Magnetic Resonance Imaging Manifestations of Annular Ligament Injuries in Children With Monteggia Fractures.

BACKGROUND: Magnetic resonance imaging (MRI) is commonly performed in children with elbow injuries to visualize soft tissues such as the annular ligament. Herein, we investigated the MRI manifestations of annular ligament injuries in children with Monteggia fractures following attempted closed reduction. METHODS: The clinical and imaging data of 88 children with acute Monteggia fractures treated at our hospital between 2015 and 2019 were analyzed. Clinically and radiographically, 67 patients achieved radiologic reduction of the radial head at the time of MRI, whereas 21 patients had a failed closed reduction. Annular ligament injury and superior radioulnar joint congruency were analyzed qualitatively, and the maximum superior radioulnar joint gap distance was measured. RESULTS: MRI manifestations of annular ligament injury were primarily characterized as varying degrees of annular ligament displacement, as follows: I degree (10 patients), the annular ligament encircled the radial head without displacement; II degree (5 patients), the annular ligament was partially displaced but visibly encircled the radial head at the level of the radial notch; and III degree (73 patients), the annular ligament was completely displaced. In 15 patients with I and II degrees annular ligament injuries, the annular ligament encircled the radial head (maximum superior radioulnar joint gap distance, 1.2±0.3 mm), showing good congruency of the superior radioulnar joint. In 73 patients with III degree annular ligament injury, the annular ligament was displaced and did not encircle the radial head (maximum superior radioulnar joint gap distance, 3.3±2.7 mm; P <0.05), showing good congruency of the superior radioulnar joint in 25 of 73 patients, and significantly poor congruency in 48 of 73 patients ( P <0.05). CONCLUSIONS: Annular ligament injuries in children with Monteggia fractures exhibit different degrees of displacement of the annular ligament. In I and II degree annular ligament injuries, the annular ligament still encircles the radial head. In III degree annular ligament injuries, the annular ligament is displaced away and is no longer around the radial head. Without the annular ligament restraining the radial head, the superior radioulnar joint is more likely to exhibit poor congruency and increased gap distance. LEVEL OF EVIDENCE: Level II.

Application of Digital Orthopedic Technology in Orthopedic Trauma.

In order to solve the limitation of auxiliary treatment means in the process of orthopedic trauma surgery, and further improve the effective integration of orthopedic trauma clinical surgery and computer technology, a new orthopedic trauma auxiliary treatment means based on digital orthopedic technology was proposed with the aid of virtual digital technology. The method builds a 3D model of fracture fragments through 3D orthopedic modeling and obtains a high-quality 3D model through processing. Later clinical tests verify the feasibility of this auxiliary treatment method. The test results show that the precision of the 3D reconstruction model based on custom option fitting is higher than that based on optimal option fitting, and the precision difference is within 0.2%. This result also indicates that the 3D model obtained by 3D reconstruction has higher accuracy. The results show that three-dimensional finite element modeling technology can accurately simulate the stress of the spine of orthopedic patients and can reduce the incidence of complications through preoperative diagnosis, curative effect prediction, and trauma surgery, which has a good aid for postoperative recovery.

Robot-assisted treatment of unstable pelvic fractures with a percutaneous iliac lumbar double rod fixation combined with a percutaneous pelvic anterior ring INFIX fixation.

OBJECTIVE: To investigate the clinical effect of robot-assisted treatment of unstable pelvic fractures through a percutaneous iliac lumbar double rod fixation combined with a percutaneous pelvic anterior ring INFIX (internal fixator) fixation. METHODS: This was a retrospective analysis of 17 cases of unstable anterior and posterior pelvic ring fractures treated between April 2016 and October 2018 by the third Ti-robot system produced in China. The posterior ring was supported with an iliac lumbar double rod fixation and the anterior ring with an INFIX fixation. Operation time and peri-operative bleeding were recorded. The reduction of pelvic fracture displacement was evaluated by Matta score, the post-operative results were evaluated according to Majeed score, and the complications were recorded. RESULTS: Twelve males and five females, aged 21-71 years (mean 40.1 ± 3.8 years) were followed up for three to 12 months, (median 6.7 months). Tile typing showed seven B1 type, two B2 type, and eight C1 type cases. Operation time was 90-160 minutes (mean 112.9 ± 16.8 minutes), bleeding was 80-150 mL (mean 105.9 ± 20.6 mL). X-ray three to five  days after operation was evaluated by Matta score as excellent in 15 and good in two cases. Majeed score at last follow-up was 85-98 points, excellent in 17 cases. Two cases of lower extremity deep vein thrombosis received an inferior vena cava filter. The filters were removed after two  weeks. One case showed incision fat liquefaction healing and the wound healed three  weeks after surgery. CONCLUSION: Orthopedic robot-assisted treatment of unstable pelvic fractures by a percutaneous iliac lumbar double rod fixation and a percutaneous pelvic anterior ring INFIX fixator was minimally invasive and feasible. A prospective study is needed.

Osteogenic potency of dedifferentiated fat cells isolated from elderly people with osteoporosis.

Mature adipocytes are the major cell type in adipose tissue. This study aimed to explore the osteogenic potency of dedifferentiated fat cells obtained from osteoporotic patients (opDFATs) in vitro and in vivo. Mature adipocytes and adipose-derived stem cells (opASCs) were harvested from subcutaneous adipose tissue. Mature adipocytes were dedifferentiated to produce opDFATs by the ceiling culture method. OpDFATs were osteogenically induced in vitro with opASCs as a control. Cell growth, alkaline phosphatase (ALPase) activity and cell mineralization were determined, and expression levels of osteogenesis-specific genes (collagen I, osteocalcin and bone sialoprotein) were analyzed using quantitative reverse transcription polymerase chain reaction. After 14 days, the opDFATs were combined with a poly(lactide-co-glycolide)-ß-tricalcium phosphate porous scaffold after being suspended in collagen I gel and implanted into nude mice for 4 weeks prior to histological analysis. Unilocular lipid droplets in mature adipocytes gradually split into smaller droplets and disappeared from the cytoplasm. Mature adipocytes dedifferentiated to opDFATs and cell morphology changed from spherical to elongated. High levels of ALPase and cell mineralization were observed in opDFATs by staining. No significant differences were found between the growth curves, ALPase activity, cell mineralization and expression levels of osteogenesis-specific genes between opDFATS and opASCs. After implantation for 4 weeks, new bone tissue was observed histologically in the opDFATs-based biocomposite. OpDFATs are implicated as a novel type of seed cell for bone tissue engineering based on their osteogenic potency and higher abundance in adipose tissue compared with opASCs.

Sirt2 suppresses inflammatory responses in collagen-induced arthritis.

Arthritis is a common autoimmune disease that is associated with progressive disability, systemic complications and early death. However, the underling mechanisms of arthritis are still unclear. Sirtuins are a NAD(+)-dependent class III deacetylase family, and regulate cellular stress, inflammation, genomic stability, carcinogenesis, and energy metabolism. Among the sirtuin family members, Sirt1 and Sirt6 are critically involved in the development of arthritis. It remains unknown whether other sirtuin family members participate in arthritis. Here in this study, we demonstrate that Sirt2 inhibits collagen-induced arthritis (CIA) using in vivo and in vitro evidence. The protein and mRNA levels of Sirt2 significantly decreased in joint tissues of mice with CIA. When immunized with collagen, Sirt2-KO mice showed aggravated severity of arthritis based on clinical scores, hind paw thickness, and radiological and molecular findings. Mechanically, Sirt2 deacetylated p65 subunit of nuclear factor-kappa B (NF-κB) at lysine 310, resulting in reduced expression of NF-κB-dependent genes, including interleukin 1ß (IL-1ß), IL-6, monocyte chemoattractant protein 1(MCP-1), RANTES, matrix metalloproteinase 9 (MMP-9) and MMP-13. Importantly, our rescue experiment showed that Sirt2 re-expression abated the severity of arthritis in Sirt2-KO mice. Those findings strongly indicate Sirt2 as a considerably inhibitor of the development of arthritis.

[Comparison of stability of sacroiliac screws in the treatment of bilateral sacral fractures in a finite element model].

OBJECTIVE: To compare the stability of sacroiliac screws fixation for the treatment of bilateral vertical sacral fractures to provide reference for clinic application. METHODS: A finite element model of Tile C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. The bilateral sacral fractures were fixed with sacroiliac screws in 4 types of models respectively: two bidirectional sacroiliac screws fixation in the S1 segment, two bidirectional sacroiliac screws fixation in the S2 segment, one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment, two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively. By the ABAQUS 6.9.1 software, in the case of standing on both feet, 600 N vertical load was imitated to be imposed to the superior surface of the sacrum and downward translation and backward angle displacement of the middle part of the sacral superior surface and everted angle displacement of the top of iliac bones were extracted for analysis. The stability of sacroiliac screws fixation was compared according to the principle of the better stability the smaller displacement. RESULTS: The stability of 2 bidirectional sacroiliac screws fixation in S1 and S2 segments respectively was markedly superior to that of 2 bidirectional sacroiliac screws fixation in S1 or S2 segment and was also markedly superior to that of one sacroiliac screw fixation in S1 segment and one sacroiliac screw fixation in S2 segment. The vertical and everted stability (the downward translation: 0.531 mm; the everted angle displacement: 0.156° (left side), 0.163° (right side)) of sacroiliac screws fixation in two bidirectional sacroiliac screws fixation in the S2 segment was superior to that of two bidirectional sacroiliac screws fixation in the S1 segment (the downward translation: 0.673 mm; the everted angle displacement: 0.200° (left side), 0.232° (right side)). The rotational stability of two bidirectional sacroiliac screws fixation in the S1 segment (the backward angle displacement: 0.269°) was superior to that of two bidirectional sacroiliac screws fixation in the S2 segment (the backward angle displacement: 0.287°). Moreover, the rotational stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was inferior to that of two bidirectional sacroiliac screws fixation in the S1 segment or two bidirectional sacroiliac screws fixation in the S2 segment, and the vertical and everted stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was between that of two bidirectional sacroiliac screws fixation in the S1 segment and two bidirectional sacroiliac screws fixation in the S2 segment. CONCLUSIONS: Two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively is recommended to be utilized for fixing bilateral sacral fractures of Tile C pelvic ring injury as far as possible. It is suggested to choose sacral segments in which sacroiliac screws fixed according to vertical, rotational and everted stability degree of sacral fractures.