Residual Stresses in Surgical Growing Rods.

The treatment of early onset scoliosis using surgical growing rods suffers from high failure rate. Fatigue resistance can be improved by inducing compressive residual stresses within the near surface region. An in-depth investigation of the residual stresses profile evolution is performed through the sequence of material processing steps followed by surgeons handling operations, in connection to material properties. The final goal is to guide further improvements of growing rod lifetime. Residual stress evaluation was carried out on Ti-6Al-4V rods using digital image correlation applied to microbeam ring-core milling by focused ion beam. This provided experimental stress profiles in shot-peened rods before and after bending and demonstrated that compressive residual stresses are maintained at both concave and convex rod sides. A finite element model using different core and skin conditions was validated by comparison to experiments. The combination of an initial shot peening profile associated with a significant level of backstress was found to primarily control the generation of compressive stresses at the rod surface after bending. Guidelines to promote larger compressive stresses at the surface were formulated based on a parametric analysis. The analysis revealed the first order impact of the initial yield strength, kinematic hardening parameters and intensity of the shot peening operation, while the bending angle and the depth of shot peening stresses were found to be of minor importance. Materials exhibiting large kinematic hardening and low yield strength should be selected in order to induce compressive residual stresses at key fatigue initiation site.

A novel technique for treatment of progressive scoliosis in young children using a 3-hook and 2-screw construct (H3S2) on a single sub-muscular growing rod: surgical technique.

INTRODUCTION: Several different growing rod techniques have been described in the literature to treat progressive scoliosis in young children. Nevertheless, none of these techniques has shown a real superiority, and the rate of complications remains high. The purpose of this report is to describe an original fusionless method of treatment for this problem. MATERIALS AND METHODS: The 3 hooks-2 screws (H3S2) construct consists of a single 5.5 mm titanium rod with three hooks proximally and two monoaxial pedicle screws distally, and some extra length of rod located distally and/or proximally that can be used for future lengthenings. To date, a total of 103 H3S2 constructs have been performed in our institution. This paper reports the preliminary results on 38 patients, with a minimum follow-up of 2 years. RESULTS: This procedure was found to be effective in maintaining scoliosis correction while allowing continued spinal growth and was associated with a low rate of complications. CONCLUSIONS: The H3S2 construct was found to have several advantages over the growing rod techniques as previously described in the literature. These include no need for post-operative bracing, fewer lengthening procedures and a lower rate of complications.

H3S2 (3 hooks, 2 screws) construct: a simple growing rod technique for early onset scoliosis.

PURPOSE: The purpose of this study was to review the preliminary results of an original fusionless method of treatment for progressive scoliosis in young children. METHODS: This study retrospectively reviewed the clinical records and radiographs of 23 children with progressive scoliosis who failed to respond to conservative treatment and underwent fusionless surgery using a single solid growing rod construct. All of them were ambulatory and had a follow-up of minimum 2 years. Sixteen patients were treated by consecutive distraction of a single intramuscular rod, and seven patients with rodding and anterior apical convex fusion. The etiology of the scoliosis included 11 idiopathic, 6 syndromic, 4 congenital, and 2 neurofibromatosis. At initial surgery, the average age was 9.3 ± 2.8 years, with a mean Cobb angle of 68° ± 32°. Six patients underwent progressive scoliosis correction in a Stagnara cast prior to surgery, and one patient with an external halo-pelvic Ilizarov device. RESULTS: Fusionless single rodding allowed to maintain scoliosis correction in all patients. At an average of 3.5 ± 0.9 years after initial surgery, the 23 patients showed a correction of 57 % in the magnitude of the original curvature. Trunk height increase was documented in all patients and ranged from 1.5 to 11.9 cm. Rod failure was found in three patients and two patients had hardware infection. Only four cases of proximal junctional kyphosis were found at last follow-up. CONCLUSIONS: Preliminary results from these series of patients show that the presented fusionless single growing rod technique allows to maintain correction of progressive early onset scoliosis while permitting spinal growth, with low complication rate. With this technique, lengthening procedures are used only once in every 10 months and patients are more comfortable as no brace is needed in most cases. This technique does not require any specific spine device. The procedure is simple and efficacious as long as some guidelines are respected.

Very short-term effect of brace wearing on gait in adolescent idiopathic scoliosis girls.

PURPOSE: Adolescent idiopathic scoliotic (AIS) deformity induces excessive oxygen consumption correlated to a bilateral increase of lumbo-pelvic muscles timing activity (EMG) during gait. Wearing a brace, the usual treatment for AIS, by supporting the spine and the pelvis, would generate lumbo-pelvic muscular relaxation and consequently reduce excessive oxygen consumption. The purpose of this study was to evaluate the short-term effect of bracing on gait biomechanics in scoliotic spine when compared with normal braced spine. METHODS: Thirteen healthy volunteers were compared to 13 AIS girls. In both samples, gait analysis was assessed using a three-dimensional motion analysis, including synchronous kinematic, electromyographic, mechanical and energy measurements, first without brace, then wearing a brace. RESULTS: For scoliotic patients, comparison of in-brace and out-brace situations revealed a significant decrease of frontal pelvis (p < 0.001), hip (p < 0.001) and shoulder (p = 0.004) motion in brace associated with a significant reduction of pelvis rotation (p = 0.003). However, the brace did not change significantly the lumbo-pelvic muscle activity duration (EMG) or the mechanical and energetic parameters. Transversal pelvis motion was reduced by 39% (p = 0.04), frontal hip and shoulder motions by 23% (p = 0.004) and 30% (p = 0.01) respectively, and energy cost of walking remained increased by 37% in braced AIS girls relatively to braced healthy subjects. Mechanical and electromyographic variables were not significantly different between the two braced populations during gait except for the gluteus medius muscle that showed bilaterally an increase of duration of electrical activity in healthy subjects and contrarily a decrease in AIS patients (healthy: -3.5 ± 9.6% of gait cycle vs. scoliotic: 3.7 ± 7.7% of gait cycle; p = 0.04). CONCLUSIONS: Bracing changed neither the oxygen consumption nor the timing of the lumbo-pelvic muscles activity in both groups during gait. However, in brace the timing activity of bilateral gluteus medius muscles tended to decrease in AIS patients and increase in healthy subjects. Moreover, braced AIS patients had more restricted frontal hips and shoulder motion as well as pelvis rotation than braced healthy subjects.

Lombo-sacral joint efforts during gait: comparison between healthy and scoliotic subjects.

INTRODUCTION: The internal efforts in the human body in motion could provide valuable information for the evaluation and follow-up of subjects with musculo-skeletal pathologies, such as scoliosis, but are still difficult to accurately measure. In this context, the objective of this study is to compare the lombo-sacral (L5-S1) joint efforts during gait (i.e.: mediolateral forces, mediolateral torques, and anteroposterior torques) between typically developed adolescents (TDA) and adolescents with left lumbar or thoracolumbar idiopathic scoliosis (AIS), categorized by their Cobb angle (CA). MATERIAL AND METHODS: 12 TDA, 10 AIS with CA < 20°, 13 AIS with CA between 20° and 40° as well as 16 AIS in preoperative condition performed gait at 4 km/h on instrumented treadmill. Among the latter group, 8 AIS were evaluated after surgical intervention (participants with at least a diminution of 30° of their CA). The acquisition system measured the human body joint motion via optokinetic sensors, and the ground reaction forces via a treadmill fitted with force sensors. The L5-S1 intervertebral efforts were calculated using a tridimensional inverse dynamical model of the human body. RESULTS: The mediolateral forces were significantly higher for AIS with CA between 20° and 40° and for AIS in pre-operative condition compared to TDA values. But neither mediolateral nor anteroposterior torque was significantly different between groups. After surgical intervention the maximal anteroposterior torque was significantly lower compared to pre-surgical value. CONCLUSION: The participants with severe idiopathic scoliosis present higher L5-S1 mediolateral forces than TDA, which could lead to a supplementary asymmetric vertebra growth modulation and the progression of the scoliotic deformities in the framework of the Hueter-Volkman principle. Further research should include the tridimensional reconstruction of the spine in order to observe differences between categories of AIS patients in terms of dynamical behaviors along the spine.

A multibody-based approach to the computation of spine intervertebral motions in scoliotic patients.

In idiopathic scoliotic patients, dynamical intervertebral efforts acting between vertebrae seem to be correlated with the spinal deformity. The quantification of these efforts, which is useful for the orthopedic surgeons to set up their surgical planning is the final objective of the present research. As a first step, we focus in this contribution on the geometrical reconstruction of the spine and especially on the rotation sequences between vertebrae in a multibody approach. The reconstruction process is performed in the standing position with possible bending, using an optimization process based on geometrical data reconstructed from radiographs. The obtained results will serve as input for the subsequent gait motion for which the limited set of geometrical information must be compensated.

Leg length discrepancy following femoral shaft fracture in children: clinical considerations and recommendations.

Femoral shaft fracture in children is a frequently encountered problem. Residual leg length discrepancy persisting at skeletal maturity is the most common complication. In this study, a positive correlation was found between the amount of bone fragments overlap and the overgrowth phenomenon. When comparing final leg-length discrepancy with initial fragments overlap, 9.3 mm was found to be the maximal overlap to be tolerated in order to avoid significant leg length discrepancy.

Fracture mechanisms in Ti and Co-Cr growing rods and impact on clinical practice.

The widely used treatment of early onset scoliosis based on fusionless spinal instrumentation with growing rods suffers from severe complications due to premature rod failure. Only few studies have explored the fracture mechanisms in single rod constructs, while clinical practice urgently needs guidance. The objectives of this study are (i) to determine the failure mechanisms in Ti-6Al-4V alloy, Ti Cp 2 and Co-Cr alloy rods, and (ii) to propose strategies to reduce the risk of rod fracture. For this purpose, seven rods from three patients treated for early onset scoliosis were characterized by preoperative, pre-fracture X-rays and after-fracture X-rays. Fracture surface analysis, performed using scanning electron microscopy, revealed similar failure mechanisms for all rods, independent of composition and diameter. Fracture is caused by fatigue, associated to repeated bending action in the anteroposterior direction. Cracking initiates at multiple sites. Three-point bending fatigue tests on Ti-6Al-4V bent rods confirmed the fracture scenario. A beam bending model indicates that the failure process is controlled by the combination of cyclic vertical and horizontal forces with amplitudes from 200 N to 400 N and from 70 N to 150 N, respectively. Strategies to minimize fracture involve adaptations of material properties and rod geometry to scoliosis characteristics, including sagittal alignment, and spine behavior.

Comparison of three surgical epiphysiodesis techniques for the treatment of lower limb length discrepancy.

Three operative techniques for epiphysiodesis to correct lower limb length discrepancy (LLD) are compared: the Phemister technique, the percutaneous drilling-curettage technique and percutaneous epiphysiodesis using a transphyseal screw. Between 1987 and 2008, 92 patients with LLD were treated by surgical epiphysiodesis. Eighty patients were available for this retrospective study. No statistically significant difference was found between the three techniques concerning their efficiency in correction of lower limb length discrepancy. Percutaneous epiphysiodesis using a transphyseal screw appeared to be the best technique regarding mean operative time, mean hospitalisation time, postoperative pain and recovery of ambulation in the postoperative period. Complication rates were similar with the three techniques.

Three-dimensional correction of complex leg deformities using a software assisted external fixator.

The Taylor Spatial Frame is a computer assisted hexapod system allowing simultaneous correction of every component of complex limb deformities (leg length discrepancy, angulation, translation and rotation). We report our experience with this system in six patients. The planned correction was achieved in all cases. Minor complications occured in all but one patient without consequences; there were four major complications: non union, callus fracture, plantar aponeurosis retraction and reflex sympathetic dystrophy in one case each. These complications were not in relation with the type of fixator used. In patients requiring correction of complex deformities, the Taylor Spatial Frame is a useful device that simplifies the planning procedure and allows simultaneous correction of any deformity in every plane. Another major advantage is the possibility to correct any residual deformity at the end of the planned procedure.

Gait in patients with adolescent idiopathic scoliosis. Effect of surgery at 10 years of follow-up.

PURPOSE: To assess radiological and gait biomechanical changes before, at one and 10 years after surgery in AIS patients. METHODS: This clinical prospective study included fifteen adult women (mean[SD] age: 26 [1] years) diagnosed with thoraco-lumbar/lumbar AIS and operated 10 years ago. Clinical, radiological and gait variables, including kinematics, electromyography (EMG), mechanics and energetics were compared between presurgery (S0), 1 year (S1) and 10 years (S2) postsurgery period using a one way repeated measure ANOVA. RESULTS: The Cobb angle of the scoliosis curve was reduced by 55% at 1 year postsugery but only by 37% at 10 years postsurgery suggesting a loss of 32% over time. Frontal plumb line C7-S1 distance was significantly improved by surgery (-44%) and remained stable at 10 years postsurgery. Lower limb kinematics was not affected by the surgery at long term. Excessive bilateral activation of lombo-pelvic muscles, observed before surgery, decreased significantly at S1 and S2 period. Mechanical energy increased significantly between S0, S1 and S2 session, without any change for the energetic variables. CONCLUSIONS: Between 1 and 10 years post-surgery, thoraco-lumbar/lumbar AIS women showed a few decompensation of the curve without any change of the improved frontal body balance. Lower limbs and pelvic motion, during gait, was not affected by the surgery. But presurgical excessive EMG activity of the lumbo-pelvic muscle and reduced mechanical energy produced to walk get similar to normal patterns. Only the oxygen consumption remained excessive probably due to physical deconditioning or postural instability.

The use of allografts in paediatric orthopaedic surgery.

Autograft harvesting in a growing child sometimes leads to disastrous consequences. Allograft can advantageously replace autograft in the majority of the cases. This overview presents the most frequently used allografts in paediatric orthopaedic surgery and discusses their benefits. Illustrative cases are presented to highlight specific indications.

Focal fibrocartilaginous dysplasia of the tibia: long-term evolution.

Focal fibrocartilaginous dysplasia of the tibia (FFCD) is a rare and benign condition associated with unilateral tibia vara in childhood. The first description was done by Bell in 1985. Since then more than sixty cases have been reported. The aetiology remains unknown. Five new cases are retrospectively reported. Four of them with tibia vara less than 30 degrees showed a spontaneous correction. One patient had a severe varus deformity (> 30 degrees) leading to physeal impairment and underwent a tibial valgus osteotomy. Biopsy is not necessary as radiographs are typical. The infantile growth plate is able to correct a tibia vara due to FFCD if less than 30 degrees. In case of spontaneous resolution, a long-term follow-up remains necessary because of a possible progressive leg length discrepancy.

Orthopaedic complications associated with sickle-cell disease.

Sickle cell disease is the most frequent haemoglobinopathy in the world. It affects mostly African descent, but is also present in whites in Greece, Turkey, Italy and India. The responsible gene is autosomal co-dominant and only individuals homozygous for the gene are symptomatic. The condition is characterised by haemolytic anaemia crises and cardio-pulmonary, digestive, neurological, ocular and osteo-articular manifestations. Osteo-articular complications are frequent and may compromise harmonious growth. This retrospective study reports the osteo-articular complications associated with sickle-cell disease encountered in our institution from 1975 to 2004. Orthopaedic complications were reported in 79 patients out of 325 who were followed with sickle-cell disease.

Orthopaedic manifestations of Brachmann-de Lange syndrome: a report of 34 patients.

Brachmann-de Lange syndrome (BDLS) is a disorder of unknown cause that is recognized on the basis of characteristic facies in association with growth retardation, mental retardation and, in many cases, upper limb anomalies. Because of its association with skeletal anomalies, patients with the syndrome are often referred to the paediatric orthopaedic surgeon. Thirty-four patients with Brachmann-de Lange syndrome were evaluated for the prevalence and pattern of musculoskeletal involvement. The average age of the patients was 10.2 years (range, 1 month to 44 years). Both sexes were affected equally. The common orthopaedic manifestation affected the hand (100%), elbow (47%), and the heel cord (26%). Severe bony anomalies included complete absence of the hand in one case, and ulna hemimelia in two cases. In two patients bilateral Legg-Perthes-like changes were noted. Scoliosis presented in four cases, all before the age of 10 years. Surgery was performed in two patients with severe bilateral equinovarus feet. Despite the constellation of musculoskeletal findings, most of the patients did not have surgical intervention for their deformities.

MRI abnormalities of the ischiopubic synchondrosis in children: a case report.

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.

Orthopaedic concerns in children with growth hormone therapy.

Growth hormone (GH) therapy is widely used in children; it may have various severe orthopaedic complications. Slipped capital femoral epiphysis, Legg-Calvé-Perthes disease, scoliosis and carpal tunnel syndrome may occur with GH treatment. Before beginning GH therapy, it is important to take into account all the risk factors of the individual patient, as some conditions could contraindicate GH treatment. During GH treatment, close monitoring with both clinical and radiographic examination is mandatory. The paediatric orthopaedic surgeon will frequently be asked about the management of these complications and about the necessity for treatment arrest. The authors review the orthopaedic complications which the orthopaedic surgeon may encounter in patients treated with GH.

Effect of long-term orthotic treatment on gait biomechanics in adolescent idiopathic scoliosis.

BACKGROUND CONTEXT: A previous study showed subtle biomechanical changes in the gait of unbraced adolescent idiopathic scoliosis (AIS) patients such as a reduction of pelvic, hip, knee, and ankle displacements. However, lumbopelvic muscles' timing activity was bilaterally increased during gait and correlated to excessive oxygen consumption as compared with healthy subjects. Usually, a brace, when indicated, is worn strictly for 22 hours every day in skeletally immature idiopathic scoliotic girls. To our knowledge, no study has assessed the long-term brace effect (6 months) on functional activities such as level walking. PURPOSE: To assess the stiffening effects of 6 months' brace wearing on instrumented gait analysis in girls with thoracolumbar/lumbar adolescent idiopathic scoliosis. STUDY DESIGN/SETTING: Clinical prospective study. PATIENT SAMPLE: Thirteen girls diagnosed as progressive adolescent idiopathic scoliosis with left thoracolumbar/lumbar curves (curves ranging 25°-40°). OUTCOME MEASURES: All patients underwent a radiographic and instrumented gait analysis, including assessment of kinematics, mechanics, electromyography (EMG), and energetics of walking. METHODS: The scoliotic girls were prospectively studied at S1 (before bracing) and 6 months later at S2 (out-brace: treatment effect). The gait parameters were compared with those of 13 matched healthy girls. A t paired test was conducted to evaluate the effect of the 6-month orthotic treatment in AIS girls. Student t test was performed to compare the scoliotic group at S2 and the healthy subjects to identify if the observed changes in gait parameters meant improvement or worsening of gait. RESULTS: After 6 months of orthotic treatment in AIS, thoracolumbar/lumbar curves and apical rotation remained reduced by 25% and 61%, respectively. During gait, frontal pelvis and hip motions were significantly increased. Muscular mechanical work increased becoming closer but still different as compared with healthy subjects. Bilateral lumbopelvic muscles were almost 40% more active in AIS at S1 compared with healthy subjects and did not change at S2 except for the erector spinae muscles EMG activity, which decreased significantly. Energy cost exceeded by 30% in AIS at S1 compared with healthy subjects and did not change at 6 months' follow-up. CONCLUSIONS: After 6 months of orthotic treatment, in an out-brace situation, the main structural thoracolumbar/lumbar curve remained partly corrected. Frontal pelvis and hip motion increased, contributing to an improvement of muscular mechanical work during walking. EMG activity duration of lumbopelvic muscles did not change except for the erector spinae muscles, which was decreased but without any beneficial change in the energy cost of walking. In summary, brace treatment, after 6 months, did not significantly influence the gait variables in AIS girls deleteriously, but did not reduce the excessive energy cost, which was 30% above the values of normal adolescents.

Chronic osteomyelitis of clavicle as primary manifestation of SAPHO syndrome in adolescents: report of four cases and long-term evolution.

Four cases of chronic osteomyelitis of clavicle as primary manifestation of synovitis, acne, pustulosis, hyperostosis, osteomyelitis (SAPHO) are reported in adolescents. In all cases a typical radiographical evolution had been observed with progressive slow migration of sclerotic area from medial to lateral side of clavicle. Long-term evolution was alternation of remission and exacerbation but none of the patients healed.