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

Bone lengthening using fitbone(r) motorized intramedullary nail: the first experience in France.

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

Arthroscopic treatment of intercondylar eminence fractures with intraepiphyseal screws in children and adolescents

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

Influence of fluid-flow direction on effective permeability of the vertebral end plate: an analytical model

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

MRI of acute osteomyelitis in long bones of children: pathophysiology study.

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

Osteochondritis dissecans of the knee

Osteochondritis dissecans (OCD) of the knee is an idiopathic, focal, subchondral-bone abnormality that can cause instability or detachment of a bone fragment and overlying articular cartilage, with subsequent progression to osteoarthritis. The diagnosis is usually made during adolescence. Mechanical factors play a major role in the pathophysiology of OCD. When the radiographic diagnosis is made early in a patient with open physes, healing can often be obtained simply by restricting sports activities. The degree of lesion instability can be assessed by magnetic resonance imaging. When the lesion remains unstable and the pain persists despite a period of rest, surgery is indicated. Arthroscopic exploration is always the first step. Drilling of the lesion produces excellent outcomes if the lesion is stable. Unstable lesions require fixation and, in some cases, bone grafting. Defects must be filled, depending on their surface area. Although many surgical techniques are available, the therapeutic indications are now standardized

Triple osteotomy of the pelvis for Legg-Calve-Perthes disease: a mean fifteen year follow-up.

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

Correlations between effective permeability and marrow contact channels surface of vertebral endplates

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 mu m) 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

Influence of growth modulation on the effective permeability of the vertebral end plate. A porcine experimental scoliosis model

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 degrees right thoracic curve. 44 degrees lordosis and 21 degrees 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

Whole-exome sequencing in osteosarcoma reveals important heterogeneity of genetic alterations

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 managemen