Impact of foot progression angle on spatiotemporal and plantar loading pattern in intoeing children during gait.

Intoeing in children is a common parental concern, but our understanding of the impact of foot progression angle (FPA) in these children leaves remains limited. This study examines the relationship between FPA and plantar loading pattern, as well as gait symmetry in children with intoeing. The sample included 30 children with intoeing caused by internal tibial torsion, uniformly divided into three groups: unilateral intoeing, bilateral mild intoeing, and bilateral mild-moderate intoeing. The relationship between FPA and plantar loading pattern, and gait symmetry within and among groups were assessed using dynamic pedobarographic and spatiotemporal data. Results indicated a significant correlation between FPA and peak pressure, maximum force, and plantar impulse in the medial and central forefoot, and also the medial and lateral heel zones for both bilateral intoeing groups. Significant differences were observed only in subdivided stance phase, including loading response, single support, and pre-swing phases, between the unilateral intoeing and bilateral mild intoeing groups. These findings suggest that FPA significantly affects the forefoot and heel zones, potentially increasing the load on the support structures and leading to transverse arch deformation. While children with intoeing demonstrate a dynamic self-adjustment capability to maintain gait symmetry, this ability begins to falter as intoeing becomes more pronounced.

Corrigendum to "3D-printed tri-element-doped hydroxyapatite/ polycaprolactone composite scaffolds with antibacterial potential for osteosarcoma therapy and bone regeneration" [Bioact. Mater. 31 (January 2024) 18-37].

[This corrects the article DOI: 10.1016/j.bioactmat.2023.07.004.].

3D-printed tri-element-doped hydroxyapatite/ polycaprolactone composite scaffolds with antibacterial potential for osteosarcoma therapy and bone regeneration.

The resection of malignant osteosarcoma often results in large segmental bone defects, and the residual cells can facilitate recurrence. Consequently, the treatment of osteosarcoma is a major challenge in clinical practice. The ideal goal of treatment for osteosarcoma is to eliminate it thoroughly, and repair the resultant bone defects as well as avoid bacterial infections. Herein, we fabricated a selenium/strontium/zinc-doped hydroxyapatite (Se/Sr/Zn-HA) powder by hydrothermal method, and then employed it with polycaprolactone (PCL) as ink to construct composite scaffolds through 3D printing, and finally introduced them in bone defect repair induced by malignant osteosarcoma. The resultant composite scaffolds integrated multiple functions involving anti-tumor, osteogenic, and antibacterial potentials, mainly attributed to the anti-tumor effects of SeO32-, osteogenic effects of Sr2+ and Zn2+, and antibacterial effects of SeO32- and Zn2+. In vitro studies confirmed that Se/Sr/Zn-HA leaching solution could induce apoptosis of osteosarcoma cells, differentiation of MSCs, and proliferation of MC3T3-E1 while showing excellent antibacterial properties. In vivo tests demonstrated that Se/Sr/Zn-HA could significantly suppress tumors after 8 days of injection, and the Se/Sr/Zn-HA-PCLs scaffold repaired femoral defects effectively after 3 months of implantation. Summarily, the Se/Sr/Zn-HA-PCLs composite scaffolds developed in this study were effective for tumor treatment, bone defect repair, and post-operative anti-infection, which provided a great potential to be a facile therapeutic material for osteosarcoma resection.

Tissue engineering in growth plate cartilage regeneration: Mechanisms to therapeutic strategies.

The repair of growth plate injuries is a highly complex process that involves precise spatiotemporal regulation of multiple cell types. While significant progress has been made in understanding the pathological mechanisms underlying growth plate injuries, effectively regulating this process to regenerate the injured growth plate cartilage remains a challenge. Tissue engineering technology has emerged as a promising therapeutic approach for achieving tissue regeneration through the use of functional biological materials, seed cells and biological factors, and it is now widely applied to the regeneration of bone and cartilage. However, due to the unique structure and function of growth plate cartilage, distinct strategies are required for effective regeneration. Thus, this review provides an overview of current research on the application of tissue engineering to promote growth plate regeneration. It aims to elucidates the underlying mechanisms by which tissue engineering promotes growth plate regeneration and to provide novel insights and therapeutic strategies for future research on the regeneration of growth plate.

Risk factor analysis for tibial tubercle avulsion fractures in children.

PURPOSE: Tibial tubercle avulsion fractures (TTAFs) are rare in children, particularly bilateral TTAFs. This study aimed to elucidate the associating factors of TTAF, and compare the risk factor profiles of unilateral and bilateral injuries, thus provide clinical theoretical basis for reducing the occurrence of TTAFs. METHODS: TTAF paediatric patients who were hospitalized between April 2017 and November 2022 were retrospectively analysed. Children who presented for physical examination during the same period were randomly selected, and were age- and sex-matched as controls. A subgroup analysis based on endocrine function was also performed. A risk factor analysis for bilateral TTAF was performed as well. Data were collected via medical records and a questionnaire. All variables were assessed for association with TTAF using univariate and multiple logistic regression analyses. RESULTS: A total of 64 TTAF patients and controls were respectively included. Multivariate analysis demonstrated BMI (P = 0.000，OR = 3.172), glucose (P = 0.016，OR = 20.878), and calcium (P = 0.034，OR = 0.000) as independent associating factors of TTAF. Subgroup analysis showed significant differences in oestradiol (P = 0.014), progesterone (P = 0.006) and insulin levels (P = 0.005) between the TTAF and control groups. Bilateral TTAF was found to significantly associate with a history of knee joint pain (P = 0.026). CONCLUSION: High BMI, hyperglycaemia, and low calcium levels were found as independent risk factors for TTAF in children. In addition, decreased oestradiol, elevated progesterone, and insulin resistance were identified as potential risk factors for TTAF. A history of knee pain may be suggestive of bilateral TTAF.

A Novel Method for Treating Distal Radius Diaphyseal Metaphyseal Junction Fracture in Children.

BACKGROUND The treatment of distal radius diaphyseal metaphyseal junction (DMJ) fracture in children is a clinical problem; several treatments are available, but none are very effective. Therefore, this study aimed to report a novel method for treating this fracture using limited open reduction and transepiphyseal intramedullary fixation with Kirschner wire. MATERIAL AND METHODS From January 2018 to December 2019, a total of 15 children (13 boys and 2 girls) with distal radius DMJ fractures with a mean age of 10 years (range: 6-14 years) were included in the study. The operation time, incision length, and X-ray radiation exposure were precisely recorded. All children were followed up regularly. At the final follow-up, clinical outcomes were evaluated according to Price criteria, and complications were recorded. RESULTS The mean operation time of the 15 children was 21.4 min, and the mean incision length was 1.9 cm. The intraoperative X-ray was performed 3.7 times on average. The mean radiographic union of fracture was 4.7 weeks, and the mean time to remove the Kirschner wire was 4.8 weeks for radial instrumentation and 4.7 months for ulnar instrumentation. According to the Price grading evaluation system, clinical outcome was excellent in 14 cases and good in 1 case. Moreover, there were no major complications related to loss of reduction, malunion, nonunion, and physeal arrest of the distal radius. CONCLUSIONS Limited open reduction and transepiphyseal intramedullary fixation with Kirschner wire are effective for treating distal radius DMJ fracture in children, which has the advantages of simple surgical procedures, short operation time, small incision, and less radiation exposure, making it an excellent choice for treating this fracture.

3D bioprinted hydrogel/polymer scaffold with factor delivery and mechanical support for growth plate injury repair.

Introduction: Growth plate injury is a significant challenge in clinical practice, as it could severely affect the limb development of children, leading to limb deformity. Tissue engineering and 3D bioprinting technology have great potential in the repair and regeneration of injured growth plate, but there are still challenges associated with achieving successful repair outcomes. Methods: In this study, GelMA hydrogel containing PLGA microspheres loaded with chondrogenic factor PTH(1-34) was combined with BMSCs and Polycaprolactone (PCL) to develop the PTH(1-34)@PLGA/BMSCs/GelMA-PCL scaffold using bio-3D printing technology. Results: The scaffold exhibited a three-dimensional interconnected porous network structure, good mechanical properties, biocompatibility, and was suitable for cellchondrogenic differentiation. And a rabbit model of growth plate injury was appliedto validate the effect of scaffold on the repair of injured growth plate. The resultsshowed that the scaffold was more effective than injectable hydrogel in promotingcartilage regeneration and reducing bone bridge formation. Moreover, the addition ofPCL to the scaffold provided good mechanical support, significantly reducing limbdeformities after growth plate injury compared with directly injected hydrogel. Discussion: Accordingly, our study demonstrates the feasibility of using 3D printed scaffolds for treating growth plate injuries and could offer a new strategy for the development of growth plate tissue engineering therapy.

Injectable hydrogel loaded with bilayer microspheres to inhibit angiogenesis and promote cartilage regeneration for repairing growth plate injury.

Introduction: The repair and regeneration of growth plate injuries using tissue engineering techniques remains a challenge due to large bone bridge formation and low chondrogenic efficiency. Methods: In this study, a bilayer drug-loaded microspheres was developed that contains the vascular endothelial growth factor (VEGF) inhibitor, Bevacizumab, on the outer layer and insulin-like growth factor-1 (IGF-1), a cartilage repair factor, on the inner layer. The microspheres were then combined with bone marrow mesenchymal stem cells (BMSCs) in the gelatin methacryloyl (GelMA) hydrogel to create a composite hydrogel with good injectability and biocompatibility. Results: The in vitro drug-release profile of bilayer microspheres showed a sequential release, with Bevacizumab released first followed by IGF-1. And this hydrogel simultaneously inhibited angiogenesis and promoted cartilage regeneration. Finally, in vivo studies indicated that the composite hydrogel reduced bone bridge formation and improved cartilage regeneration in the rabbit model of proximal tibial growth plate injury. Conclusion: This bilayer microsphere-based composite hydrogel with sequential controlled release of Bevacizumab and IGF-1 has promising potential for growth plate injury repair.

Risk factors for femoral overgrowth after femoral shortening osteotomy in children with developmental dysplasia of the hip.

Objective: Developmental dysplasia of the hip (DDH) refers to a series of deformity of acetabulum and proximal femur and abnormal relationship between them, it represents the most common hip disease in children. Overgrowth and limb length discrepancy (LLD) was common complication in children undergoing femoral shortening osteotomy. Therefore, the purpose of this study was to explore the risk factors of overgrowth after femoral shortening osteotomy in children with DDH. Methods: We included 52 children with unilateral DDH who underwent pelvic osteotomy combined with femoral shortening osteotomy between January 2016 and April 2018, including seven males (six left and one right hip) and 45 females (33 left and 12 right hips) with an average age of 5.00 ± 2.48 years, and an average follow-up time of 45.85 ± 6.22 months. The amount of overgrowth and limb length discrepancies (LLDs) were calculated. The risk factors of femoral overgrowth ≥1 cm and LLD ≥ 1 cm were analyzed. Results: There were statistical differences in age (p < 0.001) and operation duration (p = 0.010) between the two groups with femoral overgrowth <1 cm and ≥1 cm. There was a statistical difference in operation duration (p < 0.001) between the two groups. Age (p < 0.001) was an independent influencing factor of femoral overgrowth in children with unilateral DDH after pelvic osteotomy and femoral shortening osteotomy, and a risk factor (p = 0.008) of LLD in these children. Conclusion: The overgrowth and LLD of children with developmental dislocation of hip after pelvic osteotomy and femoral shortening osteotomy are significantly related to age. There was no significant difference between different pelvic osteotomies for femoral overgrowth in children. Therefore, surgeons should consider the possibility of LLD after femoral shortening osteotomy in children of a young age.

Modified radial tongue-shaped flap following stepwise surgical release for Benson type I camptodactyly of the 5th digit.

To investigate the outcomes of the modified radial tongue-shaped flap following stepwise surgery release for treating Benson type I camptodactyly of the 5th digit. A retrospective analysis involving patients with Benson type I camptodactyly of the 5th digit was performed. A total of 8 patients with 12 affected digits were included. Extent of surgical release depended on the degree of soft tissue contracture. Skin release, subcutaneous fascial release, and flexor digitorum superficialis tenotomy were performed in all 12 digits, sliding volar plate release in 2 digits, and intrinsic tendon transfer in 1 digit. The mean total passive motion of proximal interphalangeal joint significantly increased from 32.5° ± 16° to 86.3° ± 20.4°, while mean total active motion significantly increased from 22° ± 10.5° to 73.8° ± 27.5° (P < 0.05). Treatment outcomes were excellent in 6 patients, good in 3, moderate in 2, and poor in 1. Scar hyperplasia occurred in 1 patient. The radial tongue-shaped flap allowed for full coverage of the volar skin defect, and was considered aesthetically favorable. In addition, the stepwise surgical approach not only achieved good curative effects, but also allowed for individualization of treatment.

A New Method for Modeling Rabbit Growth Plate Injury for the Study of Tissue Engineering Scaffolds.

Establishing a suitable animal model of growth plate injury is necessary to evaluate the effect of tissue engineering scaffolds on repairing the injured growth plate. However, the currently used animal models have limitations. Therefore in this study, we reported and evaluated a new modeling method termed the longitudinal disruption method, which is to make a longitudinal defect in the region of growth plate. To compare this new method with the traditional transverse disruption method, we constructed the models by both methods, respectively. To observe whether bone bridges were formed, histological sections were analyzed by hematoxylin-eosin (HE) and Masson staining at 3 weeks after modeling. The HE and Masson staining results showed the formation of bone bridges in both groups, implying that the two methods successfully injured the growth plate. However, it was unclear whether the exact injury to growth plate caused by both methods was consistent. Therefore, to evaluate the accuracy and precision of modeling method, the X-ray and micro-computed tomography (CT) were performed immediately after modeling. The percentages of accurate defect position in the longitudinal and transverse modeling groups were 88.89% and 55.56%, respectively. The micro-CT results revealed irregularly shaped defect cross sections in the transverse modeling group, whereas the defects in the longitudinal modeling group had regular shapes. The mean defect areas were 10.06 ± 0.86 and 12.30 ± 2.13 mm2 in the longitudinal and transverse modeling groups, respectively, while the difference between the actual area and the expected area were -1.94 ± 0.86 and -7.70 ± 2.13 mm2, respectively, showing the high precision of this new method. Altogether, we successfully demonstrated a new method for establishing a rabbit model of growth plate injury, which provides a simple and rapid modeling process, good modeling effect, high modeling accuracy, and convenient scaffold implantation. The new method provides an effective animal model for tissue engineering research on the repair and regeneration of injured growth plate. Impact Statement In recent years, an increasing number of studies have used tissue engineering scaffolds in the repair and regeneration of growth plate. However, the currently used animal models have certain limitations in the study of tissue engineering scaffold for growth plate. In this study, a new method is presented to establish a rabbit model of growth plate injury. This method is characterized by simple and rapid modeling process, good modeling effect, high modeling accuracy, and convenient scaffold implantation, which is suitable for the study of the repair effects of tissue engineering scaffolds. Altogether, this method provides an effective animal model for tissue engineering research on growth plate and facilitates the development of tissue engineering research on the repair and regeneration of injured growth plate.