miR-143 is implicated in growth plate injury by targeting IHH in precartilaginous stem cells.

Precartilaginous stem cells (PCSCs) are able to initiate chondrocyte and bone development. The present study aimed to investigate the role of miR-143 and the underlying mechanisms involved in PCSC proliferation. In a rat growth plate injury model, tissue from the injury site was collected and the expression of miR-143 and its potential targets was determined. PCSCs were isolated from the rabbits' distal epiphyseal growth plate. Cell viability, DNA synthesis, and apoptosis were determined with MTT, BrdU, and flow cytometric analysis, respectively. Real time PCR and western blot were performed to detect the mRNA and protein expression of the indicated genes. Indian hedgehog (IHH) was identified as a target gene for miR-143 with luciferase reporter assay. Decreased expression of miR-143 and increased expression of IHH gene were observed in the growth plate after injury. miR-143 mimics decreased cell viability and DNA synthesis and promoted apoptosis of PCSCs. Conversely, siRNA-mediated inhibition of miR-143 led to increased growth and suppressed apoptosis of PCSCs. Transfection of miR-143 decreased luciferase activity of wild-type IHH but had no effect when the 3'-UTR of IHH was mutated. Furthermore, the effect of miR-143 overexpression was neutralized by overexpression of IHH. Our study showed that miR-143 is involved in growth plate behavior and regulates PCSC growth by targeting IHH, suggesting that miR-143 may serve as a novel target for PCSC-related diseases.

Comparison of mesenchymal stem cell sheets and chondrocyte sheets in a rabbit growth plate injury model

Background/aim: The treatment of posttraumatic deformities and differences in length between the extremities resulting from physeal injury remains controversial. The aims of this study were to compare the efficacy of tissue-engineered, monolayer, and allogeneic mesenchymal stem cell sheets and chondrocyte sheets for physeal arrest treatment and to investigate cell sheet technology as a novel method for cell transplantation in physeal cartilage repair. Materials and methods: A proximal tibial physeal injury was induced in New Zealand rabbits. Allogeneic mesenchymal stem cells (MSCs) and chondrocytes were cultured in temperature-responsive culture dishes and applied to the iatrogenic partial growth plate defects in single-sheet grafts (cell sheets). Treatment efficacy was determined using radiological measurements, as well as histological and immunohistochemical staining. Results: Treatment with MSCs and chondrocytes prevented endochondral ossification in the physeal plate, and bone growth resumed after treatment in both the MSC and chondrocyte cell groups. We found significant differences in radiological evaluations between pre- and posttreatment measurements in both MSC and chondrocyte groups. Transplanted cells were observed in the damaged area in both of the groups, which differentiated in the direction of growth plate cartilage. Conclusion: Our results support the hypothesis that MSC or chondrocyte transplantation using the cell-sheet technique described in the present study aids in the regeneration of cartilage tissue during physeal arrest after growth plate damage.

The heterogeneous management of pediatric ankle traumas: A retrospective descriptive study.

Frequent misdiagnosis of pediatric ankle traumas leads to inappropriate management, which may result in residual pain, instability, slower return to physical activity, and long-term degenerative changes. The purpose of this study was to evaluate the consistency of diagnosis, management, and the treatment of acute lateral pediatric ankle trauma in a tertiary care pediatric hospital. The hypothesis was that the initial diagnosis is often incorrect, and the treatment varies considerably amongst orthopedic surgeons.We conducted a retrospective study of all cases of ankle sprains and Salter-Harris one (SH1) fractures referred to our orthopedic surgery service between May and August 2014. Exclusion criteria included ankle fractures other than SH1 types, and cases where treatment was initially undertaken elsewhere before referral to our service. Primary outcome was the difference between initial and final diagnosis.Among 3047 cases reviewed, 31 matched our inclusion criteria. Initial diagnosis was 20 SH1 fractures, 8 acute ankle sprains, and 3 uncertain, with a change in diagnosis for 48.5% at follow-up.Accurate diagnosis can be difficult in pediatric ankle trauma, with case management and specific treatments varying considerably. This study reinforces the need to evaluate the safety of a general treatment algorithm for all lateral ankle trauma with normal radiographs.Level of evidence III.

Distal Femoral Physeal Fractures.

Physeal fractures of the distal femoral are rare injuries accounting for less than 2% of all physeal injuries, and tend to have a worse prognosis than similar injuries in other locations. This article reviews the evaluation (including imaging), classification, and treatment of these injuries, and discusses their most important complications and their management, including vascular injury and growth arrest.

Isolated Salter-Harris Type III Physeal Fracture of the Distal Ulna.

We describe a case of isolated physeal fracture of ulna distal end in a 13-year-old boy. This fracture type is uncommon, especially Salter-Harris type III of this injury has not been reported. Plain radiographs showed a small vertical fracture line at the ulnar distal end and an enlargement of epiphyseal plate at the base of ulnar styloid process. The present case was successfully managed with conservative treatment because of its minimal displacement.

Distal radius nonunion after epiphyseal plate fracture in a 15 years old young rider.

BACKGROUND AND AIM OF THE WORK: Radius and ulna fractures are the most common long bone fractures in children and adolescents. The majority of these injuries involve the distal metaphyseal portion of the radius associated or not to physeal plate injuries. Because of the high remodelling potential of the distal radius in growing children most injuries heal without complication after closed reduction and immobilization in a long arm cast. Nonunions of closed distal radius fracture are an extremely rare occurrence especially in paediatric population. Methods: In this report, we describe a rare case of distal radius fracture nonunion in a 15-years old male rider treated conservatively with cast immobilization. Eight months later he underwent surgical closed reduction and fixation with kirschner wire and cannulated screw. Results: Follow-up at 2 years showed satisfying radiological and functional outcomes. The patient ultimately returned to ride 3 months following surgery. Conclusions: Nonunion is rarely seen in distal radius fractures in healthy children and adolescents, and there are few studies in the literature. Treatment of the nonunion must be individualized and the results are not entirely predictable.

Treatment of rabbit growth plate injuries with oriented ECM scaffold and autologous BMSCs.

Tissue-engineered technology has provided a promising method for the repair of growth plate injuries using biocompatible and biodegradable scaffolds and appropriate cells. The aim of this study was to fabricate oriented ECM scaffolds to imitate the material and structure of a natural growth plate and to investigate whether BMSCs in a scaffold could prevent the formation of bone bridges in an injured growth plate. We developed a natural, acellular and oriented scaffold derived from a growth plate. The oriented scaffold was fabricated using new freeze-drying technology and by cross-linking the microfilaments in the growth plate. From histological examination, the scaffold contained most of the ECM components including GAG and collagen II without cell DNA fragments, and SEM revealed that oriented scaffold had a uniform aperture in the transverse plane and columnar structure in length plane. Cytotoxicity testing with MTT showed no cytotoxic effect of the scaffold extracts on BMSCs. Autogenous BMSCs in oriented scaffolds promoted the regeneration of neogenetic growth plate when repairing an injured growth plate and prevent the formation of bone bridges to reduce the angular deformity and length discrepancy in the proximal tibia in rabbits. The well-characterized ECM-derived oriented growth plate scaffold shows potential for the repair of injured growth plates in young rabbits.