Bruno Dohin

Pediatric bone and joint infections caused by Panton-Valentine leukocidin-positive Staphylococcus aureus.

Background: Panton-Valentine leukocidin (PVL) is a necrotizing toxin secreted by Staphylococcus aureus. PVL-positive S. aureus osteomyelitis and arthritis have been described. Methods: We analyzed demographic, clinical, laboratory, microbiologic, and imaging data in a study group of 14 pediatric cases with PVL-positive S. aureus osteomyelitis and arthritis diagnosed between 2001 and 2005 and compared results with a control group of 17 pediatric cases of PVL-negative S. aureus osteomyelitis and arthritis treated in our institution during the same period. Treatments and outcome were studied. Results: The severity of PVL-positive S. aureus bone and joint infections was indicated by the presence of severe sepsis in all cases and of septic shock in 6 of the 14 patients. By comparison, severe sepsis was not noted in the control group (P = 0.004). On admission, the median C-reactive protein value was significantly higher in the study group (202.6 mg/L versus 83 mg/L in the control group; P = 0.001). Eleven patients with PVL-positive infection had local extension of the infection by magnetic resonance imaging and 7 patients had severe deep-seated infectious complications by computed tomography. By contrast only 1 patient in the control group presented with bone abscess without extension and none had deep-seated infection (P < 0.001). The median length of hospitalization was 45.5 days in the study group versus 13 days in the control group (P < 0.001). The median duration of intravenous antibacterial chemotherapy was 48 days versus 11.3 days in the control group (P < 0.001). Ten patients (71%) of the study group required surgical procedures with a mean of 3 procedures (range, 1–5) whereas 3 patients (17%) of the control group required 1 surgical drainage each (P = 0.002). All the patients survived, but only 2 patients of the study group were free of long-term complications, whereas there were no long-term complications noted in the control group. Conclusion: PVL-positive S. aureus bone and joint infection is severe and requires prolonged treatment. Local complications are more frequent and often need repeated surgical drainage.

Panton–Valentine leukocidin is expressed at toxic levels in human skin abscesses

Pus samples were prospectively collected from patients with Staphylococcus aureus skin infections and tested for Panton-Valentine leukocidin (PVL). PVL was detected at concentrations that were toxic for rabbit skin in all specimens from patients infected with strains harbouring PVL genes.

Infections ostéoarticulaires à staphylocoques dorés sécréteurs de la leucocidine de Panton-Valentine

Panton-Valentine Leucocidin (PVL) is associated in the USA with community-acquired meticillin resistant strains of Staphylococcus aureus (CA-MRSA). Bone and joint infection due to such strains appears to be more severe, necessiting longer antibiotic course and various surgical procedure. Our study of 14 PVL positive bone and joint infection, performed in France where PVL is rarely (2/14) associated with meticillin resistance, demonstrates that severity is linked with PVL secretion more than with resistance. Considering PVL associated bone and joint infections as a toxin-mediated disease, prompt diagnosis is needed in order to start specific therapeutic procedures. PVL mediated infection could be evoked in front of severe acute osteomyelitis or arthritis, with radiological abnormalities present in the first days of evolution and with pejorative evolution despite antibiotic treatment. Evolution toward multifocal osteomyelitis and/or multiple abscesses seems to be a major characteristic of such infection. Therapeutic approach should use an association of parenteral antibiotics with at least one molecule active against protein synthesis like Clindamycin, associated with betalactams or Vancomycin in area of high incidence of CA-MRSA. Surgical procedure should be considered whenever focal abscesses of bones or adjacent tissue is detected and should be repeated in most cases.

Gait parameters database for young children: The influences of age and walking speed

BACKGROUND Reference databases are mandatory in orthopaedics because they enable the detection of gait abnormalities in patients. Such databases rarely include data on children under seven years of age. In young children, gait is principally influenced by age and walking speed. The influence of the age-speed interaction has not been well established. Therefore, the objective of the present study is to propose normative values for biomechanical gait parameters in children taking into account age, walking speed, and the age-speed interaction. METHODS Gait analyses were performed on 106 healthy children over a large age range (between one and seven years of age) during gait trials at a self-selected speed. From these gait cycles, biomechanical parameters, such as the joint angles and joint power of the lower limbs, were computed. Specific peak values and the times of occurrence of each biomechanical gait parameter were identified. Linear regressions are proposed for studying the influence of age, walking speed and the age-speed interaction. FINDINGS Most of the regressions achieved good accuracy in fitting the curve peaks and times of occurrence, and the normal reference targets of biomechanical parameters could be deduced from these regressions. The biomechanical gait parameters of a pathological case were plotted against the normal reference targets to illustrate the relevance of the proposed targeting method. INTERPRETATION The normal reference targets for biomechanical gait parameters based on age-speed regressions in a large database might help clinicians detect gait abnormalities in children from one to seven years of age.

Pseudarthrose congénitale de l’avant-bras associée à la neurofibromatose: À propos d’un cas et revue de la littérature

We report a case of congenital pseudarthrosis of the forearm associated with neurofibromatosis type 1 which was treated by free vascularized periosteal flap transplant and repeated bone grafting. The young female patient recovered good hand and forearm function. A review of the literature revealed the rare occurrence of this disease (approximately 100 cases reported to date), which probably explains the wide variety of surgical proposals.Resume Les auteurs rapportent un cas de pseudarthrose congenitale de l’avant-bras, associee a la neurofibromatose de type 1, qui a ete traite par un lambeau libre de perioste et des greffes osseuses a repetition. La jeune patiente a aujourd’hui une bonne fonction de la main et de l’avant-bras. Une revue de la litterature montre la rarete de cette affection (environ 100 cas rapportes a ce jour) expliquant la diversite des attitudes therapeutiques.

Intérêt de la toxine botulique pour les suites opératoires en chirurgie des membres chez l'enfant infirme moteur cérébral

Resume La spasticite et les spasmes musculaires peuvent etre a l’origine de douleurs chez l’enfant infirme moteur cerebral (IMC). La realisation d’actes chirurgicaux orthopediques est souvent necessaire chez ces patients et les phenomenes douloureux postoperatoires peuvent etre aggraves par la spasticite, alors qu’elle est elle-meme augmentee par l’epine irritative que representent les douleurs postchirurgicales. De meme, ces symptomes peuvent etre aggraves par les mouvements anormaux, l’immobilisation plâtree ou encore l’anxiete des patients. Le traitement de la spasticite est une necessite apres une chirurgie orthopedique chez les enfants IMC. Une etude randomisee a montre recemment l’interet de l’utilisation de la toxine botulique (toxine botulique) avant une chirurgie tendineuse chez l’IMC. Le but de cette etude etait d’evaluer les benefices en termes de confort et de douleur, obtenus par l’utilisation de la toxine botulique dans le cadre d’une chirurgie osseuse realisee chez des enfants IMC tetraplegiques spastiques. Deux groupes de 9 patients IMC tetraplegiques spastiques ayant subi une intervention chirurgicale orthopedique pour chirurgie osseuse ou chirurgie multi-site ont ete compares lors d’une etude retrospective : un des groupes recevait de la toxine botulique avant l’intervention. Tous les patients ont ete immobilises en postoperatoire pour une duree moyenne de 6 semaines. Les principaux criteres etudies ont ete : l’efficacite et les effets secondaires de la toxine botulique, la duree de l’hospitalisation, de la douleur et du traitement antalgique de niveau III (morphine), la qualite du sommeil, enfin la survenue de lesions cutanees lors de l’immobilisation. Aucune difference significative ne separait les deux groupes de patients (en dehors du traitement par toxine botulique). L’efficacite et l’innocuite clinique de la toxine botulique ont pu etre confirmees. Aucune difference significative n’a ete retrouvee concernant la duree d’hospitalisation : 7,33 jours (e.t ± 1,5) contre 7,88 jours (e.t ± 1,7) ainsi que pour le duree d’utilisation d’antalgiques de niveau III : 4,33 jours (e.t ± 1,9) pour 4,16 jours (e.t ± 2,5). Cependant la duree des symptomes douloureux a diminue significativement de 6,87 jours (e.t ± 2,9) a 2,22 jours (e.t ± 1,7) et la qualite du sommeil des patients a ete significativement amelioree et les lesions cutanees sous immobilisation ont pu etre prevenues pour le second groupe. Ce travail ne permet pas de confirmer que l’utilisation de toxine botulique diminue la consommation d’antalgiques chez ces patients. Cependant nos resultats sont en faveur d’une diminution de la duree des phenomenes douloureux postoperatoires et d’une amelioration du confort des enfants IMC spastiques operes lorsqu’une administration de toxine botulique a ete realisee en preoperatoire. Cette etude suggere qu’un benefice peut etre attendu de l’administration de toxine botulique en preoperatoire et les auteurs conseillent d’etendre ses indications a toute chirurgie orthopedique realisee chez un patient spastique.

Fracture transversale du sacrum chez l’enfant: À propos d’un cas avec complication neurologique et revue de la littérature

Resume Les fractures transversales du sacrum sont exceptionnelles chez l’enfant. Les auteurs rapportent le cas d’une patiente âgee de 10 ans presentant une fracture isolee du sacrum en flexion au niveau de la zone III de Denis (type transversal en « U ») a l’etage S1-S2. La patiente presentait des signes neurologiques sensitifs perineaux et moteurs sphincteriens lors de l’examen initial. Le traitement a consiste en une laminectomie et une resection osseuse a visee de decompression, en raison des lesions neurologiques. Un traitement orthopedique de la lesion osseuse a permis la consolidation avec un excellent resultat. Avec un recul de trois ans, l’evolution du deficit neurologique est completement favorable. La revue de la litterature ne retrouve que 8 cas rapportes de cette lesion avant l’âge de 18 ans. Les elements du diagnostic sont similaires a ceux chez l’adulte, mais le caractere exceptionnel de la lesion chez l’enfant peut etre a l’origine d’un retard de diagnostic et de traitement. L’attitude therapeutique reste controversee dans la litterature chez l’adulte et pour le moment non codifiee chez l’enfant. Les auteurs preconisent le traitement chirurgical des complications neurologiques et le traitement orthopedique des lesions osseuses stables.

Is there a predominant influence between heel height, upper height and sole stiffness on young children gait dynamics?

Specific geometric and mechanical properties are required for running shoes to prevent musculo-skeletal system injuries (Paul et al. 1978). Likewise, specific shoes are necessary during young children growth. Some reviews about children shoes proposed several recommendations, but predominantly based on interpretations of barefoot locomotion (Walther et al. 2008; Wegener et al. 2011). One study compared barefoot and shod gait (Kristen et al. 1998) on young children, with various sole geometries. The parameters observed were temporal distance parameters and ground reaction force, but there was no information about kinematics. However, the main changes on kinematic and dynamic gait patterns appear in the first years of independent walking (Samson et al. 2011). Moreover, Samson et al. (2012) revealed the speed of progression influence on shod gait. In order to provide recommendations to shoe designers, it is important to evaluate the influence of different shoe criteria on gait and to identify if one criterion is predominant, considering also age and speed of progression variation.

The spastic hip in children and adolescents

The hip is the joint most exposed to orthopaedic complications in cerebral palsy (CP), which is the main cause of spasticity in paediatric patients. The initial immaturity of the hip allows the forces applied by the spastic and retracted muscles to displace the femoral head, eventually causing it to dislocate. The risk of hip dislocation increases with the severity and extent of CP, exceeding 70% in the most severe cases. Hip dislocation causes pain in up to 30% of cases, carries a risk of orthopaedic and cutaneous complications and hinders patient installation and nursing care. These adverse outcomes warrant routine screening, which has been proven effective in lessening the frequency and severity of hip displacement. Preventive techniques including physical therapy, orthoses and treatments to alleviate spasticity are strongly recommended in every case. The beneficial effects of treating spasticity, if needed via neurosurgical procedures, have been convincingly established. Orthopaedic surgery is required when prevention fails. Soft-tissue release is designed to correct the asymmetry in the forces applied by the muscles. Femoral osteotomy creates the possibility for spontaneous correction of secondary acetabular dysplasia. Progress has been made in standardising the use of multilevel surgery involving the soft tissues, femur and pelvis, which is often effective in correcting the morphological abnormalities and stabilising the joint. When hip pain or alterations are severe, hip resection or total hip arthroplasty are highly effective in alleviating the pain and improving patient comfort. The spastic hip is a complex condition in which currently available screening protocols and treatment strategies have been proven effective in benefitting patient outcomes.

Hip internal rotation in cerebral palsy: does femoral derotation osteotomy influence abductor insufficiency?

Inadequate hip abductor muscle strength in ambulatory cerebral palsy (CP) can be related to several factors of muscle weakness (i.e. motor control, muscle tissue modification, co-activation, spasticity, or lever arm dysfunction). Lever arm dysfunction seems to be the main factor that surgery could improve with a femoral derotation osteotomy (FDO), but this assumption has not been objectively confirmed until now. It had been assumed that the hip internal rotation (HIR) was a sign of lever arm dysfunction at the hip and the effect of HIR on the efficiency of gluteus medius is well known. Toddlers experiment daily with this condition when walking, coping with their physiological anteversion. Individuals with CP might likewise cope with hip abductor moment insufficiency while using the same functional adaptation (if we leave aside other causes of HIR in CP). The study presented by Boyer et al. is the first to question the results of FDO on hip abductor moment in a clinical series. In theory, FDO should solve the lever arm dysfunction, but it is not expected to correct the position of the femur’s proximal extremity in CP. FDO should result only in external rotation of the distal part of the femur, bringing the knee plane of motion in the sagittal plane. Spasticity and/or contractures could play a role in maintaining the proximal femoral extremity in its initial position. Therefore, FDO should not alter the hip abductor moment. Thus, its efficacy in improving the lever arm dysfunction could be limited: (1) to cases with very marked femoral anteversion, when the HIR range cannot compensate the effect of initial femoral anteversion; and (2) to individuals who have anatomical limitation to hip rotation such as capsule contracture or muscle contracture/spasticity. In their study, Boyer et al. assessed the hip abductor moment and hip abductor moment arm in ambulatory CP. They found a slight improvement of hip abductor moment, but this was not maintained at 1-year follow-up. As the patients underwent several months of rehabilitation after single-event multilevel surgery, isometric hip abductor strength was hopefully conserved so unloading limb prior to implant removal would not be a convincing explanation. Moreover, if the anatomical effect of FDO is confirmed at short-term (hip rotation, anteversion, and % change), the position of the proximal femoral extremity related to pelvis would have been also an important parameter to investigate. It is not obvious to account for the variations of hip abductor moment observed between shortand mid-term while at the same time hip rotation deteriorated, anteversion increased, and abduction moment arm did not change. This could be related to improvement in isometric hip abductor strength, but it is unlikely that the improvement of hip abductor moment results only by eventual improvement of the moment arm. More likely, the overall effect of single-event multilevel surgery plays a similar part as the intensive rehabilitation following surgery. Muscle strength also improved with time in the study. Additional factors may have contributed to this, such as daily life activities, rehabilitation, and perhaps puberty. Finally, the amount of femoral anteversion could play a part. In summary, the study of Boyer et al. brings new information about the evolution of hip abductor moment after FDO. Yet it seems that the improvement cannot be exclusviely attributed to FDO. Other surgical procedures should be tested to manage HIR and functional hip abductor insufficiency in further studies. Nevertheless, the complexity of single-event multilevel surgery procedure will continue to induce confounding factors when interpreting the results.