The effects of SDF-1 combined application with VEGF on femoral distraction osteogenesis in rats.

Bone regeneration and mineralization can be achieved by means of distraction osteogenesis (DO). In the present study, we investigated the effect of stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) on the new bone formation during DO in rats. Forty-eight Sprague-Dawley rats were randomized into four groups of 12 rats each. We established the left femoral DO model in rats and performed a mid-femoral osteotomy, which was fixed with an external fixator. DO was performed at 0.25 mm/12 h after an incubation period of 5 days. Distraction was continued for 10 days, resulting in a total of 5 mm of lengthening. After distraction, the solution was locally injected into the osteotomy site, once a day 1 ml for 1 week. One group received the solvent alone and served as the control, and the other three groups were treated with SDF-1, VEGF, and SDF-1with VEGF in an aqueous. Sequential X-ray radiographs were taken two weekly. The regeneration was monitored with the use of micro-CT analysis, mechanical testing, and histology. Radiographs showed accelerated regenerate ossification in the SDF-1, VEGF, and SDF-1 with the VEGF group, with a larger amount of new bone compared with the control group, especially SDF-1 with the VEGF group. Micro-CT analysis and biomechanical tests showed Continuous injection of the SDF-1, VEGF, and SDF-1 with VEGF during the consolidation period significantly increased bone mineral density bone volume, mechanical maximum loading, and bone mineralization of the regenerate. Similarly, the expression of osteogenic-specific genes, as determined by real-time polymerase chain reaction , was significantly higher in SDF-1 with the VEGF group than in the other groups. Histological examination revealed more new trabeculae in the distraction gap and more mature bone tissue for the SDF-1 with the VEGF group. SDF-1 and VEGF promote bone regeneration and mineralization during DO, and there is a synergistic effect between the SDF-1 and VEGF. It is possible to provide a new and feasible method to shorten the period of treatment of DO.

[Comparison of effectiveness of lower extremity axial distractor and traction table assisted closed reduction and intramedullary nail fixation in femoral subtrochanteric fracture].

Objective: To compare the effectiveness of lower extremity axial distractor (LEAD) and traction table assisted closed reduction and intramedullary nail fixation in treatment of femoral subtrochanteric fracture. Methods: The clinical data of 117 patients with subtrochanteric fracture of femur treated by closed reduction and intramedullary nail fixation between May 2012 and May 2022 who met the selection criteria were retrospectively analyzed. According to the auxiliary reduction tools used during operation, the patients were divided into LEAD group (62 cases with LEAD reduction) and traction table group (55 cases with traction table reduction). There was no significant difference in baseline data, such as gender, age, injured side, cause of injury, fracture Seinsheimer classification, time from injury to operation, and preoperative visual analogue scale (VAS) score, between the two groups ( P>0.05). Total incision length, operation time, intraoperative blood loss, fluoroscopy frequency, closed reduction rate, fracture reduction quality, fracture healing time, weight-bearing activity time, and incidence of complications, as well as hip flexion and extension range of motion (ROM), Harris score, and VAS score at 1 month and 6 months after operation and last follow-up were recorded and compared between the two groups. Results: There were 14 cases in the LEAD group from closed reduction to limited open reduction, and 43 cases in the traction table group. The incisions in the LEAD group healed by first intention, and no complication such as nerve and vascular injury occurred during operation. In the traction table group, 3 cases had perineal crush injury, which recovered spontaneously in 1 week. The total incision length, operation time, intraoperative blood loss, fluoroscopy frequency, and closed reduction rate in the LEAD group were significantly better than those in the traction table group ( P<0.05). There was no significant difference in the quality of fracture reduction between the two groups ( P>0.05). Patients in both groups were followed up 12-44 months, with an average of 15.8 months. In the LEAD group, 1 patient had delayed fracture union at 6 months after operation, 1 patient had nonunion at 3 years after operation, and 1 patient had incision sinus pus flow at 10 months after operation. In the traction table group, there was 1 patient with fracture nonunion at 15 months after operation. X-ray films of the other patients in the two groups showed that the internal fixator was fixed firmly without loosening and the fractures healed. There was no significant difference in fracture healing time, weight bearing activity time, incidence of complications, and postoperative hip flexion and extension ROM, Harris score, and VAS score at different time points between the two groups ( P>0.05). Conclusion: For femoral subtrochanteric fracture treated by close reduction and intramedullary nail fixation, compared with traction table, LEAD assisted fracture reduction can significantly shorten the operation time, reduce intraoperative blood loss and fluoroscopy frequency, reduce incision length, effectively improve the success rate of closed reduction, and avoid complications related to traction table reduction. It provides a new method for good reduction of femoral subtrochanteric fracture.

Application of PVC pipes as an adjustable bilateral traction device in lower limb fractures.

OBJECTIVE: To introduce a new type of simple adjustable bilateral bidirectional polyvinyl chloride (PVC) tube traction device and discuss the value of using this device before surgery in patients with lower limb fractures. METHODS: To introduce the manufacturing process of an adjustable bilateral traction device made of PVC pipes. From August 2018 to November 2019, the data of 36 patients with lower limb fractures who were treated with this traction device were retrospectively analysed. The treatment outcomes were analysed, including length of both lower limbs, fracture reduction, lower limb mobility, visual analogue scale (VAS) score, incidence of complications, and patient satisfaction. RESULTS: All patients were able to move the affected limb immediately after using the device. The patient's pain was significantly reduced, they were able to turn over freely during bed rest, and the length of the affected limb was restored to that of the healthy limb. Thirty-four (94.5%) patients were satisfied with the reduction of the fracture end, 2 (5.5%) patients with tibiofibular fractures showed angular displacement of the fractured end and satisfactory reduction after the position of the bone traction needle was adjusted; 7 (19.5%) patients developed deep vein thrombosis of the affected lower limb during traction; there was no decubitus or vascular nerve injury, and the overall complication rate was 25% (9/36). All the patients and their families were satisfied with the results of this treatment. CONCLUSION: The aim of this study is to introduce a new type of traction device. It is advantageous in that it is light weight, low cost, easy to assemble, promotes immediate movement of the affected limb after assembly, improves patient comfort and can be used with a titanium steel needle for MRI examination under traction. In the clinical setting, it has been shown to be suitable for the temporary treatment of patients with lower leg fractures prior to surgery, particularly patients who, for various reasons, require nonsurgical treatment in the short term.

CD73 inhibits titanium particle-associated aseptic loosening by alternating activation of macrophages.

Aseptic inflammation is a major cause of late failure in total joint arthroplasty, and the primary factor contributing to the development and perpetuation of aseptic inflammation is classical macrophage activation (M1 phenotype polarization) induced by wear particles. CD73 (ecto-5'-nucleotidase) is an immunosuppressive factor that establishes an adenosine-induced anti-inflammatory environment. Although CD73 has been shown to suppress inflammation by promoting alternate macrophage activation (M2 phenotype polarization), its role in wear particle-induced aseptic inflammation is currently unknown. Our experiments were based on metabolomic assay results in a mouse model of aseptic loosening, and studied the function of CD73 in vivo and in vitro using a mouse aseptic loosening model and a mouse bone marrow derived macrophage (BMDM) inflammation model. Results show that aseptic loosening (AL) reduces the purine metabolic pathway and decreases the native expression of the metabolite adenosine. In vivo, CD73 expression was low in the bone tissue surrounding the titanium nail and synovial-like interface tissue, while in vitro experiments demonstrated that CD73 knockdown promoted titanium particles-induced aseptic inflammation. CD73 overexpression mitigated the titanium particle-mediated enhancement of LPS-induced M1 polarization while promoting the titanium particle-mediated attenuation of IL-4-induced M2 polarization. In BMDM exposed to titanium particles, CD73 promotes M2 polarization via the p38 pathway. Meanwhile, local injection of recombinant mouse CD73 protein slightly alleviated the progression of AL. Collectively, our data suggest that CD73 alleviates the process of AL, and this function is achieved by promoting alternate activation of macrophages.

Concentration Changes of Peripheral Blood Mesenchymal Stem Cells of Sprague Dawley Rats during Distraction Osteogenesis.

OBJECTIVES: To observe the changes in the concentrations of circulating peripheral blood mesenchymal stem cells (PBMSCs) in Sprague Dawley (SD) rats and explore the pattern of changes in PBMSCs during the process of distraction osteogenesis. METHODS: SD rats were randomly divided into the osteotomy with lengthening group (lengthening group), the osteotomy without lengthening group (osteotomy group), and the blank control group (control group). Each group included 24 rats. Percutaneous pinning with external fixation of the left femur was carried out in lengthening group and osteotomy group, but control group received no surgical treatment. On day 5 after operation, continuous traction was carried out at a rate of 0.25 mm/d in lengthening group, while no traction was carried out in osteotomy group. Peripheral blood was collected from all rats on days 1, 3, 7, and 16 after the start of traction. PBMSCs were isolated by density gradient centrifugation. CD105, CD34, and CD45 were selected as cell surface markers. The concentration of PBMSCs was detected by flow cytometry and compared between groups at different time points. X-ray films were taken during and after the operation to observe whether the osteotomy end was pulled and the growth and mineralization of the new bone in the osteogenic area of the femur. Color ultrasound was used to monitor the width of the distraction space, the formation of new bone, and the blood supply of soft tissue around the distraction. RESULTS: All rats were able to tolerate the operation well, and the external fixation was firm and reliable. X-ray showed that, in lengthening group, the distraction space of femur gradually widened and new bone gradually formed in the distraction space; after 8 weeks, the samples were taken out, which showed that the new bone tissue in the lengthened area healed well. In osteotomy group, the average healing time of osteotomy was (7.12 ± 0.78) weeks. Ultrasonic examination showed that after the end of traction, the high echo callus shadow was seen in the traction space, and the blood flow signal was obviously rich at an earlier stage. In lengthening group and osteotomy group, the average concentrations of PBMSCs (3.02% ± 0.87% vs 2.95% ± 0.74%, respectively) were significantly increased in the early stage after osteotomy, and the average concentrations of PBMSCs on days 3, 7, and 16 after the start of traction were 5.34% ± 1.13% vs 3.28% ± 1.22%; 6.41% ± 1.05% vs 3.16% ± 0.92%; and 5.94% ± 1.23% vs 1.48% ± 0.52%, respectively. The concentration of PBMSCs in peripheral blood of lengthening group and osteotomy group was the same at osteotomy stage, and the difference between the two groups was not statistically significant (P > 0.05). After that, compared with lengthening group, the concentration of PBMSCs in osteotomy group gradually decreased and maintained at a certain level; the difference between the two groups was statistically significant (P < 0.05). CONCLUSIONS: Distraction osteogenesis of femur can significantly increase PBMSCs in SD rats and participate in the process of bone formation.

[A comparative study on effectiveness of closed reduction and internal fixation of intertrochanteric fracture assisted with skeletal tractor and traction table].

OBJECTIVE: To investigate the effectiveness and advantages of skeletal tractor in closed reduction and proximal femoral nail antirotation (PFNA) internal fixation of intertrochanteric fracture compared with traction table. METHODS: The clinical data of 86 patients with intertrochanteric fractures, who were treated with closed reduction and PFNA internal fixation between October 2016 and March 2018 and met the selection criteria, was retrospectively analysed. Among them, 44 cases were treated with skeletal tractor (trial group) and 42 cases were treated with traction table (control group). There was no significant difference between the two groups in gender, age, cause of injury, fracture side, AO classification, and degree of osteoporosis ( P>0.05). The preoperative position time, operation time, intraoperative fluoroscopy times, intraoperative blood loss, fracture healing time, intraoperative and postoperative complications, and postoperative Harris score were compared between the two groups. RESULTS: The operation was successfully completed in both groups. Compared with the control group, the patients in the trial group had shorter preoperative position time and operation time, fewer intraoperative fluoroscopy times, and less intraoperative blood loss ( P<0.05). The patients were followed up 12-21 months in trial group (mean, 14.2 months) and 12-22 months in control group (mean, 14.3 months). Venous thrombosis of lower extremity occurred in 8 patients (3 cases of trial group and 5 cases of control group) after operation. Internal fixation failure occurred in 5 patients (2 cases of trial group and 3 cases of control group) during 1 year after operation. All fractures healed except for those with internal fixation failure, the fracture healing time was (11.6±2.9) weeks in trial group and (12.4±3.6) weeks in control group; and there was no significant difference between the two groups ( t=1.250, P=0.214). At 1 year after operation, Harris score of the trial group was 86.2±5.9 and that of the control group was 84.1±6.1. There was no significant difference between the two groups ( t=1.768, P=0.080). CONCLUSION: Compared with traction table, skeletal tractor in closed reduction and PFNA internal fixation of intertrochanteric fracture can significantly shorten the preoperative position time and operation time, reduce the intraoperative fluoroscopy times, improve the operation efficiency, and have similar effectiveness.

A minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions: Nose ring drainage technique.

Morel-Lavallée lesions (MLLs) are shearing injuries resulting in separation of the skin and subcutaneous tissue from the underlying fascia. They are closed internal degloving injuries. Classical sites of the lesions are around the greater trochanter, pelvis, thigh, knee joint, and on the head, in decreasing order of frequency. This injury is often delayed or misdiagnosed when patients present with soft tissue injury alone or when more obvious injuries distract from its presence in polytrauma patients. There is currently no universally accepted treatment for these lesions. Conservative management often fails and requires surgical intervention. The purpose of this manuscript is to show that nose ring drainage, a minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions, is effective and economical.