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Our recent work identified store-operated Ca(2+) entry (SOCE) as the critical Ca(2+) source required for the induction of human myoblast differentiation (Darbellay, B., Arnaudeau, S., König, S., Jousset, H., Bader, C., Demaurex, N., and Bernheim, L. (2009) J. Biol. Chem. 284, 5370-5380). The present work indicates that STIM2 silencing, similar to STIM1 silencing, reduces myoblast SOCE amplitude and differentiation. Because myoblasts in culture can be induced to differentiate into myotubes, which spontaneously contract in culture, we used the same molecular tools to explore whether the Ca(2+) mechanism of excitation-contraction coupling also relies on STIM1 and STIM2. Live cell imaging of early differentiating myoblasts revealed a characteristic clustering of activated STIM1 and STIM2 during the first few hours of differentiation. Thapsigargin-induced depletion of endoplasmic reticulum Ca(2+) content caused STIM1 and STIM2 redistribution into clusters, and co-localization of both STIM proteins. Interaction of STIM1 and STIM2 was revealed by a rapid increase in fluorescence resonance energy transfer between CFP-STIM1 and YFP-STIM2 after SOCE activation and confirmed by co-immunoprecipitation of endogenous STIM1 and STIM2. Although both STIM proteins clearly contribute to SOCE and are required during the differentiation process, STIM1 and STIM2 are functionally largely redundant as overexpression of either STIM1 or STIM2 corrected most of the impact of STIM2 or STIM1 silencing on SOCE and differentiation. With respect to excitation-contraction, we observed that human myotubes rely also on STIM1 and STIM2 to refill their endoplasmic reticulum Ca(2+)-content during repeated KCl-induced Ca(2+) releases. This indicates that STIM2 is a necessary partner of STIM1 for excitation-contraction coupling. Thus, both STIM proteins are required and interact to control SOCE during human myoblast differentiation and human myotube excitation-contraction coupling.

As the result of improved bacteriological techniques, Kingella kingae is a slow-growing Gram-negative coccobacillus that is emerging as an important cause of spondylodiscitis in children younger than 3 years of age. The high pharyngeal carrier rates of this slow-growing Gram-negative coccobacillus combined with the low incidence of identified K. kingae infections is possibly explained by a low virulence of this bacterium. The use of specific real-time polymerase chain reaction (PCR) on blood samples and throat swabs opens new prospects in the bacteriological investigations of young children suspected to have spondylodiscitis, an approach that could prevent, in the future, unnecessary invasive interventions.

Broad-range PCR followed by sequencing identifies bacterial pathogens, even in challenging settings such as patients receiving antibiotics or infected with fastidious or non-cultivable organisms. The major problem with broad-range PCR is the risk of sample contamination. Risk is present at every step of the procedure, starting from sample collection. Contaminating bacterial DNA may be present not only in laboratory reagents but also at the surface of plastic consumables and containers used for specimen drawing and transport to the diagnostic laboratory. Contaminating DNA is amplified efficiently, leading to false-positive results. Thus, high specificity depends on eliminating such spurious targets, an awkward problem given the abundance of such targets and a highly sensitive method that detects very small numbers of molecules. Several investigators have reported strategies for eliminating the amplification of contaminating DNA sequences. So far, none of these methods has been entirely effective and reproducible. Here we describe a method that uses Exonuclease III (ExoIII) to disable contaminating sequences from acting as templates, while maintaining the high sensitivity of PCR for pathogen DNA. We use this assay in 144 clinical specimens from normally sterile sites, identifying pathogens from 24 (17%). Conventional methods identified pathogens in only four of these specimens, all of which were positive for the same pathogen by PCR. Compared with conventional methods, broad-range PCR with ExoIII pre-treatment of reagents substantially improves the diagnostic yield of bacterial pathogen identification from normally sterile sites.

Kingella kingae is an emerging pathogen that is recognized as a causative agent of septic arthritis and osteomyelitis, primarily in infants and children. The bacterium is best detected by rapid inoculation in blood culture systems or by real-time PCR assays. Pathogenesis of the agent was linked recently to the production of a potent cytotoxin, known as RTX, which is toxic to a variety of human cell types. The locus encoding the RTX toxin is thought to be a putative virulence factor, and is, apparently, essential for inducing cytotoxic effects on respiratory epithelial, synovial and macrophage-like cells. Herein, we describe a novel real-time PCR assay that targets the RTX toxin gene and illustrate its use in two clinical cases. The assay exhibited a sensitivity of 30 c.f.u., which is 10-fold more sensitive than a previously published semi-nested broad-range 16S rRNA gene PCR, and showed no cross-reactivity with several related species and common osteoarticular pathogens.

Background: Patient controlled epidural analgesia (PCEA) is uncommon in pediatric anesthesia. Because PCEA offers superior pain control compared with continuous epidural infusions in adults, we prospectively evaluated the analgesia efficacy and safety of PCEA in children and adolescents following extensive spinal surgery., Methods: Following ethics committee approval, 100 consecutive children [age median (range) 14 (6-19) years] undergoing spinal surgery were studied until the seventh postoperative day, and 98 children received a PCEA. One or two epidural catheters were positioned under direct vision by the surgeon based on the number of vertebral segments operated upon. The epidural solution consisted of bupivacaine 0.0625%, fentanyl 1 microg.ml(-1) and clonidine 0.6 microg.ml(-1), delivered at a basal rate of 0.2 ml.kg(-1).h(-1) and a PCEA dose of 0.1 ml.kg(-1).h(-1)(max. 2 h(-1)). On the fourth postoperative day, PCEA was stopped and analgesia was continued with patient controlled analgesia (PCA) with morphine., Results: During the PCEA regimen, the maximal scores of the revized facial scale were below 4 at rest with a very high satisfaction rate (>90%). Pain scores were higher during mobilization on the first postoperative day and when PCEA was switched to PCA. The overall incidence of adverse events was low and consisted primarily of technical problems and postoperative nausea and vomiting. Only two children experienced a complication requiring the discontinuation of the PCEA but there were no consequent adverse sequelae., Conclusions: The present study demonstrates that PCEA provides excellent pain relief following extensive spinal surgery and is associated with a low incidence of adverse events. The use of PCEA should be encouraged in children and adolescents following extensive spinal surgery.

Purpose: The treatment of an unrecognized Monteggia lesion continues to pose a therapeutic challenge, as evidenced by the variety of surgical techniques described. Moreover, there are high complication and redislocation rates following surgery. This report concerns a surgical technique to reduce a chronic dislocation of the radial head utilizing an ulnar osteotomy and internal fixation., Methods: Six consecutive cases of missed Monteggia lesions were treated in our institution between August 2001 and September 2003. Patient mean age was 6.5 (range 4-8) years, and the mean interval between injury and surgical procedure was 17 (range 1-49) months. Surgery consisted of an ulnar osteotomy with angulation and lengthening, bone grafting at the osteotomy site, and internal fixation. Open reduction of the radial head, repair or reconstruction of the annular ligament or temporary fixation of the radial head with a transarticular wire was not undertaken. Cast immobilization with the forearm in neutral rotation was maintained for 2 weeks., Results: There was one case of nonunion. At an average follow-up of 3 (range 1.5-4.4) years, all patients had regained painless function of the forearm, good range of elbow and forearm motion, and maintenance of the radial head reduction., Conclusions: Both angulation and elongation of the ulna are required to allow for reduction of the radial head. We do not see any indication for procedures directed at the radio-capitellar joint.

We report 4 cases of nutcracker fractures of the cuboid resulting from equestrian sport in pediatric population. These lesions are often consistent with a trauma in forced abduction of the forefoot. The particular mechanism of the cuboid fracture due to horseback riding in children is discussed. The methods used to radiographically evaluate the compression fracture of the cuboid and its associated injuries are presented. Left untreated, these fractures can lead to severe alterations in foot mechanics and function, such as to severe pain. In addition, the surgical treatment to correct the nutcracker fracture of the cuboid in our patients is presented.

Tibial hemimelia with ectrodactyly is reported for the first time in monozygotic female twins with a positive family history for limb anomalies. This very rare autosomal dominant condition is known to be associated with a highly variable phenotype, as illustrated by the distinct clinical presentations, despite identical genotype.

The aim of this study was to compile specific foot injuries occurring in pediatric patients that result from equestrian sports and to highlight the importance of wearing adequate riding boots to protect the feet. During a 12-year period, 258 children were admitted to Children's Hospital of Geneva for injuries resulting from horseback riding. Amongst these children, 8 sustained foot lesions that required hospital admission. Four children had compression-type fractures of the cuboid (nutcracker fracture of the cuboid) associated with other complex midfoot fractures, 2 had Lisfranc fracture dislocations, 1 had a fracture of the talus with associated intern malleolar fracture, and the last had a fracture of the 5 metatarsals with lateral displacement. All the noted lesions complied with the same traumatic mechanisms. The horse fell on the patient, and the child's foot, entrapped in the stirrup, was caught in between the animal and the ground. The forefoot was bent by indirect violence in abduction by the stirrup, which acted as a fulcrum. Serious foot injuries may occur in children during equestrian activities. These lesions may be very disabling. Therefore, it is important for doctors, instructors, and parents to promote the use of appropriate safety equipment, including strengthened riding boots and safety stirrups.

Legg-Calvé-Perthes disease remains indefinite from an etiologic point of view and unforeseable in its evolution. The evolution depends on the extent of epiphyseal involvement and the age of the child. It may safely be stated that the more extensive the epiphyseal involvement, the more compromised is the prognosis. Also the older the child, the more the femoral head remoulding will be limited. Preserving articular mobility and containing the head within the depth of acetabulum constitute the mainstay of treatment aiming for a femoral head as spherical as possible upon completion of growth. At the end of growth spherical or ovoid heads will cause no or few problems, however strongly deformed femoral heads will evolve into early hip arthritis. The early recognition of which hip will profit from which treatment, constitutes the major difficulty of the therapeutic process.

Calcaneus secundarius is an accessory ossicle of the anterior calcaneal facet identified in up to 5% of the population. Calcaneus secundarius rarely leads to symptoms, but its presence may generate pain around the ankle. The purpose of this case report is to describe this atypical accessory ossicle, which can mimic a calcaneonavicular coalition, and to explain the clinical approach to reach a diagnosis and determine treatment. The authors report the case of a 13-year-old girl who sustained several lateral sprains of the right ankle and had local chronic pain. Clinical findings were consistent with calcaneonavicular coalition but radiographic examinations revealed a calcaneus secundarius. The location of this ossicle may limit the range of motion of the subtalar joint, mimicking a calcaneonavicular coalition. Surgical excision of this bulky accessory ossicle was performed, and this treatment fully resolved the pain and improved subtalar motion.

Purpose of the Study: The incidence of neurological lesions after hip surgery is underestimated because of variable clinical expression and functional disorders resulting from nerve injury and often considered to be the normal course after hip surgery. The incidence of nerve lesions after hip surgery for fractures of the proximal femur remains to be detailed., Material and Method: This retrospective study included 20 cases of sciatic nerve injury following hip surgery (2554 THA, 394 revision THA, 4632 osteosyntheses or hemiarthroplasties of the proximal femur). We noted degree of recovery of the neurological deficit and deterioration of the patients' quality-of-life. The prognosis was determined on the basis of clinical and electromyographic data., Results: The incidence of nerve injury after hip surgery was 0.5% after THA, 1% after revision THA, and 0.08% after osteosynthesis or hemiarthroplasty of the proximal femur. The etiological factor remained unknown in the majority of the cases. The prognosis was tightly related to the type of neurological lesion as defined by the electrophysiological study. Three revision procedures were performed: two for drainage of a compressive hematoma and one to release the sciatic nerve (neurolysis). The prognosis depended on the type of neurological lesion as established by the electroneuromyographic study., Discussion: Severe axonotmesis is associated with late recovery, generally incomplete recovery, and poor long-term functional outcome.

A 13-year-old boy sustained an avulsion fracture of the left greater trochanter eight months after surgical stabilisation of a slipped capital femoral epiphysis on the same side. In this specific case, avulsion of the greater trochanter after slipping of the capital femoral epiphysis may have been facilitated by weakening of the trochanteric physis.

The authors report the case of a five and a half year-old-boy with symptomatic MRI abnormalities of the ischiopubic synchondrosis. The concept of "ischiopubic osteochondritis" is reviewed in the light of modern imaging, and the importance of its differentiation from different pathological entities such as osteomyelitis, tumour, fracture or other pathologic entities is recalled.

This study aimed at assessing the prevalence of complications encountered during prolonged intravenous antibiotic (AB) therapy when treating acute osteoarticular (OA) infections in children. We reviewed retrospectively 60 paediatric patients treated in our department between 1988 and 1998 for acute osteoarticular infections (27 with acute haematogenous osteomyelitis, 25 with septic arthritis and 8 with septic osteoarthritis). C-reactive protein, erythrocyte sedimentation rate (ESR), and full blood count were monitored during the entire treatment. Body temperature was recorded three times per day until the fever subsided, and then daily during the remaining hospitalisation. Finally, we listed complications related to the antibiotic therapy and those linked to the presence of a venous catheter. Seventeen allergic reactions to drugs were recorded during the intravenous AB therapy. This complications occurred on average after 24.4 +/- 4.4 days of treatment. The clinical manifestations most often encountered were a delayed rise in temperature and cutaneous symptoms. Blood tests showed an isolated increase in the ESR and eosinophilia (> 1000 eosinophils/ml). Four venous catheters had to be removed, in two cases owing to their obstruction and in two cases owing to an infection. Prolonged intravenous AB therapy is not without complications due to its duration and its mode of administration. Drug allergies to AB constitute a major complication of the treatment. They may render the treatment of subsequent infections problematic and expose these patients to major allergic reactions if they accidentally encounter the molecule incriminated. Moreover, the anaesthetics required to insert a central venous catheter and the need to leave it in place for a prolonged duration constitute another source of potential complications. The duration of i.v. AB therapy could therefore be shortened if the clinical and biological evolution is favourable and the pathogen is identified.

Purpose of the Study: Bone and joint infections are challenging therapeutic situations requiring rapid antibiotic therapy as soon as bacteriology specimens have been obtained. Laboratory tests (C reactive protein, erythrocyte sedimentation rate, white cell count) and clinical findings are used to assess therapeutic efficacy. Most of the clinical signs however, particularly in children or after a surgical procedure, are not explicit enough to allow proper assessment of the clinical course under antibiotic therapy. Body temperature is the only parameter currently used in routine practice. But the measurement of body temperature is not always reliable and variations observed during treatment should not always be attributed to treatment failure. The purpose of this work was to assess the significance of changes in body temperature observed in children given effective intravenous antibiotic treatment for bone and joint infections., Material and Methods: We reviewed retrospectively the files of 60 children treated in our unit for acute bone and joint infections. The patients had acute hematogeneous osteomyelitis (n=27), septic arthritis (n=25), and infectious osteoarthritis (n=8). A bacterial strain was identified on cultures of blood, joint fluid, or metaphysis puncture samples in all cases. Blood test results (C-reactive protein, erythrocyte sedimentation rate, white cell count) were recorded during treatment. Body temperature was recorded three times a day until normalization then daily until discharge. We searched for correlations between variations in the temperature curve observed during treatment and blood test results., Results: Ninety percent of the children had fever at admission (mean 39.1 degrees C). Among the six children without fever, the temperature rose in 5 during the first 48 hours of hospitalization. Even when the treatment was effective, apyrexia was achieved slowly, on the average after 8 days of antibiotic treatment. We also observed that the peak temperature occurred during the first 5 days of antibiotic treatment considered effective. C-reactive protein level normalized within a satisfactory time (10.5 days), reflecting the efficacy of the antibiotics., Discussion: The efficacy of antibiotic treatment must always be verified in patients with acute bone and joint infections. Generally, biological parameters are used to monitor efficacy. Currently, C-reactive protein appears to be the most reliable parameter to assess efficacy, its rapid decline reflecting clinical cure. Erythrocyte sedimentation rate and white cell counts are poor surveillance parameters. Finally, body temperature is not a specific surveillance parameter and persistent fever during treatment does not necessarily signify ineffective antibiotic treatment. In light of this fact, body temperature should always be compared with C-reactive protein level to draw any conclusion concerning therapeutic failure.

Purpose of the Study: Between 1990 and 1998, 110 knee arthroscopies were performed in children. We analyzed the epidemiology and diagnostic data and studied the correlation between clinical and radiographic findings and the final diagnosis after arthroscopy in order to establish a consensus on use of knee arthroscopy in children., Material and Methods: We made a retrospective analysis of 110 knee arthroscopies performed in children, classing the patients in three age groups: 0-5 years, 5-10 years, 10-17 years. Clinical and radiological findings were compared with the arthroscopy findings., Results: One or more arthroscopies were performed in 56 boys and 48 girls. Mean age at the time of the procedure was 12 years 4 months. There were 11 children aged 0-5 years, 14 aged 5-10 years and 85 aged 10-17 years. The main pathology was arthritis in the 0-5 year and 5-10 year age groups. Trauma was more frequent in the older children. Knee arthroscopy was found to be normal in 19 cases., Discussion: For most surgery teams, arthroscopy is indicated for arthritis of the knee. Arthroscopy may also be needed for hemarthrosis. In these contexts, arthroscopy is both a diagnostic and therapeutic procedure. Our analysis demonstrates that emergency arthroscopy is only warranted for free floating osteochondral fractures and fractures of the tibial articular surfaces, with the exception of the tibial spines. Arthroscopy may be performed later in other cases after careful physical examination and radiographic series. We had 19 normal arthroscopies and 10 that showed femoropatellar chondropathies and plicas that could explain knee pain. We recommend arthrography before arthroscopy to avoid unnecessary procedures., Conclusion: Arthritis of the knee is an excellent indication for arthroscopy. Painful and acute hemarthrosis requires attentive physical exams and x-rays before making the decision for surgery.

Focal fibrocartilaginous dysplasia is a rare and benign condition associated with unilateral tibia vara in toddlers. Three additional cases are reported in children aged 17, 18 and 26 months with spontaneous resolution. The authors discuss, based on a meta-analysis, the natural history of the disorder and review the diagnostic and pathophysiological problems. Since spontaneous remodeling of varus angulation and healing of the bony defect can be expected, biopsy and surgical intervention should be avoided.

Fourteen extension osteotomies were performed in 13 patients with angular metacarpal malunion. Surgery was indicated by the limitation of mobility, the reduction in gripping capacity, and pain following digitopalmar grasping movements. After surgery, the patients regained good articular mobility. However, in 60% of cases a teno-arthrolysis was required upon removal of consolidation hardware to restore digital function. The operation allowed pain relief in two-thirds of the patient population; in the remaining subjects, pain was experienced when making grasping movements. At the final examination, in the majority of cases gripping strength was similar to that of the contralateral hand. In conclusion, correction of angular malunion by extension osteotomy is a demanding procedure, and whenever possible should be avoided by a precise reduction of the metacarpal fracture during initial surgery. A fractured metacarpal with a palmar angulation of over 15 degrees should systematically be reduced and fixed if unstable.