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Background: Management of moderately displaced slipped capital femoral epiphysis (SCFE) is debated, mostly because of the risks related to open reduction on one hand, and subsequent evolution toward femoroacetabular impingement (FAI) on the other., Method: All SCFE cases treated with in situ fixation (ISF) and a minimum of ten years of follow-up beyond skeletal maturity were analysed in a retrospective multicentre study. Coxometry parameters were measured. Long-term results of ISF were meanwhile analysed at our Institution., Results: A total of 222 patients were included. Patient reported outcome measurements were related to the severity of the initial slip. It suggested a 35.5° threshold for slip angle beyond which FAI was more frequent. Only slight remodelling at the head-neck junction is to be expected., Conclusion: Based on these findings, it seems reasonable to perform ISF only in SCFE with a slip angle below 35°.

Background: In situ pinning of slipped capital femoral epiphysis (SCFE) results in various degrees of deformity of the femoral head-neck junction. Repetitive trauma from cam-type femoroacetabular impingement (FAI) can lead to labral tears and injury to the articular cartilage causing loss of function. Arthroscopic osteoplasty is an alternative to open procedure and to Southwick/Imhäuser-type osteotomies in symptomatic selected cases., Surgical Technique: The amount of bone to be resected has to be carefully planned pre-operatively. Only gentle traction is applied on a well-padded perineal support. A spherical burr is used to gradually resect the prominence. Intra-operative fluoroscopy is very useful when checking adequate reshaping of the head-neck junction is obtained., Results: Arthroscopy often reveals acetabular cartilage lesions, labrum hyperhemia and fraying which rarely require repair. Arthroscopic osteoplasty provides satisfactory pain relief and, to a lesser extent, restores hip internal rotation., Conclusion: Arthroscopic osteoplasty is more technically and time-demanding in post SCFE than idiopathic FAI. It requires strong arthroscopic skills and experience in hip arthroscopy. It stands as a reasonable alternative to open procedure or flexion osteotomies in symptomatic FAI post mild to moderate SCFE. It provides pain relief and to a lesser extent restores internal rotation of the hip.

Introduction: The classic pathophysiology of acute osteomyelitis in children described by Trueta has a metaphyseal infection as the starting point. This hypothesis was recently brought into question by Labbé's study, which suggested a periosteal origin. Thus, we wanted to study this disease's pathophysiology through early MRI examinations and to look for prognostic factors based on abnormal findings., Material and Methods: This was a prospective, multicentre study that included cases of long bone osteomyelitis in children who underwent an MRI examination within 7days of the start of symptoms and within 24hours of the initiation of antibiotic therapy. We also collected clinical, laboratory and treatment-related data., Results: Twenty patients were included, including one with a bifocal condition. The lower limb was involved in most cases (19/21). Staphylococcus aureus was found most frequently. Metaphyseal involvement was present in all cases. No isolated periosteal involvement was found in any of the cases. No prognostic factors were identified based on the various abnormal findings on MRI., Conclusion: Our study supports the metaphyseal origin of acute osteomyelitis in children., Level of Evidence: II., (Copyright © 2016. Published by Elsevier Masson SAS.)

Introduction: Tibial intercondylar eminence fracture rarely occurs in childhood. Its treatment requires anatomic reduction to provide knee stability and a rigid fixation to minimize postoperative immobilization time., Hypothesis: Arthroscopy combined with fluoroscopy with intra-epiphyseal ASNIS screw fixation can meet the requirements of this treatment., Material and Methods: The series comprised 24 patients (mean age: 11 years) with Meyers and McKeever type II tibial intercondylar eminence fractures (n=15) or type III (n=9), operated on between 2011 and 2013. Fixation with 4-mm ASNIS screws was placed arthroscopically. The demographic data, associated lesions, radiological union, stability, functional result, and the Lysholm score were evaluated., Results: With a mean follow-up of 2 years, the mean Lysholm score was 99.3 for type II and 98.6 for type III fractures. At the 6th postoperative week, range of motion in the operated knees was identical to the healthy knees. At the 12th postoperative week, there was no sign of anterior laxity. Twelve cases included meniscal entrapment, but no significant difference was observed in the functional results., Discussion, Conclusion: ASNIS screw fixation under arthroscopy can be successfully applied in the treatment of types II and III tibial intercondylar eminence fractures in children. This technique provides excellent stability, allows early weigh-tbearing, and preserves function of the knee and its growth., Level of Evidence: IV, retrospective study., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Introduction: Intramedullary limb lengthening systems include mechanical systems (the Albizzia nail and the ISKD nail) as well as motorized systems with the Fitbone(®) (Wittenstein, Igersheim, Germany) and the Precice(®) (Ellipse Technologies, Irvine, CA, USA) nails. We hypothesized that limb lengthening using the Fitbone(®) nail was reliable, reproducible, and comfortable for the patient., Patients and Methods: Between 2010 and 2013, a prospective single-center, single-operator (FA) study was conducted on patients who had undergone limb lengthening using the Fitbone(®) nail. The inclusion criteria were length discrepancy of the limbs equal to or greater than 25 mm or a short stature. The exclusion criteria were indications for cosmetic reasons and/or growth plates that were still open. The lengthening parameters were assessed postoperatively and at the last follow-up. Lengthening was considered achieved when the lengthening objective did not differ by more than 5 mm. All complications were noted. A statistical analysis was performed., Results: Twenty-six Fitbone(®) nails were implanted in 23 patients, in the femur in 15 cases and the tibia in 11 cases. The patients' mean age was 22.5 years (range: 15-53 years) and the mean follow-up was 3.4 years (range: 2-5.3 years). The limb lengthening targeted was obtained in 23 cases (88%) and the mean lengthening was 45.3±18 mm (range: 20-80 mm). The mean time to healing was 277±167 days (range: 86-638 days). The mean healing index was 73±57 days/cm for the femurs and 83.5±65 days/cm for the tibias. The mean complication rate was 15.4%., Discussion: This study emphasizes the good short-term results of this motorized intramedullary lengthening system. An evaluation over the longer term and with a higher number of patients remains necessary., Level of Evidence: IV: uncontrolled, prospective, continuous study., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: Whole-genome sequencing studies have recently shown that osteosarcomas (OSs) display high rates of structural variation, i.e. they contain many somatic mutations and copy number alterations. TP53 and RB1 show recurrent somatic alterations in concordant studies, suggesting that they could be key players in bone oncogenesis., Patients and Methods: we carried out whole-genome sequencing of DNA from seven high-grade OS samples matched with normal tissue from the same patients., Results: We confirmed the presence of genetic alterations of the TP53 (including novel unreported mutations) and RB1 genes. Most interestingly, we identified a total of 84 point mutations and 4 deletions related to 82 different genes in OS samples, of which only 15 have been previously reported. Interestingly, the number of mutated genes (ranging from 4 to 8) was lower in TP53mut cases compared with TP53wt cases (ranging from 14 to 45). This was also true for the mutated RB1 case. We also observed that a dedifferentiated OS harboring MDM2 amplification did not carry any other mutations., Conclusion: This study suggests that bone oncogenesis driven by TP53 or RB1 mutations occurs on a background of relative genetic stability and that the dedifferentiated OS subtype represents a clinico-pathological entity with distinct oncogenic mechanisms and thus requires different therapeutic management., (© The Author 2016. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: Cartilaginous tibial eminence fracture (CTEF) is a new pattern of ACL rupture in children under the age of nine. MRI signs have been recently reported, but no series gave information about outcomes. It was hypothesized that primary treatment gave better results than delayed management due to frequent misdiagnosis., Method: This retrospective study focused on 15 patients, managed acutely (n = 7) or delayed (n = 8). The patients' median age at the time of initial injury was 6.5 years (range 5-9). Lysholm, IKDC 2000 subjective scores, and the measurement of the residual laxity by a side-to-side difference with a KT-1000 junior arthrometer were used at the time of revision., Results: After a mean follow-up of 9.8 years (range 1-18.5), the mean Lysholm and IKDC subjective scores were, respectively, 97.7 ± 2.6 and 97 ± 3.4. The median residual laxity was 2 mm (range 0-4). Non-operative treatment lead to 2 failures: intermeniscal ligament entrapment and combined avulsion fracture at the femoral site. Suture fixation of the avulsed fragment allows regularly good results when performed acutely or even 4 years after the injury. The hypothesis that primary treatment gives better result than delayed treatment tends to be wrong as 2 failures were reported in each group. An ACL reconstruction was performed in 3 out of the 4 treatment failures. Progressive resorption of the avulsed fragment was noticed in 3 of the 4 failures suggesting an associated ACL resorption., Conclusion: CTEF has a good prognosis even after misdiagnosis and treatment at the time of non-union; this could be due to low-energy mechanism of injury and low rate of associated lesion. Orthopaedic treatment for acute minimally displaced fractures is only indicated under strict MRI control, and suture fixation is the recommended strategy in other situations. Conservative management of non-union could expose to ACL involution and cannot be recommended., Level of Evidence: Retrospective case series, Level IV.

Purpose: This study presents the results of a prospective consecutive cohort of patients with Legg-Calvé-Perthes disease (LCPD) operated with triple osteotomy of the pelvis (TOP) between 1989 and 2005. We attempted to determine whether the results of TOP remain stable with time and consequently lower the risk of subsequent osteoarthritis. The primary study aims were to determine the maintenance of head coverage and joint congruity, and functional outcomes of this surgery., Methods: Forty-five patients with a mean follow-up of 15.2 years (range eight to 24) were included., Results: At latest follow-up, two patients were lost to follow-up, and two required a surgical reoperation. Cumulative maintenance of head coverage and joint congruity rate for all TOP was 84.6 % (95 % CI: 82.3-90.6 %) at 15 years. Factors significantly associated with poor long-term results were the age at diagnosis and Greene index., Conclusion: TOP in LCPD provides satisfactory and reproducible long-term clinical results.

Background: A control study was designed to investigate circulating Ghrelin levels in adolescent girls with adolescent idiopathic scoliosis (AIS) and controls. Eating behavioral disorders, endocrine disorders, abnormal growth pattern and osteopenia have been well documented in AIS. Ghrelin is an orexigenic hormone produced by the stomach which reflects body weight changes and stimulates growth hormone secretion. Recently, it has been shown to be associated with bone metabolism and eating behavior. However, the circulating levels of ghrelin have never been evaluated in AIS patients., Methods: Forty nine AIS girls and 15 controls were included. Anthropometric parameters and fasting circulating total ghrelin were measured. Curve severity was evaluated in AIS girls. The relationships between ghrelin and age, body weight, height, body mass index (BMI), BMI Z-score and corrected anthropometric parameters were analyzed in AIS girls and controls., Results: There was no significant difference in body weight, height, BMI or BMI Z-score between AIS and controls. Serum ghrelin level was 1.8 fold higher in AIS girls than in controls. Elevation of ghrelin levels remained significant when corrected BMI or corrected BMI Z-score were considered. Unlike in controls, positive correlations were found between ghrelin and age in AIS girls with a gradual increase of circulating ghrelin with age., Conclusions: We have observed significantly higher circulating ghrelin levels in AIS than in controls with a positive correlation with age. This pilot-study suggests that ghrelin signaling might play a role in the initiation or development of AIS. Further studies are needed to validate theses results.

Limping in children. Limping is a frequent referral in children. Several types of limping have been described. The antalgic gait and Trendelenburg gait are the classics. The multiplicity of aetiologies and a clinical examination often difficult in small children complicate the etiological diagnosis. A thorough history and clinical examination are essential to guide further investigations. The aetiology and diagnostic tools are discussed in this article., Competing Interests: J. Sales de Gauzy déclare des interventions ponctuelles pour Implanet et avoir été prise en charge à l’occasion de déplacements pour congrès par Medtronic. F. Accadbled et A. Ibnoulkhatib déclarent n’avoir aucun lien d’intérêts.

Background: Surgical treatment of early-onset scoliosis has greatly developed in recent years. Early-onset scoliosis covers a variety of etiologies (idiopathic, neurologic, dystrophic, malformative, etc.) with onset before the age of 5 years. Progression and severity threaten respiratory development and may result in respiratory failure in adulthood. Many surgical techniques have been developed in recent years, aiming to protect spinal and thoracic development., Material and Methods: Present techniques are based on one of two main principles. The first consists in posterior distraction of the spine in its concavity (single growing rod, or vertical expandable prosthetic titanium rib [VEPTR]), or on either side (dual rod); this requires iterative surgery, for lengthening, unless motorized using energy provided by a magnetic system. The second option is to use spinal growth force to lengthen the assembly; these techniques (Luque Trolley, Shilla), using a sliding assembly, are known as growth guidance., Results: These techniques are effective in controlling early scoliotic deformity, and to some extent restore spinal growth. However, they show a high rate of complications: infection, rod breakage, spinal fixation pull out and, above all, progressive spinal stiffness, reducing long-term efficacy. Respiratory gain is harder to assess, as thoracic expansion does not systematically improve respiratory function, particularly due to impaired compliance of the thoracic cage., (Copyright © 2015. Published by Elsevier Masson SAS.)

Lower-limb bone metastases are uncommon in low-grade endometrial carcinoma, and are mostly located on the axial skeleton. Here, we present a rare case of bilateral femur metastases in low-grade endometrial carcinoma and performed a review of the current literature.

Purpose: To evaluate in children the agreement between femoral and tibial torsion measurements obtained with low-dose biplanar radiography (LDBR) and CT, and to study dose reduction ratio between these two techniques both in vitro and in vivo., Materials and Methods: Thirty children with lower limb torsion abnormalities were included in a prospective study. Biplanar radiographs and CTs were performed for measurements of lower limb torsion on each patient. Values were compared using Bland-Altman plots. Interreader and intrareader agreements were evaluated by intraclass correlation coefficients. Comparative dosimetric study was performed using an ionization chamber in a tissue-equivalent phantom, and with thermoluminescent dosimeters in 5 patients., Results: Average differences between CT and LDBR measurements were -0.1° ±1.1 for femoral torsion and -0.7° ±1.4 for tibial torsion. Interreader agreement for LDBR measurements was very good for both femoral torsion (FT) (0.81) and tibial torsion (TT) (0.87). Intrareader agreement was excellent for FT (0.97) and TT (0.89). The ratio between CT scan dose and LDBR dose was 22 in vitro (absorbed dose) and 32 in vivo (skin dose)., Conclusion: Lower limb torsion measurements obtained with LDBR are comparable to CT measurements in children and adolescents, with a considerably reduced radiation dose., Key Points: • LDBR and CT lower-limb torsion measurements are comparable in children and adolescents. • LDBR considerably reduced radiation dose necessary for lower-limb torsion measurements. • LDBR can be used for evaluation of lower limb-torsion in orthopaediatric patients.

Introduction: Slipped capital femoral epiphysis (SCFE) can lead to hip impingement, more or less rapidly depending on initial slippage severity and on surgical technique. Various surgical options are applicable, including in situ fixation (ISF). The aim of the present study was to look for long-term signs of radiological impingement in hips treated for SCFE by IFS, in order to identify a slip threshold beyond which impingement more regularly appears., Material and Methods: A multicenter retrospective study assessed the clinical and radiological evolution of patients operated on by ISF for SCFE, with a minimum 10 year's follow-up. Coxometric analysis of postoperative and last follow-up radiographs was performed. Functional outcome was assessed on Oxford hip score and radiographic osteoarthritis on the Tönnis classification. Alpha angle was measured on lateral views to highlight hip impingement., Results: Two hundred and twenty-two hips were included, with a mean 11.2 years' follow-up. Mean age at diagnosis was 12.8 years. Mean preoperative Southwick angle was 38.8°, with 43% of hips at stage I, 42% at stage II and 15% at stage III. At latest follow-up, mean Oxford score was 14.86, with 88% of hips rated Tönnis 0 or I. Only 15 cases of impingement were diagnosed. There seemed to be a non-significant trend for hip impingement in SCFE exceeding 35°., Conclusion: ISF led to hip impingement in moderate to severe initial epiphyseal displacement. However, in smaller displacement, the consequences were milder, with perfectly satisfactory function scores and no clinical or radiological evidence of impingement. The threshold seemed to be around 35° slippage, beyond which other surgical options than ISF should be considered. Thus, it seems reasonable to propose isolated ISF in SCFE<35° and to treat symptomatic impingement by surgery in stage II slips., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Rotational femoral osteotomies for excessive femoral antetorsion may be considered only for symptomatic adolescents. Our main objective was to describe our femoral osteotomy technique. Preoperative planning was performed clinically and with the EOS imaging system. Percutaneous osteotomy was performed on distal femoral metaphysis under radioscopic control. Fixation was achieved with an antegrade locking nail. Rotation was checked precisely using a specially designed protractor before distal locking. We carried out a prospective pilot study between 2009 and 2010 on six patients (nine procedures). All the patients included presented a symptomatic femoral antetorsion greater than 20°. Clinical parameters including range of hip mobility and femoral antetorsion were measured every 2 months during the first 6 months, and then every year until skeletal maturation was reached. We obtained orthoroentgenograms using the same technique at each follow-up and torsional analysis by EOS 3D Imaging at 6 months. The average correction of the femoral antetorsion was 19.0 ± 4.0° (range, 13-25°). The average time of union was 3 ± 1.2 months (range, 2-6 months). Patients returned to full weight bearing at an average of 2.6 ± 0.4 months (range, 2-4 months). One patient experienced an early secondary displacement in varus for which a reoperation was required. We believe that this technique can accurately achieve derotational femoral osteotomies. A study is ongoing to evaluate the clinical results of this technique including mechanical and cosmetic advantages.

Objectives: The objective of this study was to investigate cases of femoroacetabular impingement (FAI) and analyze the risk factors for a painful hip at skeletal maturity after Perthes disease. We hypothesized that FAI occurs as a sequela of Perthes disease and that coxa plana and triple osteotomy of the pelvis (TOP) may be risk factors., Methods: Ninety-five hips were included from 1981 to 2011, 56 of which were operated on with TOP (53) or shelf acetabuloplasty (3). The results were evaluated at a mean 13years of follow-up (range, 2-23years) with Oxford score and hip radiograph analysis including the Stulberg grade, coxometry, and presence of a femoral bump. FAI was characterized by positional hip pain with preserved joint space and aspherical/nonspherical femoral head., Results: The Oxford score was optimal (12) in 79 hips (75%) and 20 or above in nine hips (9.5%). Seventeen hips were rated Stulberg I (18%), 36 Stulberg II (38%), 27 Stulberg III (28%), and 15 Stulberg IV or V (16%). The average acetabular angle was 10° (range, -4 to 25), VCE 41.5° (range, 18-80), and VCA 38.5° (range, 13-70). A femoral bump was noted in 31 hips (33%). Five cases of FAI were managed operatively with at least pain relief. Hip pain at the latest follow-up correlated with coxa plana (P=0.0003) and femoral bump (P=0.007). No significant correlation was found with a history of hip surgery or coxometry parameters., Conclusion: Perthes hips bear risk for later FAI. Risk factors include coxa plana and femoral bump. In case of TOP, it is advocated to avoid excessive tilt, which may cause FAI., Level of Evidence: IV., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Unlabelled: The Universal Clamp (UC) equipped with a soft sublaminar band is a relatively new thoracic anchor that can be used in hybrid constructs. A dedicated reduction tool that applies traction to the sublaminar band permits gentle translation of the thoracic curve to the pre-contoured fusion rods, which have been previously anchored distally by pedicle screws and proximally by hooks in a claw configuration., Methods: A literature review concerning the use of UC in adolescent idiopathic Scoliosis was performed., Results: The results confirm the efficacy with the UC hybrid constructs, the good correction (71-66%) of the main thoracic curve and low loss of correction at 2-year follow-up (3-4%). The thoracic curve correction achieved and maintained in the AIS patients appears to be substantially higher than that reported for all hook and hook hybrid techniques. Regardless of the deformity correcting method employed with all-screw constructs, the Cobb angle correction achieved is equivalent to that achieved with UC hybrid devices. Among the present AIS patients who had normal values of thoracic kyphosis pre-operatively, there was almost no change in average thoracic kyphosis at the latest follow-up. However, among the patients with low pre-operative values of T5-T12 kyphosis, the average T5-T12 kyphosis improved., Conclusion: Hybrid construct with UC is safe, with reduced operative time and blood loss. While achieving deformity correction in the coronal and axial planes equivalent to the best-reported results of all screw or previous hybrid constructs, the UC hybrid technique appears to provide superior correction in the sagittal plane. The excellent outcome is maintained at the 2-year follow-up.

Slipped capital femoral epiphysis (SFCE) may lead to femoro acetabular impingement and long-term function impairment, depending on initial displacement and treatment. There are several therapeutic options which include in situ fixation (ISF). The objective of this study was to evaluate long-term functional and radiographic outcomes of patients with SFCE treated with ISF. We conducted a single-center, retrospective study evaluating the clinical and radiographic outcomes of SCFE in situ fixation with a mean follow-up of 26 years (10-47). Analysis of preoperative and last follow up radiographs was performed. The functional status of the hip was evaluated according to the Oxford hip score-12 and the radiographic osteoarthritis stage was rated according to Tönnis classification. Signs of femoro acetabular impingement were sought. Ten patients (11 hips) were included. The average initial slip was 33.5° (10-62). At final follow up, the average Oxford hip score was 19.3 (12-37), it was good for groups who had a small initial slip (16.7) or moderate (17) and fair for the severe group (27). Average Tönnis grade was 1.3 (0-3). The average alpha angle was 65.3° (50-80°). Femoro acetabular impingement was likely in 100% of patients with severe slip, in 50% of patients with moderate slip and in 33% of patients with a slight slip. In situ fixation generated poor functional results, substantial hip osteoarthritis and potential femoro acetabular impingement in moderate to severe SCFE's. However, in cases with minor displacement, functional and radiographic results are satisfactory. The cut off seems to be around 30° slip angle, above which other treatment options should be considered.

Background: Surgical strategy for Ewing sarcoma (ES) of the pelvis relies on Enneking classification. In adults, in case the acetabulum is involved, excision of the entire acetabulum is needed and often leads to loss of function. In children, the surgeon may adopt a strategy, such as in metaphyseal tumors of long bones where an unaffected growth plate allows a transepiphyseal resection, therefore sparing the joint., Methods: We present a "triradiate cartilage strategy" for the excision of ES of the pubic component of the acetabulum, which allows a wide resection while preserving most of the socket. The approach is ilioinguinal. Osteotomies of the iliopubic and ischio pubicrami are performed, followed by hip arthrotomy and anterior dislocation. Transacetabular resection is achieved using osteotomes, under image intensifier guidance, with no further reconstruction. Cases are presented for 2 boys aged 6.5 and 9.5 years, treated with chemotherapy and transacetabular resection., Results: Resections were all rated R0. Patient #1 remained asymptomatic, including during sport activities, and had normal hip range of motion at 12-year follow-up. Radiograph demonstrated mild protrusio acetabuli. Patient #2 had no complain at 3-year follow-up with normal hip range of motion, although he presented with an equinus gait. Radiographs demonstrated a well-covered femoral head without medial shift., Conclusions: A "growth plate-based" surgical strategy can be adapted to malignant pelvic tumors in skeletally immature children. This technique leaves intact the ilio ischiatic component of the triradiate cartilage, which, according to Ponseti, contributes the most to the growth of the acetabulum. Joint sparing improves the functional result and decreases the risk of complication., Level of Evidence: IV.

Study Design: Multicenter retrospective study of 54 children., Objective: To describe the complication rate of the French vertical expandable prosthetic titanium rib (VEPTR) series involving patients treated between August 2005 and January 2012., Summary of Background Data: Congenital chest wall and spine deformities in children are complex entities. Most of the affected patients have severe scoliosis often associated with a thoracic deformity. Orthopedic treatment is generally ineffective, and surgical treatment is very challenging. These patients are good candidates for VEPTR expansion thoracoplasty. The aim of this study was to evaluate the potential complications of VEPTR surgery., Methods: Of the 58 case files, 54 were available for analysis. The series involved 33 girls and 21 boys with a mean age of 7 years (range, 20 mo-14 yr and 2 mo) at primary VEPTR surgery. During the follow-up period, several complications occurred., Results: Mean follow-up was 22.5 months (range, 6-64 mo). In total, 184 procedures were performed, including 56 VEPTR implantations, 98 expansions, and 30 nonscheduled procedures for different types of complications: mechanical complications (i.e., fracture, device migration), device-related and infectious complications, neurological disorders, spine statics disturbances. Altogether, there were 74 complications in 54 patients: a complication rate of 137% per patient and 40% per surgery. Comparison of the complications in this series with those reported in the literature led the authors to suggest solutions that should help decrease their incidence., Conclusion: The complication rate is consistent with that reported in the literature. Correct determination of the levels to be instrumented, preoperative improvement of nutritional status, and better evaluation of the preoperative and postoperative respiratory function are important factors in minimizing the potential complications of a technique that is used in weak patients with complex deformities.

Intraoperative spinal cord monitoring consists in a subcontinuous evaluation of spinal cord sensory-motor functions and allows the reduction the incidence of neurological complications resulting from spinal surgery. A combination of techniques is used: somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), neurogenic motor evoked potentials (NMEP), D waves, and pedicular screw testing. In absence of intraoperative neurophysiological testing, the intraoperative wake-up test is a true form of monitoring even if its latency long and its precision variable. A 2011 survey of 117 French spinal surgeons showed that only 36% had neurophysiological monitoring available (public healthcare facilities, 42%; private facilities, 27%). Monitoring can be performed by a neurophysiologist in the operating room, remotely using a network, or directly by the surgeon. Intraoperative alerts allow real-time diagnosis of impending neurological injury. Use of spinal electrodes, moved along the medullary canal, can determine the lesion level (NMEP, D waves). The response to a monitoring alert should take into account the phase of the surgical intervention and does not systematically lead to interruption of the intervention. Multimodal intraoperative monitoring, in presence of a neurophysiologist, in collaboration with the anesthesiologist, is the most reliable technique available. However, no monitoring technique can predict a delayed-onset paraplegia that appears after the end of surgery. In cases of preexisting neurological deficit, monitoring contributes little. Monitoring of the L1-L4 spinal roots also shows low reliability. Therefore, monitoring has no indication in discal and degenerative surgery of the spinal surgery. However, testing pedicular screws can be useful. All in all, thoracic and thoracolumbar vertebral deviations, with normal preoperative neurological examination are currently the essential indication for spinal cord monitoring. Its absence in this indication is a lost opportunity for the patient. If neurophysiological means are not available, intraoperative wake-up test is a minimal obligation., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Bone reconstruction after surgical resection of bone malignancies in children remains a difficult challenge. Induced-membrane reconstruction as described by Masquelet et al. was originally reported in traumatic or septic bone defects and is now adapted to this field. We report here three cases of massive femoral graft resorption requiring surgical revision in two boys aged 3 and 6 years and a 9-year-old girl. Hypotheses include the long delay between the two stages, nature of the bone graft, high varus loads specific to this location, and lack of stability of the fixation. This technique has recently provided promising preliminary results when applied to the field of bone tumours. However, reconstruction of the femur seems to be specifically associated with a risk of graft resorption. Identification of the origin of this major complication is needed to amend the technique or its indications., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Spinal cord injuries are a well-known cause of neurological bladder and a well-known complication of high-velocity trauma. They can, however, be difficult to diagnose in young children, in whom the absence of initial neurological symptoms and normality of the radiological workup can be falsely reassuring. Management of associated injuries can further delay diagnosis. We present 2 cases of spinal cord injuries without radiological abnormality revealed by delayed bladder retention.

Monteggia fracture is an infrequent lesion, which associates ulna fracture and radial head dislocation. Equivalent Monteggia can occur by associated lesions such as olecranon fracture or radial neck or head fracture. We report an unusual case of Monteggia equivalent lesion associating a fracture of the proximal third of the ulnar shaft and a growth plate fracture Salter I of proximal-radial physis and divergent displacement due to a bottle-opener effect of the radial head over the capitellum during trauma. Surgical care consisted of intramedullary pinning of the radial head and fixation by a plate for ulna with a very good outcome., (© 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.)

Internal rotation contracture of the shoulder in brachial plexus birth palsy frequently leads to shoulder dysplasia. Six children underwent anterior arthroscopic release sparing the subscapularis. Clinical examination and MRI were performed preoperatively and repeated at the 5-year follow-up. MRI was carried out for assessment of glenohumeral dysplasia. Passive external rotation was improved by 63.3° without any limitation of active internal rotation. Active antepulsion/abduction was improved by 90°. Remodeling of the glenoid and improved coverage of the humeral head were observed in all cases. Shoulder arthroscopic release sparing the subscapularis seems to be an efficient procedure to restore external rotation without affecting active internal rotation.

Surgical management of tuberculosis is uncommon in children. We report a case of a 14-month-old boy with miliary tuberculosis and recurrent pneumothorax due to cavities in the left lung. This boy had no previous medical history and was referred to our hospital for a severe pneumonia. Initial chest radiograph showed bilateral miliary pattern. Direct microscopy of gastric lavage showed the presence of tubercle bacilli, providing definitive diagnosis. In spite of effective medication, his status rapidly worsened. A cardiac resuscitation was followed by intubation, and he required high-pressure ventilation for four weeks. He developed left pneumothorax, for which several drainages were performed. Computed tomography revealed a huge cavern system involving the entire lingula and surrounded by the left pneumothorax. Eventually, a massive enlargement of the initial cavity necessitated a thoracotomy and wedge resection.

Convective transports in the vertebral end plate (VEP) play a significant role in the homeostasis of the spine. A few studies hypothesised that the hydraulic resistance or effective permeability of the VEP could be dependant upon fluid-flow direction. Results were influenced by species, region of interest within the end plate and pathology. Some results were contradictory. We propose an analytical model based on steady-state Newtonian flows in capillary media to develop a phenomenological analysis of convective transport through the VEP. This dependence was established using a biquadratic analytical function involving porosities of subchondral bone, capillary bed and cartilage end plate. Discussion of results provided a theoretical justification for variable and/or contradictory experimental results concerning the amount of energy lost by fluid during its course through the end plate. Tissue porosities and, especially, those relative to the capillary bed could strongly influence the dependence of fluid energy loss on flow direction and could potentially modify tissue homeostasis related to the day and night cycle.

Calcaneonavicular coalition is a common source of pain and more or less severe flat and stiff foot in children. Classically, treatment consists in resecting the coalition using a dorsolateral approach. Good quality resection and interposition can prevent recurrence. The most common complications are infection, hematoma and neuroma. Arthroscopy offers a minimally invasive alternative, but the optimal approach remains undetermined. We describe a surgical technique with an approach based on the anterolateral process of the calcaneus, in three cases with 12 months' follow-up. Arthroscopic resection has certain advantages: recovery is quicker, and the esthetic result is better. For the instrumental portal, skin incision should be superficial, followed by blunt dissection of subcutaneous tissue to avoid superficial peroneal nerve injury. Although longer term follow-up is needed, arthroscopy seems to be an attractive minimally invasive technique in this kind of pathology., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Purpose: Among posterior surgical techniques for treating adolescent idiopathic scoliosis (AIS), hybrid constructs with pedicle-screw fixation in the lumbar spine and other anchors in the thoracic spine have been reported to provide to be of more physiological value in postoperative thoracic kyphosis than all-screw constructs. The Universial Clamp (UC) equipped with a soft sublaminar band is a relatively new thoracic anchor that can be used in hybrid constructs. A dedicated reduction tool that applies traction to the sublaminar band permits gentle translation of the thoracic curve to the precontoured fusion rods, which have been previously anchored distally by pedicle screws and proximally by hooks in a claw configuration. The aim of this study was to evaluate radiographic results of AIS treatment using UC hybrid constructs., Methods: This was a prospective case series in which 29 consecutive patients with Lenke type 1, 2 or 3 AIS operated on by two surgeons in two centers were followed for 24 months. Necessity for anterior release was an exclusion criterion., Results: A total of 5.4 ± 1.4 UCs were used per patient. The major thoracic curve was reduced from 55 ± 7° to 14 ± 6° at 1 month and 17 ± 6° at 24 months (correction 70%) without complications. In the patients who had less than 20° of T5-T12 kyphosis preoperatively, thoracic kyphosis improved from 14 ± 4° to 20 ± 3° at 3 months and 24 ± 9° at 24 months. In the other patients, preoperative thoracic kyphosis (27° ± 6°) was unchanged by the operation., Conclusion: UC hybrid constructs appear to safely provide satisfying coronal correction while consistently improving thoracic kyphosis in patients who also have preoperative hypokyphosis. We hypothesize that diminution in thoracic kyphosis was consistently avoided due to the straightforward traction of the spine to the fusion rods into which the chosen kyphosis was contoured by the surgeon before applying the reduction tool to the sublaminar bands.

Background: Bone reconstruction after surgical resection of malignant bone tumor in children remains a difficult challenge and various techniques exist. Induced membrane reconstruction as described by Masquelet et al has been reported in traumatic large bone defects. We have been using this 2-stage technique after primary malignant bone tumors resection in children since 2000., Methods: We retrospectively studied 12 cases: 6 Ewing sarcomas and 6 osteosarcomas. Mean age of the patients was 9 years old (range, 3 to 15.5 y). Surgical treatment consisted of wide resection and insertion of a cement spacer then secondary bone grafting. All patients had neoadjuvant and adjuvant chemotherapy and 2 patients had adjuvant radiotherapy., Results: Surgical excision was complete in all cases. There was no local recurrence at 6.2 years (range, 4.6 to 9.1 y) follow-up. Three patients had pulmonary metastasis (of whom 1 deceased) and 1 had a metastasis on the contralateral limb. The 11 patients operated on the lower limb achieved weight bearing 4.1 months (range, 0.2 to 14.2 mo) after the second stage of the procedure. Complications were numerous with 7 nonunions (4 unifocal and 3 bifocal), 5 fractures (in 4 patients), 5 protruding wires (in 4 patients), and 2 femoral varus deformities. There was no infection., Conclusions: Induced membrane reconstruction seems to be a simple and reliable technique in pediatric bone tumors and these results are promising. Extended use of locking nails could reduce the high rate of nonunion though it is not always possible in skeletally immature patients., Level of Evidence: IV (case series).

The total synthesis of enantiopure 4-epi-(+)-codonopsinine was achieved in 10 steps starting from D-ribose as a chiral building block. The key step involved a highly stereoselective nucleophilic addition of a Grignard reagent to a protected ribosylamine. Synthesis of the N-desmethyl derivative and its p-tolyl analogue was also accomplished, and the compounds were assayed against α-fucosidase.

Introduction: Treatment of symptomatic discoid meniscus in children is saucerization performed under arthroscopy. The strategy to adopt for associated meniscus lesions is discussed, from partial meniscectomy to meniscal repair. The latter was applied in the series studied herein. The objective was to assess this surgical strategy., Patients: This was a retrospective study of 20 discoid menisci (18 patients) operated between 2004 and 2007., Method: The patients first underwent arthroscopic saucerization and then, a procedure that depended on the residual meniscus: no additional procedure if there was no lesion, suturing or reinsertion in cases with a repairable lesion, and partial meniscectomy in cases of a non repairable lesion. All patients were assessed clinically and with postoperative MRI., Results: The mean follow-up was 37 months. Five discoid menisci presented no lesion and were treated with isolated saucerization. Fifteen discoid menisci presented a lesion. In four cases, saucerization removed this lesion. In eight cases, we performed meniscal repair after saucerization. In three cases, partial meniscectomy was necessary. The Lysholm score ranged from 67 to 88. Sixteen patients were satisfied or very satisfied in 16 cases. The mean Tegner score was 5.9. Postoperative MRI showed no signs of chondral degeneration. The mean measurements of the residual meniscus corresponded to the guidelines. Patients having undergone saucerization associated with meniscal repair had better results than those who had partial meniscectomy or meniscus repair alone (P=0.007, Fisher test)., Discussion: No other study having evaluated discoid meniscus surgery with postoperative MRI has been reported and few studies have been published on saucerization associated with repair. This approach spares the meniscus, as confirmed by MRI, with the size of the residual meniscus within the guidelines. We obtained good clinical and anatomic results, with good healing of the meniscus and satisfactory measurements., (Copyright © 2011. Published by Elsevier Masson SAS.)

Background: Abnormal mechanical loading occurs in scoliosis as compared to normal spines. Intervertebral disc degeneration has been correlated with alteration of bone density in adjacent vertebral bodies. How vertebral end plate remodels in scoliosis and the consequences on disc homeostasis are not well understood. Permeability is a relevant physical measure to quantify mass transport in porous media. We hypothesized that effective permeability of the vertebral end plate was modified by growth modulation in a scoliosis animal model., Methods: Flexible asymmetric posterior instrumentation was undertaken on six healthy four-week-old pigs. Two sets of left pedicle screws were inserted and connected with a stainless steel cable. After two months, the apical intervertebral unit and three units located cranially and caudally, were harvested. One central and two lateral specimens were investigated using a previously validated method for measuring permeability., Findings: A three-dimensional deformity was obtained in all six animals with an average of 42° right thoracic curve, 44° lordosis and 21° rotation. Permeability was significantly greater in the center of the end plates than in the periphery and it was decreased by -45% towards the apex of the deformity. Fluid flow direction did not play a significant role. No significant difference was found between the convex side and the concave side., Interpretation: The end plate is a crucial zone for diffusive and convective transport and we showed in a scoliosis animal model that a growth modulation may decrease its effective permeability. The proposed methodology and associated results could help to understand degenerative changes in human spine., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Original palladium complexes involving (-)-ephedrine, (-)-norephedrine, L-prolinol, L-valinol and L-isoleucinol have been rapidly prepared in neutral or basic medium and simply purified. They have been fully characterized by classical analytical methods and four of them were characterized by X-Ray analysis. In parallel with the experimental work, HF-DFT(B3LYP/PCM) computations were performed to obtain additional structural information. Their antiproliferative properties have been evaluated and some complexes showed small activities especially towards HT29 human cancer cells.

Introduction: In the Wassel type IV classification category, the thumb is duplicated from the metacarpophalangeal joint; this abnormality accounts for approximately 50% of the cases of thumb duplication. Type IV is divided into four subtypes in which the IV-D type, or convergent (9% of cases), is the most complex form because both thumbs are hypoplastic with a divergent metacarpophalangeal joint and a convergent interphalangeal joint. Reconstruction is prone to axis deformity and ligament laxity, whereas the Bilhaut-Cloquet technique's main pitfall is nail dystrophy. We propose a modified Bilhaut-Cloquet procedure to avoid these complications., Material and Method: Four males (mean age: 11 months; range: 10-12 months) with IV-D thumb duplication were operated on using a modified Bilhaut-Cloquet procedure., Surgical Technique: The skin is preliminarily marked, taking into account the excision of the central skin and the more hypoplastic nail of the two (most often the radial nail). Both proximal phalanges are split longitudinally and the central halves discarded. An oblique osteotomy is performed at the base of the distal phalanx of the ulnar thumb duplicate (the less hypoplastic) and the radial wedge is excised. The same osteotomy is applied to the distal phalanx of the radial thumb duplicate, but the radial wedge is preserved. The proximal phalanx and the bases of the distal phalanx are joined by bone suture. Axis correction and ligament stability are thus achieved without nail surgery., Results: The patients were examined with a mean 24 months of follow-up (range: 12-36 months). The result was good in all four cases according to the Horii score., Discussion and Conclusion: This procedure combines an excision of the central part of the proximal phalanx and partial excision of the base of the distal phalanx. It provides axis correction and stabilization of the interphalangeal joint while avoiding subsequent nail dystrophy because a single nail is preserved. Preliminary results are encouraging: no axis deformity, instability or nail dystrophy has been noted. Nonetheless, the long-term results need to be evaluated., Level of Evidence: IV retrospective study., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Homeostasis of the intervertebral disc relies on nutrient supply and waste clearance through the dense capillary network that is in contact with the cartilage endplate (CEP). We developed a micro-computerized tomography (micro-CT) method to quantify the marrow contact channel surface (MCCS) with the CEP and to validate the hypothesis according to which MCCS was correlated to the effective permeability of the vertebral endplate (VEP) and influenced by the mechanical stimuli. The influence of compression loading on local vascularization was investigated. Six 4-week-old skeletally immature pigs were instrumented with left pedicle screws and rod at both T5-T6 and L1-L2 levels to create asymmetrical spine tethers. After 3 months of growth, three cylindrical specimens of the VEP (one central and two lateral right and left) were obtained from both the instrumented and the control levels. We used a previously validated method for measuring permeability. Micro-CT analysis (resolution 12 microm) yielded a gray-scale 2D-image of the discal end of each specimen converted into a binary 2D-image to derive the MCCS. Correlations between MCCS and effective permeability were assessed. Effective permeability and MCCS were significantly decreased compared to the control group especially on the tethered side (-41.5%, p = 0.004 and -52.5%, p = 0.0009, respectively). Correlations were significant and showed maximal value (r(2) = 0.430, p < 0.0001) on the tethered side involving maximal compressive loadings. Mechanical stimuli, due to unbalanced growth, altered the vascularization and the convective properties of the CEP. The cascade of mechanobiological events should offer perspectives for research on disc degeneration and attempted treatment., ((c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Study Design: Prospective comparative study on 100 patients with positive family history for idiopathic scoliosis., Objective: To evaluate the concordance rate for curve pattern and side in family members with idiopathic scoliosis., Summary of Background Data: The pathogenesis of idiopathic scoliosis has been the subject of extensive research. It is termed multifactorial with a genetic component. Similar curve shape has been reported in twins with idiopathic scoliosis., Methods: We included prospectively 100 patients with idiopathic scoliosis when a relative of them was also affected with idiopathic scoliosis, and spine radiographs were available for both. Concordance for curve pattern by Lenke classification and side between family members was analyzed., Results: Familial concordance rate for curve pattern and side was 66% (95% confidence interval, 57-75), whereas the expected random concordance rate was 26% (95% confidence interval, 17-34). The affected relative was in 27 cases a sibling, in 32 cases a parent, in 1 case an uncle, in 2 cases a cousin, in 2 cases a half sister, in 2 cases a grandmother. Concordance rate was 65% (27/42) in siblings' pairs and 67% (32/48) in parents/child's pairs., Conclusion: We report a high concordance rate for curve pattern and side between relatives with idiopathic scoliosis. Curve shape is likely to be genetically determined in familial scoliosis. It seems important that curve type is documented and considered in future genetic studies.

Background: Disc degeneration has been correlated with alteration of bone density of adjacent vertebral bodies. Abnormal mechanical loading appears in scoliosis as compared to normal spines. How vertebral endplate was remodelled in scoliosis is not well understood., Methods: We conducted a micro-CT analysis of subchondral bone of the vertebral endplate at the curve apex in a porcine scoliosis model. Two adjacent thoracic T(5)-T(6) and lumbar L(1)-L(2) levels were instrumented in six four-week-old pigs with a custom offset implant connected by a flexible stainless steel wire. Two months after implantation, three cylindrical specimens were harvested into the vertebral endplate of each of the scoliosis levels: centre, convexity and concavity, and from the dorsal T(9)-T(10) vertebral units obtained from nine three-month-old non-instrumented pigs used as controls. Micro-CT analysis was carried out on each specimen., Findings: In the concavity of the scoliotic spine, bone volume fraction, trabecular thickness, and trabecular separation significantly increased whereas in the convexity, only trabecular separation increased. Connectivity index and trabecular number decreased significantly., Interpretation: This was the first micro-CT study of subchondral bone microarchitecture of the scoliotic vertebral end plate. At the curve apex, increased compression in the concavity induced an osteogenic process. In the convexity, diminished compression caused an osteolytic process with a local resorption. Clinically, the unbalanced tissue remodelling could play a role in the convective and diffusive transports into the end plate, which is of prime importance for the segment homeostasis in scoliosis treatment with or without surgery., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Arthroscopic surgery for children and adolescents is developing fast, thanks to technical progress in adult arthroscopy, improved knowledge of child joint disorders, and instrument miniaturization. The specificity of arthroscopy in children lies, on the one hand, in the small joint size and, on the other, in the presence of neighboring growth plates. There also exist specific pathologies as well as differences in indications in pathologies common to children and adults. These specificities need to be known, and adapted techniques and equipment require to be used, given which arthroscopy is feasible even in infants. Growth plate must be respected, and the residual growth of the operated segment (e.g., in knee ligament reconstruction) needs to be known. Joint decoaptation often does not require traction, and any stress maneuvers (valgus/varus) need to be gentle. The knee is by far the most frequently implicated joint in child arthroscopy, partly due to a rise in sports injuries. There is a variety of traumatic pathologies (osteochondral or meniscal/ligament tears, etc.) and of indications. Arthroscopy in children is safe, given awareness of these indications and respect of certain precautions. The advantages over conventional open surgery are the same as in adults: simpler postoperative course, faster functional recovery and better esthetic result. Arthroscopy will continue to develop in pediatrics in coming years., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

We proposed a substructure technique to predict the time-dependant response of biological tissue within the framework of a finite element resolution. Theoretical considerations in poroelasticity preceded the calculation of the sub-structured poroelastic matrix. The transient response was obtained using an exponential fitting method. We computed the creep response of an MRI 3D reconstructed L(5)-S(1) intervertebral disc of a scoliotic spine. The FE model was reduced from 10,000 degrees of freedom for the full 3D disc to only 40 degrees of freedom for the sub-structured model defined by 10 nodes attached to junction nodes located on both lower and upper surfaces of the disc. Comparisons of displacement fields were made between the full poroelastic FE model and the sub-structured model in three different loading conditions: compression, offset compression and torsion. Discrepancies in displacement were lower than 10% for the first time steps when time-dependant events were significant. The substructuring technique provided an exact solution in quasi-static behavior after pressure relaxation. Couplings between vertical and transversal displacements predicted by the reference FE model were well stored by the sub-structured model despite the drastic reduction of degrees of freedom. Finally, we demonstrated that substructuring was very efficient to reduce the size of numerical models while respecting the time-dependant behavior of the structure. This result highlighted the potential interest of substructure techniques in large-scale models of musculoskeletal structures., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Purpose: Subchondral bone (SCB) of the vertebral endplates (VEP) is the principal site of changes in vertebral trabecular microarchitecture secondary to intervertebral disc degeneration. However, the microstructure of this region has not yet been clearly characterized., Methods: One thoracic and one lumbar vertebral unit (vertebra-disc-vertebra) was removed in nine pigs aged 4 months. Three samples (one central and two laterals) were taken from each VEP. Micro-CT examination and histomorphometric measurements of the subchondral trabecular bone of the VEP were carried out. Correlations between micro-CT and histological parameters were sought., Results: Trabecular network was significantly denser [increased bone volume fraction (BV/TV) and trabecular number (Tb.N), decreased intertrabecular separation (Tb.Sp)] in the cranial endplates of the vertebral units. It was also significantly denser and less well organized [increased degree of anisotropy (DA)] in the centre of the VEP. The thickness of the cartilage endplate (CEP), SCB and growth cartilage were significantly lower in the centre of the VEP. There was a significant negative correlation between BV/TV, Tb.N and DA with the thicknesses of the CEP and SCB whereas Tb.Sp was positively correlated with these two parameters., Conclusion: We observed densification of the trabecular network in the centre of the VEP overlying the nucleus pulposus, partly related to thinner hyaline cartilage. Densification is associated with more anisotropic architecture that could cause lower mechanical strength in this area. This study provides new information on the microarchitecture of the SCB of the VEP which will make it possible to validate future models.

A case of anterior inferior iliac spine fracture in 13-year-old twins is reported. Anterior inferior iliac spine avulsion fracture in adolescent remains a little known entity. We report identical fractures sustained 1 year apart in twin brothers with the same mechanism. Both recovered fully after conservative treatment. A review of the literature retrieved only a few reports of cases. Of interest were the delay between both the fractures and the difference in height between the two individuals. This lesion is likely to be multifactorial with different factors among which are genetics, age, and skeletal maturation, repeat bone stress along with acute indirect trauma.

Purpose: Evaluation of a novel instrumentation device for adolescent idiopathic scoliosis., Methods: A new osteosynthesis implant (Universal Clamp) primarily consisting of a sublaminar band and titanium clamp was prospectively studied in 32 patients (average age, 15 years) with a major thoracic curve., Results: The Universal Clamp was used without anterior release to reduce and maintain correction of the thoracic curve, which improved from 55.1° preoperatively to 14.5° at 3 months without neurological complication or loss of kyphosis., Conclusions: This implant distributes stress over a larger area of the laminar cortex than sublaminar wires, patently reducing the risk of laminar fracture for equivalent reduction forces, and permits progressive reduction at several apical levels simultaneously.

We conducted a micro-CT analysis of subchondral bone of the vertebral end-plates after application of compressive stress. Thoracic and lumbar vertebral units were instrumented by carrying out left asymmetric tether in eleven 4-week-old pigs. After 3 months of growth, instrumented units and control units were harvested. Micro-CT study of subchondral bone was performed on one central and two lateral specimens (fixated side and non-fixated side). In control units, bone volume fraction (BV/TV), number of trabeculae (Tb.N), trabecular thickness (Tb.Th), and degree of anisotropy (DA) were significantly higher, whereas intertrabecular space (Tb.Sp) was significantly lower in center than in periphery. No significant difference between the fixated and non-fixated sides was found. In instrumented units, BV/TV, Tb.N, Tb.Th, and DA were significantly higher in center than in periphery. BV/TV, Tb.N, and Conn.D were significantly higher in fixated than in non-fixated side, while Tb.Sp was significantly lower. We noted BV/TV, Tb.N, and Tb.Th significantly lower, and Tb.Sp significantly higher, in the instrumented levels. This study showed, in instrumented units, two opposing processes generating a reorganization of the trabecular network. First, an osteolytic process (decrease in BV/TV, Tb.N, Tb.Th) by stress-shielding, greater in center and on non-fixated side. Second, an osteogenic process (higher BV/TV, Tb.N, Conn.D, and lower Tb.Sp) due to the compressive loading induced by growth on the fixated side. This study demonstrates the densification of the trabecular bone tissue of the vertebral end-plates after compressive loading, and illustrates the potential risks of excessively rigid spinal instrumentation which may induce premature osteopenia., ((c) 2009 Orthopaedic Research Society.)