Newly designed plate for the treatment of posterolateral tibial plateau fractures: a finite element analysis.

BACKGROUND: This study investigated the biomechanical properties of a new plate used for the treatment of posterolateral tibial plateau fractures using finite element analysis. METHODS: The study groups were as follows: group PM, model of the new plate with posteromedial tibial plateau fracture; group PL, model of the new plate with posterolateral tibial plateau fracture; and group PC, model of the new plate with posterior tibial plateau fracture. We used two loading modes: uniform loading on the entire plateau, and loading on the posterior plateau. Data such as the displacement of the fracture and distribution of stress on the new plate and screws were recorded and analyzed. RESULTS: When the whole plateau was loaded, the displacement of fractures in groups PM, PL, and PC were 0.273, 0.114, and 0.265 mm, respectively. The maximum stresses on the plates in groups PM, PL, and PC were 118.131 MPa, 44.191 MPa, and 115.433 MPa. The maximum stresses on the screws in Groups PM, PL, and PC were 166.731, 80.330, and 164.439 MPa, respectively. When the posterior tibial plateau was loaded, the displacement of the fractures in groups PM, PL, and PC was 0.410, 0.213, and 0.390 mm, respectively. The maximum stresses on the plates in groups PM, PL, and PC were 194.012 MPa, 72.806 MPa, and 185.535 MPa. The maximum stresses on the screws in Groups PM, PL, and PC were 278.265, 114.839, and 266.396 MPa, respectively. CONCLUSION: The results of this study revealed that titanium plates have good fixation effects in all groups; therefore, the use of the new plate for posterolateral tibial plateau fractures appears to be safe and valid.

A comparison between transforaminal lumbar epidural injection performed under picture archiving and communication systems-based magnetic resonance imaging planning and injection under immediate X-ray guidance.

OBJECTIVES: The study aimed to compare the treatment cost, operation time, clinical effect, and complications between punctures done under magnetic resonance imaging (MRI) planning based on picture archiving and communication systems (PACS) and punctures done under immediate X-ray fluoroscopy guidance in the treatment of lumbar disc herniation by transforaminal lumbar epidural injection. PATIENTS AND METHODS: In this prospective study conducted between October 2016 and June 2021, 128 patients were randomly divided into Groups A and B by the random number table method. In Group A (n=66; 36 males, 30 females; mean age: 64.5±2.4 years, range, 50 to 72 years), puncture was performed by planning with PACS-based MRI; in Group B (n=62; 34 males, 28 females; mean age: 65.3±2.6 years; range, 48 to 73 years), puncture was performed under immediate X-ray guidance. The cost of treatment, duration of procedure, clinical outcome, and complications were compared between the two groups. RESULTS: The difference in treatment cost in Groups A and B was statistically significant (p<0.001), with 755.67±29.45 yuan and 1.158.08±43.92 yuan, respectively. The mean treatment time was statistically significant (p<0.001) between the groups, with 21.16±1.91 min in Group A and 37.26±2 min in Group B. However, there was no significant difference between Group A and Group B in terms of improvement in pain scores and Oswestry disability index (both p>0.05). There was also no significant difference between Group A and Group B in terms of complication rates (both p>0.05). CONCLUSION: Compared to immediate X-ray guided puncture, the puncture method using PACS for MRI planning shortened the transforaminal lumbar epidural injection procedure time and reduced the treatment costs without exposing the physician or patient to additional radiation, while there was no significant difference in the short-term clinical outcome or complication rate.

Pseudotear Sign of the Anterior Horn of the Meniscus.

PURPOSE: To observe the morphology of the transverse geniculate ligament of the knee (TGL) by magnetic resonance imaging (MRI) and to analyze the cause of the pseudotear sign of the anterior horn of the meniscus caused by the TGL. METHODS: Patients who underwent MRI examination of the knee joint in the orthopaedics department of our hospital from July 2016 to August 2019 were identified. The occurrence rate, length, width, thickness, cross-sectional shape, pattern, appearance, and position relative to the anterior horn of the lateral and medial meniscus and anatomical variations were observed by multiplane and multisequence MRI. The frequency and cause of the pseudotear sign also were observed. RESULTS: The data of 101 patients were analyzed. Among them, 60 were male, and 41 were female. The average age was 42.01 (18-75) years. The occurrence rate of the TGL was 67.3% (68/101), the average length was 38.75 ± 3.56 mm, the median coronal diameter was 1.79 ± 0.60 mm, the median sagittal diameter was 1.88 ± 0.35 mm, and the cross-sectional morphology was mostly oval and round. There were 5 types of TGL connection to the anterior horn of the medial meniscus: type 1, located at the front edge; type 2, located at the upper front edge; type 3, located at the upper edge; type 4, located at the back upper edge; and type 5, was located at the back edge of the anterior horn of the medial meniscus. There was only one type of TGL insertion into the anterior horn of the lateral meniscus, located at the anterior superior edge of the anterior horn of the lateral meniscus. There were 4 cases of the pseudotear sign in the anterior horn of the meniscus, 3 in the lateral meniscus and 1 in the medial meniscus. The pseudotear sign of the anterior horn of the meniscus caused by the TGL was observed at a rate of 5.88% (4/68). CONCLUSIONS: In MRI examination of the knee, the anterior horn of the meniscus sometimes shows a pseudotear sign. According to the shape and route of the TGL on MRI and the direction and position of the pseudotear sign of the anterior horn of the meniscus, true and false tears of the anterior horn of the meniscus can be identified. LEVEL OF EVIDENCE: Level III, diagnostic study (retrospective, noncomparative, observational case series without a consistently applied reference "gold" standard).

PLA2G10 facilitates the cell-cycle progression of soft tissue leiomyosarcoma cells at least by elevating cyclin E1/CDK2 expression.

Soft tissue leiomyosarcoma (STLMS) is a major histological subtype of adult sarcoma. Although the molecular mechanisms ofLMS have been gradually revealed, no valid therapeutic targets have been identified. In this study, we performed a systematic screening to explore relapse-associated genes in STLMS, using data from The Cancer Genome Atlas-Sarcoma (TCGA-SARC). Then, we investigated the functional role of the gene with the best relapse-prediction value in STLMS by both in-vitro and in-vivo studies. Results showed that AMH and PLA2G10 were two genes with area under curve (AUC) values higher than 0.80 in ROC analysis when detecting relapse. Patients in the high AMH or PLA2G10 expression group had significantly worse relapse-free survival (RFS) compared to the respective low expression group. PLA2G10 was highly expressed in STLMS, but not in other sarcoma subtypes. PLA2G10 overexpression promoted SK-LMS-1 cell growth and G1/S transition, while PLA2G10 knockdown slowed the growth and resulted in G1 phase arrest. PLA2G10 overexpression markedly increased the expression of CDK2 and cyclin E1, but did not influence CDK4, CDK6, cyclin D1, CDK1 or cyclin A expression. PLA2G10 overexpression enhanced SK-LMS-1 cell-derived xenograft tumor growth in nude mice, while PLA2G10 inhibition slowed the growth. Mutation of two critical catalyzing amino acid residues (p.H88A and p.D89A) abrogated the capability of PLA2G10 to catalyze the production of arachidonic acid (AA), and also canceled the regulatory effects on cyclin E1 and CDK2 expression, as well as G1/S transition. In conclusion, PLA2G10 was a specific relapse-associated gene in STLMS. It facilitated the cell-cycle progression of STLMS cells at least by elevating the expression of cyclin E1 and CDK2. The hydrolytic activity was crucial for its oncogenic properties.

[Biomechanical study of nickel-titanium three-dimensional memory alloy mesh and autologous bone in treatment of canine tibial plateau collapse fracture].

Objective: To evaluate the biomechanical effect of a nickel-titanium (Ni-Ti) three-dimensional memory alloy mesh in treating a canine tibial plateau collapse fracture model and to lay a foundation for further experiments in vivo. Methods: Sixteen tibial plateau specimens of 8 adult Beagle dogs were harvested. Twelve specimens were taken to prepare canine tibial plateau collapse fracture models (Schatzker type Ⅲ) and randomly divided into groups A, B, and C, with 4 specimens in each group. Four normal tibia specimens were used as blank control group (group D). In groups A and B, the bone defects were repaired with Ni-Ti three-dimensional shape memory alloy mesh combined with autologous bone and simple autologous bone respectively, and fixed with the lateral plate and screw. In group C, the bone defect was directly fixed with the lateral plate and screw. By using a biomechanical tester, a progressive load (0-1 700 N) was loaded vertically above the femoral condyle. The maximum failure load was recorded and the stiffness was calculated according to the load-displacement curve. Results: The maximum failure loads in groups A, B, C, and D were (1 624.72±7.02), (1 506.57±3.37), (1 102.00±1.83), and (1 767.64±24.56) N, respectively; and the stiffnesses were (129.72±20.83), (96.54±27.05), (74.96±17.70), and (169.01±35.62) N/mm, respectively. The maximum failure load and stiffness in group A were significantly higher than those in groups B and C, but which were significantly lower than those in group D ( P<0.05). Conclusion: Ni-Ti three-dimensional memory alloy mesh combined with autologous bone can repair the Schatzker type Ⅲ tibial plateau collapse fracture, which has better biomechanical properties than simple autologous bone grafting.

[Application of skin stretcher for repair of postoperative skin and soft tissue defects in tibial fractures].

Objective: To discuss the efficacy of skin stretcher applied for repair of postoperative skin and soft tissue defects in tibial fractures. Methods: Between April 2016 and March 2017, 15 cases with skin and soft tissue defects after tibial fractures fixation were treated with the skin stretcher. There were 11 males and 4 females with an age of 24-59 years (mean, 37.5 years). The causes of injury included traffic accident in 7 cases, bruise in 3 cases, falling from height in 3 cases, and falling in 2 cases; without nerve and vascular injury in all patients. These cases were followed up 1-3 months after their first surgery, consisting of 3 closed fractures treated with open reduction and plate and screw fixation, 12 open fractures treated with external fixation after debridement. The area of skin defects ranged from 14 cm×5 cm to 20 cm×7 cm, all of which were stripped or spindle shaped skin defects. First, the skin was penetrated by two Kirschner wires which were locked by skin stretchers on both sides of the skin defect longitudinally. Then, the tension of skin stretchers was timely adjusted according to the skin flap blood supply and muscle compression. Finally, Kirschner wires and skin stretchers were removed when the edge of skin contacted and been sutured. Results: All skin and soft tissue defects were covered after stretching for 6-13 days. The interrupted sutured wounds healed at 12 days. Clinical scores of wound healing decreased from 3.40±0.51 at immediate postoperatively to 1.27±0.46 at 12 days postoperatively, showing significant difference ( t=12.911, P=0.000). All the patients were followed up 4-12 months (mean, 6.5 months). After stretching, the skin color, elasticity, and pain and touch feeling were similar with the normal skin, and the hair growth was normal. After operation, 1 case of nail tract infection and 2 cases of calf discomfort occurred, and all were relieved after treatment. Conclusion: It is an effective method for repairing postoperative skin and soft tissue defects in tibial fractures with the application of skin stretchers.