Cartilaginous tibial eminence fractures in children: which recommendations for management of this new entity?

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.

The difficult diagnosis of cartilaginous tibial eminence fractures in young children.

PURPOSE: Anterior tibial eminence fracture is the main mode of ACL failure in patients with open physes. In young children, purely cartilaginous avulsions of the tibial ACL insertion are possible. The aim of this study was to focus on patients referred for misdiagnosed cartilaginous tibial eminence fractures. METHODS: Ten young patients with cartilaginous tibial eminence fractures were identified in the hospital database. Six of them were misdiagnosed and included in this retrospective case series. Clinical data at the time of injury, radiographs and MRI were analysed in order to evaluate the causes which could have led to inappropriate management. RESULTS: The patients' median age at the time of injury was 7 years (5-8.5). The main cause of injury was a low-energy domestic accident (n = 4). Radiographs at the time of injury were normal (n = 4) or showed a very thin ossification (n = 2). The traditional MRI findings of ACL injuries were all negative. On T2 sequences, an epiphyseal fluid signal allowed for a retrospective diagnosis. Cartilaginous tibial eminence fractures were regularly prolonged posteriorly giving a 'double-PCL sign' in 4 of the 6 patients. On a median of 6 months (2.5-48) after the injury, patients were referred for repeat giving ways (n = 5) and/or limitation of extension or hyperextension (n = 4). Symptoms were related to non-union, ossification and secondary enlargement of the avulsed fragment. CONCLUSIONS: Post-traumatic knee joint effusions in children aged 9 or younger, even occurring after a low energy trauma and with normal radiographs, should suggest a cartilaginous tibial eminence fracture. Systematic MRI examinations should be mandatory in these patients in whom the avulsed fragment may appear as a double-PCL sign. During follow-up, new radiographs are recommended. A better knowledge of this rare entity should allow us to avoid misdiagnosis and to perform an early refixation of the avulsed fragment.

Jacobsen and Beckwith-Wiedemann syndromes in a child with mosaicism for partial 11pter trisomy and partial 11qter monosomy.

We report on a child with Jacobsen syndrome (JBS, OMIM 147791) and abnormalities consistent with Beckwith-Wiedemann syndrome (BWS, OMIM 130650). The constitutional karyotype was apparently normal, but FISH analysis with probes specific for the short and long arms of chromosome 11 found 11qter deletion with 11pter trisomy in 80% of the cells studied. Array-CGH identified breakpoints in the 11p15.3 and 11q24.1 regions consistent with Jacobsen and Beckwith-Wiedemann syndromes. We suggest that this chromosome imbalance results from a pericentric inversion of chromosome 11 inherited from the father, with mosaicism resulting from meiotic recombination of a paternal inversion followed by mitotic recombination during the first embryonic divisions. This hypothesis is supported by the results of microsatellite marker analysis. Three previous cases of pericentric inversion and recombination of chromosome 11 have been reported. Our case is unusual in that it combines the Jacobsen and Beckwith-Wiedemann syndromes with mosaicism.

Comparative study: Ponseti method versus French physiotherapy for initial treatment of idiopathic clubfoot deformity.

BACKGROUND: Nonoperative treatment avoids the complications after extensive surgery for idiopathic clubfeet. The purpose of this study was to compare retrospectively French physiotherapy and Ponseti method used to treat idiopathic clubfoot in 2 institutions. METHODS: Two hundred nineteen idiopathic clubfeet (146 patients) managed during a 3-year period (2000 to 2003) were included in this study: 116 clubfeet in group FM were treated according to modified French physiotherapy (with percutaneous heel-cord tenotomy in 17%) and 103 clubfeet in group PM were treated according to the Ponseti method. The use of further surgery was considered as failure of the nonoperative management: complete posteromedial release were noted poor, limited posterior release were noted fair, and nonrelease surgery or nonoperated feet were scored with the modified Ghanem score. RESULTS: After a mean follow-up of 5.5 years (range, 2.5 to 7.4 y), similar rate of surgery was performed in both groups (21% in group FM and 16% in group PM) but complete posteromedial release was mainly done in group FM (19% of feet), and limited surgery was done in group PM. Results were noted excellent, good, fair, and poor in respectively 55%, 20%, 6%, and 19% of patients in group FM and 79%, 15%, 4%, and 2% of patients in group PM. Results for Dimeglio grade II clubfeet were not different, but results for grade III and grade IV clubfeet were better in PM group. CONCLUSIONS: Ponseti method enables reduction of extensive surgery compared with French physiotherapy mainly for severe deformities.

Growth disturbances without growth arrest after ACL reconstruction in children.

Growth arrest is a major concern after ACL reconstruction in children. It usually occurs in patients near to closure of the growth plates. Growth disturbances without growth arrest are also possible and more vicious; the authors analyse the mechanism of two patients with growth disturbance due to overgrowth following ACL reconstruction. One was a symmetrical overgrowth process with 15 mm limb length discrepancy treated with percutaneous epiphysiodesis. Full correction at the time of skeletal maturity was achieved. The second patient developed an asymmetrical overgrowth with progressive tibial valgus deformity. This mechanism was similar to a posttraumatic tibial valgus deformity. After nonoperative treatment, a spontaneous correction of the deformity was noticed. Both children were young (7 and 10 years old) at the time of ACL reconstruction with an autologous iliotibial band graft. The clinical relevance of overgrowth disturbance is usually limited when compared to growth arrest but could require a second surgical procedure as reported in this study. Parents must be informed that even in experienced hands, and despite the use of a physeal sparing technique, this specific risk of growth disturbance is still present.

Latex allergy in children: modalities and prevention.

Allergic or immediate hypersensitivity reactions to latex have been reported in children with increasing frequency in the past. The reported prevalence varies greatly depending upon the population studied and the methods used to detect sensitization. Children's subpopulations at particular risk include: atopics, individuals with spina bifida, children undergoing surgical procedure during the neonatal period and individuals who required frequent surgical instrumentations. Latex allergy is also an important medical issue, particularly for healthcare personnel. Sensitization mainly occurs by wound or mucosal contact with latex devices during surgery or by inhalation of airborne allergens released from powdered latex gloves. Regarding diagnosis, the medical history, skin prick test and search for specific serum IgE are crucial but cost effective. The development of a guide listing latex-containing drugs is essential for the primary prevention of allergic reactions. Immunotherapy or specific premedication seems not effective in preventing the risk of anaphylaxis during the perioperative course. The most effective strategy to decrease the incidence of latex sensitization is complete avoidance. This strategy is efficient in patients and also in health care workers and has been applied since 2002 in our pediatric surgical hospital. One of major problem with the latex-free gloves was that surgeons find them considerably more difficult to work with. But today, manufacturers made considerable effort and free-latex gloves with an equal tactile sensation than the latex-gloves are now available. The extra cost of free latex gloves is well counterbalanced as allergen test, long stay hospital for allergic reaction, and worker's compensation are no longer needed. Since the introduction of this program in our institution, no allergic reaction to latex has been reported in 25000 anesthetized children or with the health care workers.

Rupture of the anterior cruciate ligament in children: early reconstruction with open physes or delayed reconstruction to skeletal maturity?

The purpose of this study was to compare two different strategies of management for ACL rupture in skeletally immature patient. In group 1, patients were treated in a children hospital by ACL reconstruction with open physis. In group 2, patients were treated in an adult hospital by delayed reconstruction at skeletal maturity assessed radiologically. Fifty-six consecutive patients were included in this retrospective study. Mean time from injury to surgery in group 1 and 2 was, respectively, 13.5 and 30 months. Patients from group 2 exhibited a higher rate of medial meniscal tears (41%) compare to group 1 (16%) and higher rate of meniscectomy. Both groups had the same rate of lateral meniscal tears. A temporary tibial valgus deformity was reported which was subsequently spontaneously resolved. No definitive growth disturbance was noticed. At 27 months mean follow-up, a best subjective IKDC score was found in group 1. Objective IKDC and radiological results were similar in both groups. Early ACL reconstruction is therefore a recommended option.

Slotted acetabular augmentation, alone or as part of a combined one-stage approach for treatment of hip dysplasia in adolescents with cerebral palsy: results and complications in 19 hips.

BACKGROUND: Surgical correction for the challenging combined deformities in hip dysplasia associated with cerebral palsy remains controversial. The purpose of this study was to assess the efficacy and determine the role of slotted acetabular augmentation (SAA) for the treatment of neuromuscular hip dysplasia in comparison with other treatment options. METHODS: We retrospectively analyzed 19 dysplastic hips in 19 patients with cerebral palsy who underwent SAA, alone or as part of a combined 1-stage approach, consisting of soft tissue lengthening and/or a proximal femoral osteotomy, during a 20-year period. RESULTS: The mean age at the time of operation was 14 years and 7 months (range: 12 to 17 years and 11 months). All had a closed triradiate cartilage. In 13 hips, preoperative radiographs showed major aspheric femoral head deformities. All had subluxation or dislocation of the hip and severe acetabular dysplasia, associated with a painful hip in 15 patients. Before operation, the mean migration index was 64+/-18%, the mean Sharp angle was 51+/-4 degrees, and the mean center-edge angle was -4+/-13 degrees. On immediate postoperative radiographs, they were 3+/-5%, 35+/-5 degrees, and 42+/-11 degrees. At final follow-up, the average migration index was 10+/-8%, the mean Sharp angle was 35+/-6 degrees, and the mean center-edge angle was 39+/-13 degrees. Eleven hips required soft tissue lengthening and 5 hips had a proximal femoral osteotomy at the time of the shelf procedure. At the latest follow-up (mean duration: 5 years and 5 months), 16 of the 19 hips remained anatomically reduced. CONCLUSIONS: Our results suggest that SAA is a successful procedure to treat advanced neurogenic acetabular dysplasia with or without femoral head deformities in skeletally mature patients.

Specific real-time polymerase chain reaction places Kingella kingae as the most common cause of osteoarticular infections in young children.

BACKGROUND: The use of universal 16S rDNA polymerase chain reaction (PCR) has recently shown that the place of Kingella kingae in osteoarticular infections (OAI) in young children has been underestimated, but this technique is not the most sensitive or the most rapid method for molecular diagnosis. We developed a specific real-time PCR method to detect K. kingae DNA and applied it to the etiologic diagnosis of OAI. PATIENTS AND METHODS: All children admitted to a pediatric unit for OAI between January 2004 and December 2005 were enrolled in this prospective study. Culture-negative osteoarticular specimens were tested by 16S rDNA PCR and by K. kingae-specific real-time PCR when sufficient sample remained. RESULTS: By culture alone, a pathogen was identified in 45% of the 131 specimens tested (Staphylococcus aureus, n = 25; K. kingae, n = 17; others, n = 18). 16S rDNA PCR and K. kingae-specific PCR were both applied to 61 of the culture-negative samples. The combination of culture and 16S rDNA PCR identified a pathogen in 61% of cases (K. kingae DNA, n = 16; DNA of other microorganisms, n = 5). Specific real-time PCR identified a further 6 cases caused by K. kingae and confirmed all 16 universal PCR-positive cases, bringing the overall documentation rate to 66%. K. kingae was the leading cause of OAI in this pediatric series (n = 39, 45%), followed by S. aureus (n = 25, 29%) CONCLUSION: The K. kingae-specific real-time PCR places K. kingae as the leading cause of OAI in children at our hospital.

A specific closed percutaneous technique for reduction of Jeffery type II lesion.

Open reduction is commonly recommended in Jeffery type II fractures. Attempts to reduce these fractures percutaneously were reported as unsafe and unreliable. We revisited this technique and used a specific percutaneous reduction that turned out to be successful in two cases. Instead of lifting the radial head as described in leverage maneuver, we use a pushing-back procedure to reduce the fracture. The maneuver aims at suppressing the capitellum interposition between the head fragment and the metaphysis by reproducing the reversed trajectory of trauma. This reduction is made possible because of the posterior periosteal attachment of the radial head. A few weeks after the procedure, the two patients remained painless, recovered a complete range of motion in prono-supination and returned to sports. In these two cases, the procedure used led to a prompt recovery and provided a much better outcome than described with the classic open approach.

Contribution of a broad range polymerase chain reaction to the diagnosis of osteoarticular infections caused by Kingella kingae: description of twenty-four recent pediatric diagnoses.

BACKGROUND: Microbiologic diagnosis of septic arthritis and osteomyelitis in children is hindered by the less than optimal yield of blood and osteoarticular fluid cultures. PATIENTS AND METHODS: All patients admitted to a pediatric unit for osteoarticular infections (OAI) between January 2001 and February 2004 were enrolled in this prospective study. Osteoarticular fluid and biopsy samples that were negative by conventional culture were tested by polymerase chain reaction (PCR) with universal 16S ribosomal DNA primers. RESULTS: We enrolled 171 children. Culture was positive in 64 cases (37.4%), yielding Kingella kingae in 9 cases. The 107 culture-negative specimens were tested by 16S ribosomal DNA PCR. Fifteen samples (14%) were positive, all for Kingella DNA sequences. K. kingae was the second cause of OAI in this population (30.4%), after Staphylococcus aureus (38%). Patients with Kingella infection diagnosed by culture (9 cases) did not differ from those diagnosed by PCR (15 cases) in terms of their clinical characteristics (including prior antibiotic therapy). The characteristics of the 24 children with arthritis (n = 17) or osteomyelitis (n = 7) were similar to those reported elsewhere. Fever (>38 degrees C) and symptom onset shortly before hospitalization (median, 4.5 days) were significantly associated with arthritis. CONCLUSION: Use of molecular diagnostic methods increases the identification of K. kingae in osteoarticular infections.

Functional variants of POC5 identified in patients with idiopathic scoliosis.

Idiopathic scoliosis (IS) is a spine deformity that affects approximately 3% of the population. The underlying causes of IS are not well understood, although there is clear evidence that there is a genetic component to the disease. Genetic mapping studies suggest high genetic heterogeneity, but no IS disease-causing gene has yet been identified. Here, genetic linkage analyses combined with exome sequencing identified a rare missense variant (p.A446T) in the centriolar protein gene POC5 that cosegregated with the disease in a large family with multiple members affected with IS. Subsequently, the p.A446T variant was found in an additional set of families with IS and in an additional 3 cases of IS. Moreover, POC5 variant p.A455P was present and linked to IS in one family and another rare POC5 variant (p.A429V) was identified in an additional 5 cases of IS. In a zebrafish model, expression of any of the 3 human IS-associated POC5 variant mRNAs resulted in spine deformity, without affecting other skeletal structures. Together, these findings indicate that mutations in the POC5 gene contribute to the occurrence of IS.

Complete dislocation of the radial head following fracture of the radial neck in children: the Jeffery type II lesion.

The authors report four cases of Jeffery type 2 lesions in children. Despite the probable mechanism of such lesions, none of the cases reported here displayed a dislocation of the elbow. In the first observation the diagnosis was suspected only 15 days after injury. Two other cases were initially treated by closed external manipulations, one with percutaneous Kirschner wire leverage and the other with closed intramedullary pinning, but both cases displayed a 180 degree reversal of the radial head, suspected only secondarily. The first exhaustive review of the literature on the subject, shows that this complication is classical in Jeffery type 2 fractures. In fact none of the 22 cases described in the literature had successfully been reduced by external manipulations. Interposition of the lateral condyle, pathognomonic of the Jeffery type 2 fracture, hampers reduction. Attempts at reduction by external manipulation in nine cases therefore led to two non-reduction and seven reversal of the radial head. Knowledge of this particular fracture will allow an early diagnosis and an immediate surgical treatment.

Predicting intraoperative feasibility of combined TES-mMEP and cSSEP monitoring during scoliosis surgery based on preoperative neurophysiological assessment.

BACKGROUND CONTEXT: Combined monitoring of muscle motor evoked potentials elicited by transcranial electric stimulation (TES-mMEP) and cortical somatosensory evoked potentials (cSSEPs) is safe and effective for spinal cord monitoring during scoliosis surgery. However, TES-mMEP/cSSEP is not always feasible. Predictors of feasibility would help to plan the monitoring strategy. PURPOSE: To identify predictors of the feasibility of TES-mMEP/cSSEP during scoliosis surgery. STUDY DESIGN/SETTING: Prospective cohort study in a clinical neurophysiology unit and pediatric orthopedic department of a French university hospital. PATIENT SAMPLE: A total of 103 children aged 2 to 19 years scheduled for scoliosis surgery. OUTCOME MEASURES: Feasibility rate of intraoperative TES-mMEP/cSSEP monitoring. METHODS: All patients underwent a preoperative neurological evaluation and preoperative mMEP and cSSEP recordings at both legs. For each factor associated with feasibility, we computed sensitivity, specificity, positive predictive value (PPV), and negative predictive value. A decision tree was designed. RESULTS: Presence of any of the following factors was associated with 100% feasibility, 100% specificity, and 100% PPV: idiopathic scoliosis, normal preoperative neurological findings, and normal preoperative mMEP and cSSEP recordings. Feasibility was 0% in the eight patients with no recordable mMEPs or cSSEPs during preoperative testing. A decision tree involving three screening steps can be used to identify patients in whom intraoperative TES-mMEP/cSSEP is feasible. CONCLUSIONS: Preoperative neurological and neurophysiological assessments are helpful for identifying patients who can be successfully monitored by TES-mMEP/cSSEP during scoliosis surgery.

Continued growth of the hip after fixation of slipped capital femoral epiphysis using a single cannulated screw with a proximal threading.

BACKGROUND: The most commonly used method for unstable slipped capital femoral epiphysis (SCFE) remains in situ fixation. Depending on the surgeon's preference, screws or Kirschner wires are used for stabilizing the slipped upper femoral epiphysis. The purpose of this study was to evaluate the ability of a single cannulated screw with a proximal threading to ensure stabilization, growth, and remodeling of the slipped epiphysis. METHODS: A retrospective study was performed identifying 23 children treated for unstable SCFE under 50° by means of a single cannulated screw with proximal threading. All patients attended a radiological evaluation immediately after surgery and at physeal closure. The width of the epiphysis cut by the Klein line, the width and length of the femoral neck, the centrocalcar distance (CCD) angle, and the articulotrochanteric distance (ATD) were evaluated. RESULTS: All patients had a stabilized epiphysis at the last follow-up, with no case of recurring slip. Radiological comparison of the affected side between the preoperative and the last follow-up evaluation showed a statistically significant improvement in the neck length and width. CONCLUSION: Fixation of the epiphysis using proximally threaded screws allows the preservation of femoral neck growth. The cannulated screw with proximal threading seems to be a safe and relevant implant to help to restore a close-to-normal hip at skeletal maturity.

Failed vascularized proximal fibular epiphyseal transfer for hip reconstruction following infection in children.

PURPOSE: Treatment of the sequellae of hip infection with epiphyseal destruction in children has had limited success to date. The aim of this study was to report mid-term results after hip epiphyseal reconstruction using a proximal vascularized fibular graft in three children presenting with massive epiphyseal destruction of the proximal femur following infection. METHODS: Three children suffered from hip articular destruction type IVB according to the Choi classification after neonatal septic arthritis. The mean age at reconstruction was 4.3 years (range 3-6 years). The Hunka et al. criteria were used to evaluate the functional results, and the clinical evaluation was based on the Musculo-Skeletal Tumor Society (MSTS) score. Growth and fusion of the graft and hip morphology were evaluated on simple X-rays and by magnetic resonance imaging (MRI). A ratio between cephalic diameter and inter-acetabular gap was defined on the MRI scan as the "acetabular filling index". RESULTS: No intraoperative complication was reported. With a mean follow-up of 4.8 years (3-6 years), the MSTS score was 22.7/30 (range 20-26), while the average lower limb length discrepancy was 3 cm. Patient 1 required a secondary derotation osteotomy of the femur because of abnormal external rotation and a bad result due to the unexplained occurrence of a painful and stiff hip joint. A secondary distal transfer of the greater trochanter was performed in patient 2, and good results based on Hunka et al.'s criteria were achieved. The X-rays of patients 1 and 2 showed signs of bone growth and a major remodeling process; the MRI filling indices were 83 and 67%, respectively. Patient 3 developed an early slipped capital (fibular) epiphysis 1 month postoperatively, which was treated by percutaneous pinning; this early complication led to a bad result with full resorption of the graft. CONCLUSIONS: In contrast to its success in upper limb reconstruction, in this series of three patients with hip articular destruction, articular reconstruction using a vascularized proximal fibula graft was disappointing and led to unsatisfactory results in terms of hip reconstruction. Such a procedure is complex and highly demanding, necessitating extremely intensive post-operative care. An early slipped capital epiphysis can lead to full graft resorption. Consequently, despite important adaptation and remodeling of the graft, the authors do not recommend this procedure at this location.

Kingella kingae: osteoarticular infections of the sternum in children: a report of six cases.

PURPOSE: Kingella kingae is increasingly recognized as a pathogen of osteoarticular infections (OAI) below the age of 2 years. It was reported that bones and joints which are rarely infected by other pathogens were frequently invaded by K. kingae. Based on a series of six cases, we present the typical clinical and paraclinical manifestation of K. kingae infections of the sternum and sterno-manubrial joint. METHODS: A review of the clinical, laboratory, radiological, microbiological, and molecular data of six consecutive children admitted to a paediatric unit for OAI of the sternum was done. RESULTS: Culture alone allowed for the detection of K. kingae as the responsible pathogen in three cases, molecular methods in the three other cases. Clinical and laboratory findings, as well as imaging methods, proved to be useful in the diagnostic process. CONCLUSION: Our findings suggest that infections of the lower sternum and the junction between the manubrium and the xyphoid process are typical, if not pathognomonic, for the organism. A respective diagnostic and therapeutic protocol was established.

Bone stiffness in children: part I. In vivo assessment of the stiffness of femur and tibia in children.

Although there are many publications concerning the mechanical behavior of adult bone, there are few data about mechanical properties of children's bone. In vivo bone stiffness measurement with Orthometer device has been validated and extensively used in adults to assess bone healing after fracture or lengthening. We hypothesized that in vivo stiffness measurement with Orthometer was applicable in children and was correlated with age, height, body weight, and corpulence index. The purpose was to establish baseline stiffness values for femur and tibia in growing children.Sixteen bone measurements (7 femurs and 9 tibias) were obtained during application of an external fixator for leg lengthening in 11 children aged between 5.5 and 16.7 years. A 3-point bending test with an Orthometer was carried out on the intact bone (before osteotomy) under general anesthesia. The anteroposterior stiffness measurement was successful in all children of the series, aged from 5.5 to 16.7 years. A wide variation of femoral and tibial bone stiffness values were observed. The use of a unique value as in adults as the end point of bending stiffness during bone healing process is not possible for children. The anteroposterior bone stiffness was found to have linear correlation with children's height and body weight, but not with age and corpulence indexes. The original data obtained by this study will give a stiffness reference for height and weight and could be useful as reference values for monitoring of healing process after fracture or limb lengthening.

Bone stiffness in children: part II. Objectives criteria for children to assess healing during leg lengthening.

BACKGROUND: The decision when to remove the frame after limb lengthening through standard distraction osteogenesis remains a challenge. Multiple studies have attempted to find objective criteria to assess bone healing after fracture or bone lengthening. However, there is a paucity of such data for the pediatric population. The purpose of this study was to correlate data obtained after dual-energy x-ray absorptiometry (DXA) measurement and bending stiffness in children to find an end-point value for the safe removal of an external fixation device. METHODS: We investigated 16 consecutive children aged between 5.5 and 16.7 years who had 22 lengthenings by callotasis. Twelve femurs and 10 tibiae were lengthened with a monoplane Orthofix external fixator. Fifty simultaneous measurements of bending bone stiffness measured with an Orthometer and DXA scans (bone mineral content [BMC], bone mineral density, volumetric bone mineral density, BMC/1 cm, Area/1 cm, BMC/1 cm, Area) were obtained during healing process. Four femoral fractures were reported after the removal of the external fixation device. Linear regression analysis was used to calculate the squared correlation coefficients for the relation between the DXA scans and the mechanical tests measuring bone stiffness. RESULTS: The bone stiffness measurement of the intact bone was compared with consecutive measurements of the bone stiffness of the regenerate, and it was expressed as a percentage (coefficient). We compared the BMC of the regenerate with the same bone area of the opposite limb. The best correlation was observed for anteroposterior (AP) bone stiffness coefficient and BMC coefficient (R = 0.82). The linear equation was BMC coefficient = 0.5 x AP stiffness coefficient + 30. The end point of 75% of BMC of the regenerate corresponds to 75% of the AP stiffness on DXA scanning; this is the time when we should consider safe removal of the fixator. CONCLUSIONS: Our method of comparing bone stiffness and DXA measurements gives an objective healing end point for every patient irrespective of his or her size. This method could allow noninvasive measurement of the end point and identified at-risk population of children, reducing regenerate fracture after bone lengthening.

Three-dimensional MR imaging in the assessment of physeal growth arrest.

The purpose of this study is to describe an imaging method for identifying and characterising physeal growth arrest following physeal plate aggression. The authors describe the use of three-dimensional MRI performed with fat-suppressed three-dimensional spoiled gradient-recalled echo sequences followed by manual image reconstruction to create a 3D model of the physeal plate. This retrospective series reports the analysis of 33 bony physeal bridges in 28 children (mean age 10.5 years) with the use of fat-suppressed three-dimensional spoiled gradient-recalled echo imaging and 3D reconstructions from the source images. 3D reconstructions were obtained after the outlining was done manually on each source image. Files of all patients were reviewed for clinical data at the time of MRI, type of injury, age at MRI and bone bridge characteristics on reconstructions. Twenty-one (63%) of the 33 bridges were post-traumatic and were mostly situated in the lower extremities (19/21). The distal tibia was involved in 66% (14/21) of the cases. Bridges due to causes other than trauma were located in the lower extremities in 10/12 cases, and the distal femur represented 60% of these cases. Of the 28 patients, five presented with two bridges involving two different growth plates making a total of 33 physeal bone bars. The location and shape of each bridge was accurately identified in each patient, and in post-traumatic cases, 89% of bone bars were of Ogden type III (central) or I (peripheral). Reconstructions were obtained in 15 min and are easy to interpret. Volumes of the physeal bone bridge(s) and of the remaining normal physis were calculated. The bone bridging represented less than 1% to 47% of the total physeal plate volume. The precise shape and location of the bridge can be visualised on the 3D reconstructions. This information is useful in the surgical management of these deformities; as for the eight patients who underwent bone bar resection, an excellent correspondence was found by the treating surgeon between the MRI 3D model and the per-operative findings. Accurate 3D mapping obtained after manual reconstruction can also visualise very small physeal plates and bridges such as in cases of finger physeal disorders. MR imaging with fat-suppressed three-dimensional spoiled gradient-recalled echo sequences can be used to identify patterns of physeal growth arrest. 3D reconstructions can be obtained from the manual outlining of source images to provide an accurate representation of the bony bridge that can be a guide during surgical management.