It was a retrospective case–control study. The aim of this study was to explore the clinical efficacy and complication of treatment using a modified Kirschner wire tension band (MKTB) or a cannulated screw tension band (CSTB) in transverse patellar fractures.In total, 55 patients with transverse patellar fractures were retrospectively reviewed and divided into 2 groups according to the surgical technique: 29 patients were in the MKTB group and 26 patients in the CSTB group. Bǒstman's clinical grading scale, including range of movement (ROM), pain, ability to work, atrophy of quadriceps femoris, assistance in walking, effusion, giving way, and stair-climbing, was used to evaluate the clinical results. Complications including painful hardware, implant loosening or breakage, and bone nonunion were also assessed.Both groups were evaluated at the final follow-up before removing implant in the MKTB group. The Bǒstman's score of ROM, pain, atrophy of quadriceps femoris, and effusion were all higher in the CSTB group than in the MKTB group (P < 0.05). Twelve patients in the MKTB group underwent implant removal, and the score of ROM, pain, and effusion were higher than before removing implant (P < 0.05), but there was no difference compared to the CSTB group (P > 0.05). Seventeen patients achieved excellent results, 9 had good results, and 3 reported fair results in the MKTB group; the CSTB group had excellent results in 22 patients and good results in 4 patients, showing a significant difference in the excellent rate between the 2 groups (P = 0.021). Total Bǒstman scores in the MKTB and CSTB groups (26.96 ± 4.47 and 29.42 ± 1.47, respectively) were significantly different (P = 0.01). Total scores in the MKTB group after removing implant were higher than those before removing implant (P = 0.001), and similar to those in the CSTB group (P = 0.224). Eleven patients in the MKTB group reported painful hardware, including 4 cases of implant loosening.CSTB achieves better clinical results than MKTB, meanwhile avoiding the problems of painful hardware and implant loosening. Functional limitation caused by hardware pain was commonly seen in the MKTB group, and removing implant after fracture healing improved knee function.

Background/Aims: Krüppel-like factor 2 (KLF2) plays an essential role in the inhibition of endothelial cell and macrophage activation during the inflammatory process. However, the roles of KLF2 in chondrocytes and the pathological progression of osteoarthritis (OA) remain unknown. The aim of this study was to investigate the function of KLF2 in the inhibition of cartilage matrix destruction in chondrocytes. Methods: RT-PCR and western blot analysis was used to determine the expression of KLF2 in human chondrocytes. Luciferase assay, ELISA assay and MMP-13 enzymatic activity assays were used to investigate the effects of KLF2 in regulating MMP-13 expression. Western blot analysis was used to examine the effects of KLF2 in suppressing degradation of type Ⅱ collagen. Results: KLF2 is expressed in primary chondrocytes and is downregulated in OA chondrocytes. Expression of KLF2 in primary chondrocytes was reduced in response to IL-1β. Overexpression of KLF2 robustly inhibited IL-1β-induced MMP-13 expression. Conversely, knockdown of KLF2 markedly exacerbated MMP-13 expression. Mechanistically, KLF2 could suppress the activation of MMP-13 promoter. However, knockdown of KLF2 could promote the activation of MMP-13 promoter. Importantly, overexpression of KLF2 ameliorated the degradation of type Ⅱ collagen while silencing of KLF2 exacerbated the degradation of type Ⅱ collagen induced by IL-1β. Conclusions: KLF2 may be a potential therapeutic target for OA treatment.

As a commonly used implant material, calcium sulfate cement (CSC), has some shortcomings, including low compressive strength, weak osteoinduction capability, and rapid degradation. In this study, silica-based mesoporous materials such as SBA-15 were synthesized and combined with CSC to prepare CSC/SBA-15 composites. The properties of SBA-15 were characterized by X-ray diffraction, transmission electron microscopy, and nitrogen adsorption–desorption isotherms. SBA-15 was blended into CSC at 0, 5, 10, and 20 wt%, referred to as CSC, CSC-5S (5% mass ratio), CSC-10S (10% mass ratio), and CSC-20S (20% mass ratio), respectively. Fourier-transform infrared spectroscopy and compression tests were used to determine the structure and mechanical properties of the composites, respectively. The formation of hydroxyapatite on composite surfaces was analyzed using scanning electron microscopy and X-ray diffraction after soaking in simulated body fluid. BMP-2 was loaded into the composites by vacuum freeze-drying, and its release characteristics were detected by Bradford protein assay. The in vitro degradation of the CSC/SBA-15 composite was investigated by measuring weight loss. The results showed that the orderly, nanostructured, mesoporous SBA-15 possessed regular pore size and structure. The compressive strength of CSC/SBA-15 increased with the increase in SBA-15 mass ratio, and CSC-20S demonstrated the maximum strength. Compared to CSC, hydroxyapatite that formed on the surfaces of CSC/SBA-15 was uniform and compact. The degradation rate of CSC/SBA-15 decreased with increasing mass ratio of SBA-15. The adsorption of BMP-2 increased and released at a relatively slow rate; the release rate of BMP-2 in CSC-20S was the slowest, and presented characteristics of low doses of release. In vitro experiments demonstrated that the physical properties of pure CSC incorporated with SBA-15 could be improved significantly, which made the CSC/SBA-15 composite more suitable for bone repair and bone-tissue engineering.

Vibration is everywhere in of our daily life. This paper studies the effect of rectangular pulse and free vibration on multi-degree of freedom systems. An undamped three-floor shear frame structure subjected to rectangular pulse and a damping three-floor shear building considered free vibration is investigated with respect to natural frequencies, mode shapes, and displacements of each floor level. This paper assumes the three-story shear building structure discussed has orthogonal damping, and the fundamental frequency will not change over time, which means that the mode shape of the system does also not change with time. In addition, the modal superposition method and Duhamel integrals are useful to study the response of the various vibration systems. In this work, it can be concluded that the main response is due to the vibrations’ first mode, even though all its mode shapes can lead to free vibration response. For amplitude of the motion, it will change with the frequency of excitation. When the non-periodic impulse is applied, the forced vibration will be different in the short duration of the impulse with the free vibration phase.