Finite Element Analysis of Mechanical Characteristics of Internal Fixation for Treatment of Proximal Femoral Osteolytic Lesions in Children.

OBJECTIVES: Clinically, it is very difficult to prevent pathological fracture caused by high recurrence rate of osteolytic disease of proximal femur in children. At present, there is no consensus in clinical studies of which internal fixation method can significantly reduce the probability of recurrence of pathological fracture. The study aims to research the mechanical properties of different internal fixations in the treatment of osteolytic lesions of proximal femur in children by finite element analysis, and to find out the optimal treatment. METHODS: Based on finite element analysis, the osteolytic disease models of the femoral neck and intertrochanter in a child (8-year-old, boy) were established respectively, and different internal fixation models (plate and titanium elastic intramedullary nails, TENs) were assembled. For the osteolytic lesion of the femoral neck: model A1 was assembled with a plate; model A2 with two TENs crossing the physis; model A3 with two TENs without crossing the physis. And for pertrochanteric osteolytic lesion: model B1 was assembled with a plate, model B2 with two TENs crossing the physis and model B3 with two TENs without crossing the physis. The Eccentric bearing load, torsional restraintal restraint of calcar femorale and composite load were analyzed for each models. RESULTS: When the yield strain of each model is reached, the stress concentration points are located in the proximal and distal femoral calcar. In the model of femoral neck lesions, the failure load of model A1 and model A2 are the same (1250 N), and the failure load of model A3 (980 N) is significantly lower than that of the former two; in the model of intertrochanteric lesions, the failure load of model B2 is the largest (1350 N), and the failure load of model B1 (1220 N) is lower than that of model B3 (1260 N), but both are smaller than that of model B2. CONCLUSION: Through finite element analysis, TENs through the epiphyseal plate, is found to be the better internal fixation method for femoral neck lesions and intertrochanteric lesions under two different working conditions. The results of clinical correlation study provide new biomechanical information for orthopedic doctors to consider different treatment options for osteolytic lesions of proximal femur.

Clinical Efficacy of Minimally Invasive Elastic Stable Intramedullary Nailing for Limb Long Bone Fractures in Children.

OBJECTIVE: The aim of the present paper was to investigate the clinical efficacy of minimally invasive elastic stable intramedullary nailing (ESIN) for long bone fractures in children. METHODS: A total of 350 children with limb fractures from June 2012 to June 2018 were recruited and randomized into two groups: an ESIN group (n = 175) treated with elastic stable intramedullary nailing, and an MPIF group (n = 175), treated with metal plate internal fixation. Both groups received the same physical examination and routine medication. Operation related indexes, clinical efficacy, complications, and postoperative quality of life scores were analyzed and compared. RESULTS: The operation time, intraoperative blood loss, hospitalization time, and fracture healing time in the ESIN group were 43.74 ± 4.96 min, 8.14 ± 1.34 mL, 5.97 ± 1.88 days, and 55.89 ± 5.61 days, respectively, which were all significantly less than those in the MPIF group (all P < 0.001). In terms of common complications after limb fracture treatment, there were 6 cases of osteomyelitis, 5 cases of skin irritation response, and 7 cases of inflammatory granuloma in the MPIF group. There were 2 cases of skin irritation response and 5 cases of inflammatory granuloma in the ESIN group. The incidence of postoperative complications in the ESIN group was 4.00%, which was significantly lower than that in MPIF group (10.29%) (P < 0.05). The effective rate for recovery condition in the ESIN group (93.71%) was significantly higher than that in the MPIF group (P < 0.001). The quality of life scores after treatment in both groups were improved, while the score in the ESIN group was significantly higher than that in the MPIF group (79.43%) (P < 0.001). The postoperative satisfaction rate in the ESIN group (94.29%) was significantly higher than that in the MPIF group (86.29%) (P < 0.05). The quality of life scores after treatment in both groups were improved, while the score in the ESIN group was significantly higher than that in the MPIF group (P < 0.001). The postoperative satisfaction rate and the acceptance rate for adjacent joint function in the ESIN group (100%) were significantly higher than those in the MPIF group (92.00%) (P < 0.0001). CONCLUSION: Elastic stable intramedullary nailing is a minimally invasive procedure for long bone fractures in children. It can effectively improve the operation-related indicators and postoperative quality of life and reduce the incidence of complications.

Novel deletion and 2397 G>T mutations of the EXT1 gene identified in two Chinese pedigrees with hereditary multiple exostoses using exon sequencing.

BACKGROUND: Hereditary multiple exostoses (HME), a rare genetic pediatric disorder, has a peculiar pathogenic mechanism. The results of previous studies have shown that HME is associated with mutations of the EXT1 and EXT2 genes at a molecular genetics level. In our study, two families who received therapy in the Department of Orthopedics of Shanghai Children's Hospital between June, 2017 and November, 2018 were recruited, and a mutational analysis of the EXT1 genes was conducted to further elucidating the relationship between HME and EXT1. METHODS: Venous blood samples were collected from individuals with HME and their families. Exon sequencing and RT-PCR were performed to comprehensively analyze 11 exons of the EXT1 gene. RESULTS: The deletion of exon 7 and the 2397 G>T mutation in exon 7 caused deletion mutation and nonsense mutation only in the HME patients. The mutations in exon 7 were tested and verified by Sanger sequencing. RT-PCR showed that the mRNA expression of EXT1 was significantly decreased in the mutation samples compared with the normal samples, which exerted a great influence on the function of EXT1. CONCLUSIONS: This study identified new mutation sites for the pathogenesis of HME and further clarified the relationship between HME and EXT1.

Prevalence and Clinical Significance of Occult Fractures in the Extremities in Children.

Objective: Diagnosis of occult fractures by initial plain radiographs remains challenging in children in the emergency room. This study was to assess the prevalence and distribution of occult fracture in children with acute extremities injuries (AEI) and clinical suspicion of fracture. Methods: We conducted a retrospective study to review the medical records of all pediatric patients with AEI in the orthopedic emergency room from January 1, 2017, to December 31, 2019. For patients with concerning history and physical examination but negative initial radiographs, we conducted the following three diagnostic strategies according to the choic of children's parents: immediate MRI scanning, [2] immediate CT scanning, or [3] empiric cast immobilization with orthopedic follow-up radiographs at 2 weeks post-injury (late radiographs). Prevalence and distribution of occult fracture were recorded. Results: A total of 43,560 pediatric patients meet the inclusion criteria. A total of 4,916 fractures of the extremities were confirmed by initial plain radiographs, and 550 occult fractures were confirmed by immediate MRI, immediate CT, or late radiographs. The prevalence of occult fracture in the extremities was 10.1% (550/5,466). Supracondylar fractures were the most prevalent (2,325/5,466, 42.5%) but had the lowest rate of occult fractures (117/2,325, 5.0%). The highest rate of occult fracture was distal epiphyseal fracture of the tibia and fibula (49/145, 33.8%), but these had a relatively lower prevalence of fractures (145/5,466, 2.65%). Conclusions: We should be aware of the relative high prevalence of occult fractures in the extremities in children, especially when the injured site is in the high incidence area of occult fracture such as ankle.

Auxiliary Kirschner wire technique in the closed reduction of children with Gartland Type III Supracondylar humerus fractures.

This study aimed to investigate the effect of auxiliary Kirschner wire (K-wire) technique in the closed reduction of children with Gartland type III supracondylar humerus fractures by comparing with manual reduction alone.Retrospective analysis was performed on the clinical data of 68 cases of supracondylar humerus fractures. Thirty-six patients received closed reduction and percutaneous fixation with auxiliary K-wire technique (group A). Thirty-two patients received conventional manual reduction and percutaneous pin fixation (Group B).In group A, the average operation time was 20.5 ±â€Š8.5 minutes, the average frequency of intraoperative radiographic observations was 4.3 ±â€Š1.1, the average fracture healing time was 6.2 ±â€Š1.8 weeks, and the complication rate was 3/36, 8.3%. The mean operation time was 36.1 ±â€Š10.2 minutes, the average frequency of intraoperative radiography was 8.9 + 1.7 times, the average fracture healing time was (6.1 ±â€Š1.6) weeks, and the complication rate was 2/32, 6.3%. The operation time in group A was significantly shorter than that in group B. The difference between the 2 groups was statistically significant (P = .012). The frequency of radiography in group A was significantly less than that in group B (P = .001).Compared with manual reduction, auxiliary K-wire technology can significantly shorten the operation time, reduce the radiant quantity of the surgeon, improve the efficiency of closed reduction of children with Gartland type III supracondylar humerus fractures, and reduce the risk of developing postoperative complications. And meanwhile, there is no significant effect on the imaging and functional outcomes of affected extremities, which is worthy of respect.