NOG, and GDP5 genes. No potentially pathogenic copy number variants were detected by array-based comparative genomic hybridization. Conclusions: In the reported case, the ability of an athlete to deal with an anatomic variant limiting the forearm supination is demonstrated. Nowadays, a comprehensive approach to rule out more complex musculoskeletal impairment and family burden is made possible by evolving genetics.

Congenital radioulnar synostosis: is prenatal diagnosis possible? - A case report.

OBJECTIVES: The main objectives of this case report are to discuss prenatal ultrasound findings of congenital radioulnar synostosis and to review the literature. CASE REPORT: A patient was diagnosed with congenital radioulnar synostosis at eight months old when parents noticed limited motions in the child's left forearm. The parent denied any traumatic or family history of bony malformations. Physical examination by a pediatric orthopedics specialist and digital radiography revealed proximal radioulnar synostosis. The case report includes perinatal course, comparison between the postnatal radiography and fetal ultrasound images. CONCLUSION: Congenital radioulnar synostosis is often associated with sex chromosome abnormalities and congenital musculoskeletal disorders or syndromes affecting limbs. Isolated congenital radioulnar synostosis is hardly diagnosed before birth, in some cases even have been neglected postnatally. Knowing the developmental milestones of the forearm and specified high-risk groups might help develop a targeted screening strategy to increase the possibility of early detection and intervention.

Evaluation of the ulna lengthening by distraction osteogenesis in congenital radial deficiency.

PURPOSE: Publications evaluating the results of the ulna lengthening in congenital radial deficiency are based only on small groups of subjects which yield statistical studies of low scientific value. The aim was to examine the effectiveness of ulna lengthening in radial longitudinal deficiency and determine the number and quality of complications based on one of the most numerous study groups described in the literature. METHODS: The material consists of a study group with 31 upper limbs of unmatured patients diagnosed with type III and IV radial longitudinal deficiency. The study group was evaluated based on the parameters known from the literature. The difficulties during elongation were classified according to Paley's classification. RESULTS: The study group contained patients with a mean age of 9 years, and the number of boys and girls was comparable. Ulna length significantly increased after elongation compared to the initial bone length. The patient's age didn't affect the ulna lengthening, and the amount of elongation didn't significantly affect the total stabilization period. However, the total stabilization time increased with increasing patient age. Difficulties affected more than half of the cases. CONCLUSIONS: Ulna elongation in congenital radial deficiency results in significant lengthening of the ulna, and thus the entire forearm, compared to the initial bone length. This technique has a high percentage of difficulty, so its use should be considered after cautious discussion with the parents and patients.

TBX3 and EFNA4 Variant in a Family with Ulnar-Mammary Syndrome and Sagittal Craniosynostosis.

Ulnar-mammary syndrome (UMS) is a rare, autosomal dominant disorder characterized by anomalies affecting the limbs, apocrine glands, dentition, and genital development. This syndrome is caused by haploinsufficiency in the T-Box3 gene (TBX3), with considerable variability in the clinical phenotype being observed even within families. We describe a one-year-old female with unilateral, postaxial polydactyly, and bilateral fifth fingernail duplication. Next-generation sequencing revealed a novel, likely pathogenic, variant predicted to affect the canonical splice site in intron 3 of the TBX3 gene (c.804 + 1G > A, IVS3 + 1G > A). This variant was inherited from the proband's father who was also diagnosed with UMS with the additional clinical finding of congenital, sagittal craniosynostosis. Subsequent whole genome analysis in the proband's father detected a variant in the EFNA4 gene (c.178C > T, p.His60Tyr), which has only been reported to be associated with sagittal craniosynostosis in one patient prior to this report but reported in other cranial suture synostosis. The findings in this family extend the genotypic spectrum of UMS, as well as the phenotypic spectrum of EFNA4-related craniosynostosis.

Severe coarctation of the aorta, developmental delay, and multiple dysmorphic features in a child with SMAD6 and SMARCA4 variants.

Pathogenic variants in SMARCA4 cause Coffin-Siris syndrome (CSS) while those in SMAD6 lead to aortic valve disease and other dysmorphisms. We identified a 6-year-old Thai boy with features of CSS alongside unusual manifestations including, very severe coarctation of the aorta (CoA) requiring coarctectomy in the neonatal period and bilateral radioulnar synostoses. Trio exome sequencing revealed that the patient harbored two de novo variants, a missense c.2475G > T, p.(Trp825Cys) in SMARCA4 and a nonsense c.652C > T, p.(Gln218Ter) in SMAD6. Both of which have never been previously reported. The clinical presentations in our patient are a result of the combinational features of each genetic variant: the SMARCA4 p.(Trp825Cys) variant leads to facial features of Coffin Siris syndrome and Dandy-Walker malformation, while the SMAD6 p.(Gln218Ter) variant underlies radioulnar synostosis. Interestingly, the severity of CoA in the proband is beyond the phenotypic spectra of each genetic variant and may be a result of the synergistic effects of both variants. Here, we report a child with variants in SMARCA4 or SMAD6 with combined features of each plus a severe CoA, possibly due to an additive effect of each variant.

Expanding the phenotypic spectrum of COLEC10-Related 3MC syndrome: A glimpse into COLEC10-Related 3MC syndrome in the Ashkenazi Jewish population.

Bi-allelic variants in COLEC11 and MASP1 have been associated with 3MC syndrome, a clinical entity made of up four rare autosomal recessive disorders: Carnevale, Mingarelli, Malpuech, and Michels syndromes, characterized by variable expression of facial dysmorphia, cleft lip/palate, postnatal growth deficiency, hearing loss, cognitive impairment, craniosynostosis, radioulnar synostosis, and genital and vesicorenal anomalies. More recently, bi-allelic variants in COLEC10 have been described to be associated with 3MC syndrome. Syndromic features seen in 3MC syndrome are thought to be due to disruption of the chemoattractant properties that influence neural crest cell migration. We identified nine individuals from five families of Ashkenazi Jewish descent with homozygosity of the c.311G > T (p.Gly104Val) variant in COLEC10 and phenotype consistent with 3MC syndrome. Carrier frequency was calculated among 52,278 individuals of Jewish descent. Testing revealed 400 carriers out of 39,750 individuals of Ashkenazi Jewish descent, giving a carrier frequency of 1 in 99 or 1.01%. Molecular protein modeling suggested that the p.Gly104Val substitution alters local conformation. The c.311G > T (p.Gly104Val) variant likely represents a founder variant, and homozygosity is associated with features of 3MC syndrome. 3MC syndrome should be in the differential diagnosis for individuals with short stature, radioulnar synostosis, cleft lip and cleft palate.

Medium to long term functional and radiographic outcomes in patients with Madelung's deformity treated by isolated or combined radioulnar osteotomy.

INTRODUCTION: Madelung's deformity is a rare congenital condition of the wrist that can cause pain, aesthetic concerns, reduced range of motion and grip strength. Currently, there is no consensus on the optimal age for surgery or whether operative procedures can be isolated or combined depending on the extent of the deformity. The main objective of our study was to analyze the postoperative functional clinical results at a minimum of 3-years follow-up in patients operated on for Madelung's deformity. The secondary objectives were (1) comparison of preoperative and postoperative radiographic parameters, and (2) to assess whether certain preoperative radiographic parameters influence the choice of surgical procedure. HYPOTHESIS: The surgery offered at our center achieves clinical and radiological result necessary for long-term activities of daily living, and varies according to the severity of the distal radial deformity. PATIENTS AND METHODS: We carried out a retrospective observational monocentric study including patients operated on between 2004 and 2016. Clinical (VAS, mobility), functional (PRWE score), and radiographic assessments were performed before and after the last follow-up. RESULTS: The study included 11 patients (12 wrists) with a mean age of 17±7.3 years and a mean follow-up of 8.1 years (4-12.3). The mean VAS was 2.3 (0-6) and the mean PRWE score was 37 (0-108). The mean flexion-extension arc was 134° and that of pronation and supination was 142°. The mean grip strength was 25.8±11.8kg. Four out of 6 radiographic criteria were significantly improved. An isolated radial osteotomy or combined radioulnar osteotomy was performed when the sagittal radial tilt was greater than 30° and protrusion of the lunate greater than 5mm, otherwise below these values, an isolated ulnar osteotomy was performed. DISCUSSION: Our center offers surgical management of Madelung's deformity by osteotomy which improves the majority of postoperative radiographic parameters and gives satisfactory clinical and radiographic results after a mean follow-up of 8.1 years. The surgery is influenced by the severity of the distal radial deformity, including protrusion of the lunate and sagittal radial tilt. LEVEL OF EVIDENCE: IV, Retrospective study.

A rare case of radius hemimelia: a case report.

Radial dysplasia congenital defect resulting in shortening of the forearm due to congenital shortening of the radius. Isidore Geoffroy Saint-Hilaire coined the term "hemimelia" around 1836-1837. Affected individuals may also have reduced limb functions abnormalities of the soft tissues, vasculature of the forearm. The management consist of splinting, stretching, and centralization. Physical therapy management plays a vital role in regaining hand function and improving quality of life. In severe cases, surgical correction such as osteotomy. Radial hemimelia is a rare disorder with 1/5000-30,000 live birth. A 16-year-old girl was admitted to Acharya Vinoba Bhave Rural Hospital (AVBRH) with complaints of weakness of the right upper limb along with a tingling sensation from the past 1 year. She was operated on with ulnar osteotomy and physical therapy management was initiated which consists of regaining mobility and strength and making the patient functionally independent. We concluded that a well structure physical therapy protocol along with medical therapy post-surgery improved the overall status of the patient.

Double-level Intraperiosteal Derotational Osteotomy for Congenital Radioulnar Synostosis.

BACKGROUND: Many operative methods have been reported for the treatment of congenital radioulnar synostosis (CRUS) and their indications remain controversial. The aim of this study is to evaluate the clinical, radiologic, and functional results of the 2-stage derotational osteotomy with periosteal preservation for CRUS in children. METHODS: From a total of 102 children with CRUS, a retrospective evaluation of 14 consecutive patients (18 forearms) who underwent 2-stage derotational osteotomy of the distal third radius and proximal third ulna with periosteal preservation, bone segment removal, morselization and grafting and cast immobilization was performed. Children with bilateral involvement and/or pronation (>60 degrees), and substantial functional limitations in daily activities were considered candidates for surgery to obtain the desired position of 0 to 20 degrees of pronation. Electronic medical records, preoperative and postoperative clinical and radiologic examinations were reviewed. Also, functional results and parental satisfaction were assessed and statistically analyzed. RESULTS: The median age at the time of surgery was 6.87 (5.02 to 11.22) years. The median follow-up was 38.62 (24.79 to 81.20) months. The median preoperative pronation deformity was 80 (70 to 90) degrees, while the final position was 0 (0 to 10) degrees of pronation ( P <0.01). Elbow flexion and extension showed no changes after surgery. All patients successfully achieved union at 8 (6 to 10) weeks. No complications were observed, and no patient required revision surgeries. The ability to perform daily activities improved markedly, and all patients were satisfied with the results of the surgery. CONCLUSIONS: Two-stage double-level intraperiosteal derotational osteotomy is a safe, simple, and effective procedure in children with CRUS with severe deformity and limitation in performing basic daily living activities. Functional improvement and patient satisfaction are total, and so far no complications have been reported. LEVEL OF EVIDENCE: Level III-treatment study, retrospective comparative study.

Treatment of Congenital Radioulnar Synostosis Using a Free Vascularized Fascia Lata Graft.

OBJECTIVE: To describe the modified mobilization surgery technique that uses a free vascularized fascia lata graft as the interposition graft, and to evaluate the outcome of this procedure in treating congenital radioulnar synostosis (CRUS). METHODS: Eleven patients (eight boys and three girls with an average age of 6.0 years) were treated using this procedure between 2012 and 2017 in our institution. Five bilateral cases (four left forearms and one right forearm were treated), and six unilateral cases (three left forearms and three right forearms) were included. All 11 cases were treated with mobilization procedure with free vascularized fascia lata as the interposition graft, and were followed-up for an average of 2.2 years (range, 2-4 years). The parental satisfaction, postoperative ankylosis at proximal radioulnar joint, and active range of forearm rotation motion (measured by physical examination) were evaluated at the last follow-up. RESULTS: The average preoperative fixed pronation angle was 67.3° (range, 20°-90°). Ipsilateral thumb hypoplasia was noted in one case, and cleft palate and bilateral thumb hypoplasia were noted in one case; none of the patients had a family history of congenital radioulnar synostosis. Pronation and supination splints were used 3 days after the operation and were worn every night for 4-6 months postoperatively. Active and passive rehabilitation for elbow flexion and forearm rotation was initiated 4 weeks postoperatively. All patients were followed up for at least 2 years (average, 26 months; range, 24-48 months). The average forearm pronation range was 39° (range, 20°-60°), and the average forearm supination range was 33.2° (range, 10°-60°) at the latest follow-up. Re-ankylosis occurred in one case. An osseous bridge developed between the radius and ulna at the osteotomy site in one case. Radial nerve paralysis developed in two cases and spontaneously resolved 2 months later. Plate breakage was noted in one case 9 weeks postoperatively; however, union was achieved 7 months later. CONCLUSION: Mobilization of proximal radioulnar synostosis using a free vascularized fascia lata graft as the interposition graft may prevent re-ankylosis and restore the forearm rotation function, making it a good option for the surgical treatment of CRUS.

An anatomical classification of congenital proximal radioulnar synostosis based on retrospective MRI measurement combined with radiography.

Existed classifications of congenital proximal radioulnar synostosis (PRUS) mainly focus on osseous changes and do not cover all types of congenital PRUS, ignoring the role and developing status of the supinator. This study aims to explore the correlation between supinator development and radiographic deformity of congenital PRUS. Pediatric patients diagnosed with congenital PRUS in two pediatric Orthopedic centers were evaluated retrospectively. MRI and radiographic images of their bilateral forearms (including normal ones) were collected. The area of supinator, extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), brachioradialis (BRAR) muscle and extensor indicis (EI) muscle were measured on each forearm. The ratios of these muscles were calculated and regarded as an indicator of the developing status of supinator muscle. Twenty-seven congenital PRUS forearms of 16 patients (average 3.45 years) were included. A new MRI & X-ray classification system was proposed to cover all types of radiographic deformity and provide a comprehensive description of supinator development. This study revealed the relation between MRI measured supinator volume and radiographic deformity of congenital PRUS. Supinator muscles were observed in all congenital PRUS cases. A novel classification was proposed, providing a more comprehensive understanding of congenital PRUS.