Choose the appropriate implantation position of the Femoral Neck System in the femoral neck: a finite-element analysis.

PURPOSE: There is no specific literature on the best implantation position of the Femoral Neck System (FNS) for treating Pauwels type III femoral neck fracture in young adults. METHODS: Use finite-element analysis to compare the mechanical properties of implantation positions: FNS in the central position, FNS in the low position, and FNS in the low position combined with cannulated screw (CS). The CT data of the femur were imported into the mimics20.0 to obtain the three-dimensional model of the femur; imported into geomagic2017 and SolidWorks 2017 for optimizations; models of FNS and CS are built on the basis of the device manuals. Grouping is as follows: FNS group, FNS-LOW group, and FNS-CS group. Assemble and import them into abaques6.14 for load application. The displacement distribution and von Mises Stress value of them were compared. RESULTS: On femoral stability and stress distribution, the FNS-CS group performs best, followed by the FNS-LOW group, and finally FNS group. The FNS-LOW group has an improvement over the FNS group but not by much. CONCLUSION: In operations, when the implantation position of the central guide wire is not at the center of the femoral neck but slightly lower, it is recommended not to adjust the wire repeatedly in pursuit of the center position; for femoral neck fractures that are extremely unstable at the fracture end or require revision, the insertion strategy of FNS in the low position combined with CS can be adopted to obtain better fixation effects.

Circulating microRNAs, miR-10b-5p, miR-328-3p, miR-100 and let-7, are associated with osteoblast differentiation in osteoporosis.

Osteoporosis has become a major disease that threatened post-menopausal women and elder people. Circulating micorRNAs (miRNA) could provide useful information for diagnosis and therapeutics. The study employed RT-real time PCR to detect the circulating miRNAs between osteoporotic patients and healthy controls. Human and mouse osteoblast cell lines were used to test the differential induction effects by miRNAs. Alkaline phosphatase activity and Alizarin red staining were examined after miRNA mimics stimulation. The authors found 14 of 150 tested miRNAs were significantly aberrant expressed between patients and healthy controls. Results showed miR-328-3p, let-7g-5p, miR-133b, miR-22-3p, miR-2861, miR-518 miR-100 were down-regulated osteoporotic patient, while miR-10b-5p, miR-21, miR-125b and miR-127 were up-regulated. MiR-10b-3p, miR-328-3p, miR-100 and let-7 showed tight association with Wnt pathway. MiR-10b-5p increased ALP activity and mineral deposition in human and mouse osteoblast cells, indicating miR-10b-3p promoted osteoblast cell differentiation. MiR-328-3p and let-7g-5p decreased ALP activity and suppressed mineral deposition in both cell lines. Conclusively, miR-10b-5p promoted osteoblast cells differentiation; miR-328-3p, miR-100 and let-7 inhibited osteoblast cells differentiation.

BMP-7 ameliorates cobalt alloy particle-induced inflammation by suppressing Th17 responses.

Metal wear debris has been shown to activate an aseptic osteolytic process that causes failure in total joint arthroplasty (TJA). This osteolysis is characterized by a proinflammatory, self-propagating immune response involving primarily macrophages, dendritic cells, and activated osteoclasts, as well as T cells and B cells. The human bone morphogenic protein (BMP)-7, on the other hand, was shown to promote osteoblast survival, and reversed the downregulation of anabolic Smad proteins and Runx2 following cobalt injury. Therefore, we investigated the effect and mechanism of BMP-7 on the proinflammatory immune responses in osteoarthritis patients with previous TJA. Cobalt-treated monocytes/macrophages presented significantly elevated levels of interleukin 6 (IL-6) and tumor necrosis factor (TNF), both of which were suppressed by the addition of exogenous BMP-7. In patients with TJA, the serum BMP-7 level was inversely associated with the level of IL-6 and TNF secreted by monocytes/macrophages. Cobalt-treated monocytes/macrophages effectively supported Th17 inflammation, by an IL-6-dependent but not TNF-dependent mechanism. BMP-7, however, significantly suppressed cobalt-induced Th17 inflammation. In patients with TJA, the risk of osteolysis development was positively associated with the frequency of Th17 cells and negatively associated with the level of BMP-7. Together, these results demonstrated that BMP-7 could serve as a therapeutic agent in treating patients with metal wear debris-induced inflammation.

Treatment of middle-super thoracic fractures associated with the sternum fracture.

To analyze the characteristics and treatment of middle-super thoracic fractures associated with the sternum fracture, twenty six patients with middle-super thoracic fractures associated with the sternum fracture were retrospectively reviewed. The intimate information of patients including age, gender, cause of injury, site of the sternal fracture, level and type of thoracic vertebral fracture, spinal cord injury and associated injuries were included in the analysis. There were 12 compressed fractures, 11 fracture-dislocations, two burst fracture and one burst-dislocation in this study. Six patients had a complete lesion of the spinal cord, nine sustained a neurologically incomplete injury and 11 were neurologically intact. Nine patients were treated non-operatively and 17 were underwent surgery. All patients were followed up for 8~99 months. Our results showed that road traffic accidents (RTA) and fall were the dominated in the causes. All six patients with a complete paralytic lesion were not recovered with any significant function. Four out of eleven neurologically intact patients had local pain although ten of them remained normal function and one patient turn up tardive paralysis. One of nine patients with incomplete paraplegia returned to normal and four recovered with some function. These study suggested that the sternum is one of the important parts in constructing thoracic cage and plays an important role in maintain the stabilization of the thoracic vertebra. Because of the unique anatomy and biomechanics of the thoracic cage, the classification commonly applied to thoracic vertebra fractures is not suitable for middle-super thoracic fractures associated with the sternum fracture. Middle-super thoracic fractures associated with the sternum fracture was marked by violent force, severe fractures of spine, severe injuries of spinal cord and high incidence of associated injuries. These cases confirm the existence and clinical relevance of the fourth column of the thoracic spine and its role for spinal stability in the patient with middle-super thoracic fracture.

Effect of culture complex of BMSCs and sodium hydroxide- and GRGDSPC-treated PET on the reconstruction of injured anterior cruciate ligament in a rabbit model.

Ligament reconstruction is an effective therapy for anterior cruciate ligament (ACL) rupture. Polyethylene terephthalate (PET) artificial ligaments have recently gained popularity in clinical ACL reconstruction for its advantage in the improvement of keen function. However, the application of PET in clinical treatment is limited by its poor bioactivity and biocompatibility. Recently, bone marrow-derived mesenchymal stem cells (BMSCs) have been widely studied in regenerative medical therapy due to their multi-lineage differentiation. Previous study also indicated that BMSCs may promote the healing of tendon-bone interface of injured ligament. We speculate that BMSCs may enhance the curative effect of PET artificial ligament on the tendon-bone-healing in ligament reconstruction. In this study, the PET materials were first modified with sodium hydroxide hydrolysis and GRGDSPC peptide which was able to improve its bioactivity and biocompatibility. Then, the effects of modified PET materials on the adhesion, proliferation and differentiation of BMSCs were examined. The in vitro co-culture of BMSCs and modified PET showed the modified PET promoted the adhesion, proliferation and differentiation of BMSCs. Further, the effect of culture complex of BMSCs and modified PET artificial ligament co-culture system on the injured ligament reconstruction was investigated in vivo. Results showed not only better growth and differentiation of BMSCs but also satisfactory healing of the injured ligament was observed after implantation of this culture complex into the injured ligament of rabbits. Our study provides a brand-new solution for ACL reconstruction.

Fast pinless external fixation for open tibial fractures: preliminary report of a prospective study.

A major drawback of conventional fixator system is the penetration of fixator pins into the medullary canal. The pins create a direct link between the medullary cavity and outer environment, leading to higher infection rates on conversion to intramedullary nailing. This study was designed to prospectively evaluate the role of new rapid pinless external fixators in primary stabilization of open tibial shaft fractures. In our study, a prospective study of 96 consecutive patients of open tibial shaft fractures treated with new rapid pinless external fixator and reamed intramedullary nail was carried out. The bone healing status, ability to maintain alignment were examined for radiologic outcome, whereas initial management, length of hospital stay, associated morbidity, range of knee and ankle motion, time to partial and full weight-bearing, employment status and perioperative and postoperative complications were used for clinical evaluation. We followed up for over two years for the patients underwent clinical and radiologic after the surgery. The mean hospital stay was 15 days (ranges, 8-68). Bone healing was achieved for all cases except 3 patients who were lost to follow-up study. No patient suffered compartment syndromes. There was no statistically significance in range of motion among the knees of injury and uninjured limbs at final follow-up (P > 0.05). To the last follow-up, there were no cases of deep infection or implant-related fractures. Seventy-one patients who were employed before the injury returned to work after the operation, 16 had changed to less strenuous work. We concluded that better results can be achieved on clinical and radiologic evaluation of primary stabilization with rapid pinless external fixator and early exchange reamed intramedullary nail for suitable patients with open tibial shaft fractures. The incident rate of relative complications is low. The rapid pinless external fixator can be combined favorably with the reamed intramedullary nail and is a valuable addition to the conventional external fixator systems.

Characteristics of bone tunnel changes after anterior cruciate ligament reconstruction using Ligament Advanced Reinforcement System artificial ligament.

BACKGROUND: There are different materials used for anterior cruciate ligament (ACL) reconstruction. It has been reported that both autologous grafts and allografts used in ACL reconstruction can cause bone tunnel enlargement. This study aimed to observe the characteristics of bone tunnel changes and possible causative factors following ACL reconstruction using Ligament Advanced Reinforcement System (LARS) artificial ligament. METHODS: Forty-three patients underwent ACL reconstruction using LARS artificial ligament and were followed up for 3 years. X-ray and CT examinations were performed at 1, 3, 6, 12, 24, and 36 months after surgery, to measure the width of tibial and femoral tunnels. Knee function was evaluated according to the Lysholm scoring system. The anterior and posterior stability of the knee was measured using the KT-1000 arthrometer. RESULTS: According to the Peyrache grading method, grade 1 femoral bone tunnel enlargement was observed in three cases six months after surgery. No grade 2 or grade 3 bone tunnel enlargement was found. The bone tunnel enlargement in the three cases was close to the articular surface with an average tunnel enlargement of (2.5 ± 0.3) mm. Forty cases were evaluated as grade 0. The average tibial and femoral tunnel enlargements at the last follow-up were (0.8 ± 0.3) and (1.1 ± 0.3) mm, respectively. There was no statistically significant difference in bone tunnel width changes at different time points (P > 0.05). X-ray and CT measurements were consistent. CONCLUSIONS: There was no marked bone tunnel enlargement immediately following ACL reconstruction using LARS artificial ligament. Such enlargement may, however, result from varying grafting factors involving the LARS artificial ligament or from different fixation methods.

[Treatment and classification of thoracic fracture accompanied with sternum fracture].

OBJECTIVE: To determine the characteristics, classification, and treatment of thoracic fracture accompanied with sternum fracture. METHODS: Data of 32 patients with thoracic fractures accompanied with sternum fracture were reviewed. Patients information such as age, gender, cause of injury, site of sternum fracture, level and type of thoracic vertebral fracture, spinal cord injury and associated injuries was included in the analysis. Of the 32 patients, 13 had compressed fractures, 13 had fracture-dislocations, 5 had burst fracture and 1 had burst-dislocation. Six patients had a complete lesion of the spinal cord, 13 sustained a neurologically incomplete injury, and the other 13 were neurologically intact. Ten patients were treated nonoperatively and the other 22 surgically. RESULTS: All patients were followed up for 10-103 months. Road traffic accidents and falling dominated among the causes. All patients were accompanied with other injuries. None of the 6 patients with a complete paralitic lesion regained any significant function. Of the 13 neurologically intact patients, 5 had local pain although 12 of them remained normal function. One patient showed tardive paralysis. Three of the 13 patients with incomplete paraplegia returned to normal, 5 regained some function and 5 did not recover. CONCLUSION: Thoracic fractures accompanied with sternum fracture are marked by violent force, severe fracture of the spine, severe injuries of the spinal cord, and high incidence of other injuries. The new classification method is more suitable to thoracic fractures accompanied with sternum fracture,and confirms the existence and clinical relevance of the 4th column of the thoracic spine and its role in providing spinal stability in patients with thoracic fracture.