Effects of Moisture Content and Loading Profile on Changing Properties of Bone Micro-Biomechanical Characteristics.

BACKGROUND Our study explored the influences of hydration conditions and loading methods on the mechanical properties of cortical bones and cancellous bones. MATERIAL AND METHODS Elastic modulus and hardness of human cortical bones and cancellous bones that contained different moisture levels (20%, 30%, 40%, 50%, and 60%) were measured with nanoindentation with different peak loads and loading rates. Cortical bones with 20% and 60% moisture were tested with 30 nm, 40 nm, and 50 nm peak loads at 6 nm/s, 8 nm/s, and 10 nm/s loading rates, respectively. Cancellous bones with 5% or 40% moisture percentages were tested with 600 µN, 750 µN, and 1000 µN peak loads at 200 µN/s, 250 µN/s, and 333 µN/s loading rates, respectively. RESULTS Under the same loading condition, specimens with higher moisture contents showed decreased elastic modulus and hardness. Under different loading conditions, the loading modes had little influence on elastic modulus and hardness of cortical bone and cancellous bone with low moisture, but had significant influence on specimens with higher moistures. CONCLUSIONS The elastic modulus and bone hardness were affected by the moisture content and the loading conditions in cortical and cancellous bones with high hydration condition but not in those with low hydration condition.

[Preliminary study for classification of spino-pelvic sagittal alignment in adult volunteers].

OBJECTIVE: To investigate the feasibility of the classification of the spino-pelvic sagittal alignment in adluts according to lumbar lordosis (LL) and inflection point (IP). METHODS: Whole spine, standing radiographs of 223 adult volunteers were taken from July to August in 2011 .There were 111 cases(56 female and 55 male) enrolled in the study based on the inclusion criteria. The pelvic and spinal parameters, including thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), LL, sacral slope(SS), pelvic tilt(PT), pelvic incidence(PI), intervertebral endplate angle, sagittal vertical axis (SVA), spino-sacral angle (SSA) and IP were measured. The spino-pelvic sagittal alignment were classified in to 3 types according to LL and IP. Type I: LL > -40°, IP located below L2 ∼ 3; Type II: -60° ≤ LL ≤ -40°, IP located in L1 ∼ 2 or T12 ∼ L1; Type III: LL < -60°, P located above T11 ∼ 12. Pearson correlation analysis was used to test the correlation between the variables. The parameters in each type were compared by oneway-ANOVA respectively,then additional multiple comparisons were performed. RESULTS: The mean value of LL was -49° ± 10°, TK was 36° ± 7°, TLK was 6° ± 7°, PT was 11° ± 7°, SS was 34° ± 8°, PI was 45° ± 9°, SSA was 127° ± 9° and SVA was (-2.7 ± 22.8)mm, respectively. Only LL had significant statistical correlation with all the other parameters. Negative correlation presented between LL and TK, PI, SS, SSA (r = -0.387, -0.536, -0.858, -0.801,P < 0.05). Positive correlation presented between LL and TLK, SVA, PT (r = 0.319, 0.296, 0.262, P < 0.05). All the volunteers were classified into the 3 types: Type I1 9 cases, Type II 75 cases,Type III 17 cases. Oneway-ANOVA results showed statistical difference in LL, TK, TLK, PT, SS, PI, SSA, SVA among the 3 types, (F = 164.559, 7.431, 14.099, 4.217, 53.856, 6.252, 35.995, 8.626, P < 0.05 ). Multiple comparisons showed that LL, SS, SSA, PI had statistical difference between each two types comparison (P < 0.05). CONCLUSIONS: LL is the central parameter of the spino-pelvic sagittal balance. The patterns of the spino-pelvic sagittal alignment in adults could be classified into three types, according to LL and IP. The classification could describe the morphological differences and balance of the spino-pelvic sagittal alignment.

[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.

[Treatment of unstable femoral neck fracture with posteromedial comminutations by cannulated screws and medial bracing plate combined with bone allograft].

OBJECTIVE: To evaluate the effectiveness of unstable femoral neck fracture with posteromedial comminutations treated by cannulated screws and medial bracing plate combined with bone allograft. METHODS: The clinical data of 18 patients with unstable femoral neck fracture with posteromedial comminutations treated by cannulated screws and medial bracing plate combined with bone allograft between July 2016 and March 2020 were retrospectively analyzed. The age ranged from 22 to 64 years, with a median age of 43 years. The causes of injury included 11 cases of falling injury, 3 cases of traffic accident injury, and 4 cases of fall from height injury. According to Garden classification, the femoral neck fracture was classified as type Ⅲ in 3 cases, type Ⅳ in 15 cases, and all patients were type Ⅲ according to Pauwels classification. The time from injury to operation was 1-5 days, with an average of 2.3 days. The fracture healing time and complications were recorded. The quality of fracture reduction was evaluated by Garden index immediately after operation; at last follow-up, the degree of femoral neck shortening was determined by Zlowodzki method, Harris score was used to evaluate hip function. RESULTS: The operation time was 62-98 minutes (mean, 75 minutes); intraoperative blood loss was 101-220 mL (mean, 153 mL). Cannulated screws guide wire was inserted 3-5 times (mean, 4 times). Intraoperative fluoroscopy was performed 9-21 times (mean, 15 times). The hospital stay was 5-11 days (mean, 7.2 days). All the patients were followed up 12-40 months with an average of 17.3 months. There was no postoperative complication such as accumulated pneumonia, lower extremity deep venous thrombosis, nail cutting, nail withdrawal, internal fixation fracture, and so on. There was no fracture nonunion and osteonecrosis of the femoral head during the follow-up; the fracture healing time was 7-15 weeks, with an average of 12.1 weeks. The quality of fracture reduction was evaluated immediately after operation, the results were grade Ⅰ in 15 cases and grade Ⅱ in 3 cases. At last follow-up, there were 2 cases with femoral neck shortening less than 5 mm and 1 case with 5-10 mm. The incidence of femoral neck shortening was 16.7%. The Harris score of hip joint was 73-97, with an average of 93.5; among them, 12 cases were rated as excellent, 3 cases as good, and 3 cases as fair, with an excellent and good rate of 83.3%. CONCLUSION: For the treatment of unstable femoral neck fracture with posteromedial comminutations, cannulated screws and medial bracing plate combined with bone allograft are dramatically effective due to earlier weight bearing, faster fracture healing, and better hip function recovery.

[Accuracy of free-hand thoracic pedicle screw placement in severe idiopathic scoliosis via CT scan].

OBJECTIVE: To analyze the accuracy of free-hand thoracic pedicle screw placement in severe idiopathic scoliosis via CT scan. METHODS: Twenty patients with complete CT data were chosen out of 58 patients of severe idiopathic scoliosis from June 1996 to December 2006. The Cobb angle of the main thoracic curve was from 82 degree to 142 degree (96.3 degree +/- 14.3 degree). The kyphotic angle in the main curve was 66.2 degree +/- 12.4 degree. The placement of thoracic pedicle screw was completed free-handedly, and the accuracy of screws placement was evaluated with CT thin-slice scan postoperatively. RESULTS: Altogether 174 thoracic pedicle screws were inserted, 157 (90.2%) of which were fully contained within the cortical boundaries of the pedicle.The other 17 screws (9.8%) were misplaced in 9 patients: 11 screws (6.8%) were lateral, 9 of which had a breach 0.05). There was no neural complication in all patients. CONCLUSION: It is fairly accurate place thoracic pedicle screw in severe idiopathic scoliosis free-handedly, with some misplacements.

One-stage posterior approach for treating multilevel noncontiguous thoracic and lumbar spinal tuberculosis.

OBJECTIVES: Multilevel noncontiguous thoracic and lumbar spinal tuberculosis (MNST) is a relatively rare entity. The objective of this retrospective study was to investigate whether a technique involving a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, is effective for treating MNST. METHODS: Thirteen patients, with an average age of 40.69 (18-67) years, who had MNST and were surgically treated in our department from January 2008 to October 2013, were reviewed. RESULTS: The average follow-up time was 37.54 ± 10.49 (19-58) months. The mean Cobb angle range was 15.69° ± 00A09.09° (-3° to 33°). The mean erythrocyte sedimentation rate (ESR) was 47.69 ± 9.30 mm/h (range 30-62 mm/h) before the operation. Neurological deficits were evaluated using the Frankel grade system. The mean Cobb angle decreased to 6.92° ± 3.93° postoperatively. Three months after the operation, the Cobb angle was 7.54° ± 4.35°, and the average ESR was 10.38 ± 4.54 mm/h that was normal for all cases in this retrospective observational study. Solid fusion was achieved in all cases. No severe complications occurred. CONCLUSIONS: The study demonstrated that a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, was effective for treating MNST.

[Selective resection of the branches of the two dorsal penile nerves for primary premature ejaculation].

OBJECTIVE: To evaluate the safety and effect of selective resection of the branches of the two dorsal penile nerves in the treatment of primary premature ejaculation (PPE). METHODS: From September 2003 to December 2006, 483 PPE patients aged 21-71 years (mean 32) underwent selective resection of the branches of the two dorsal penile nerves, with only 2 of the branches reserved, 3 resected in 89 cases, 4 in 183, 5 in 125, 6 in 38, 7 in 32, 8 in 12, 9 in 3 and 10 in 1. The patients could have sexual intercourse 4 weeks after the operation and were followed up for 3-36 months. RESULTS: No infection, hemorrhage and erectile dysfunction were observed. Decreased penile sensibility was noted in all the patients, obviously prolonged ejaculation latency in 352, improvement in 93 and failure in 38, with a total effectiveness rate of 92.13%. CONCLUSION: Selective resection of the branches of the two dorsal penile nerves, which can definitely reduce the sensivity of the penis, is a safe and effective surgical option for the treatment of PPE.

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.

A retrospective study comparing percutaneous and open pedicle screw fixation for thoracolumbar fractures with spinal injuries.

BACKGROUND: The purpose of this study was to evaluate the effectiveness between percutaneous and open pedicle screw fixation for treating thoracolumbar fractures with spinal injuries. METHODS: A total of 105 patients with thoracolumbar fractures and spinal injuries were divided into a percutaneous pedicle screw fixation (PPSF) group with 56 patients, who underwent percutaneous pedicle screw fixation, and an open pedicle screw fixation (OPSF) group with 49 patients, who underwent open pedicle screw fixation in accordance with the treatment project. Relative operation indexes, radiologic, and effectiveness parameters were assessed and compared between the 2 groups. RESULTS: Demographic and clinical features including age, body mass index, gender, fracture level, fracture classification, and Frankel grade in both groups were not significantly different (all P >.05). The PPSF group exhibits significantly lower operation time, intraoperative blood loss, postoperative drainage volume, and hospital stay on average compared with the OPSF group (all P < .05). Besides, the average postoperative radiologic parameters, including Cobb angle (CA), vertebral wedge angle (VWA), vertebral front height percentage (VFHP), and sagittal index (SI), in both the groups were not significantly different (all P > .05). Nevertheless, both visual analogue scale (VAS) and Oswestry disability index (ODI) after surgery decreased more substantially in the PPSF group than in the OPSF group (all P < .05) while no significant difference in VAS scores or ODI during the last follow-up period was demonstrated in both the groups (both P > .05). Frankel classifications were stimulated in both the groups during the last follow-up period. CONCLUSION: PPSF has a smaller incision, less intraoperative blood loss, shorter recovery time, higher safety measures on average compared with OPSF with respect to managing thoracolumbar fractures with spinal injuries.

A new photoelectric ink based on nanocellulose/CdS quantum dots for screen-printing.

CdS quantum dots with excellent photoelectrical properties embedded in nanocellulose could be exploited for use in photoelectrical ink. In this work, nanocellulose/CdS quantum dot composites were fabricated by controlling the carboxylate content of the nanocellulose and the molar ratio of Cd(2+)/-COOH. New photoelectric inks were prepared based on the composites, in which the CdS quantum dots acted as the pigment and the nanocellulose as the binder. The results of the photocurrent of the composites showed that the photocurrent could be tailored by the carboxylate content and the molar ratio of Cd(2+)/-COOH. And the photocurrent could be as high as 2µA. The surface tension of the photoelectric ink was 27.80±0.03mN/m and its viscosity was 30.3mPas. The photoelectric ink was stable with excellent fluidity and rheology, it could therefore be applied to screen-printing and three-dimensional (3D) printing.

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.

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.

Development of Injectable Citrate-Based Bioadhesive Bone Implants.

Injectable bone implants have been widely used in bone tissue repairs including the treatment of comminuted bone fractures (CBF). However, most injectable bone implants are not suitable for the treatment of CBF due to their weak tissue adhesion strengths and minimal osteoinduction. Citrate has been recently reported to promote bone formation through enhanced bioceramic integration and osteoinductivity. Herein, a novel injectable citrate-based mussel-inspired bioadhesive hydroxyapatite (iCMBA/HA) bone substitute was developed for CBF treatment. iCMBA/HA can be set within 2-4 minutes and the as-prepared (wet) iCMBA/HA possess low swelling ratios, compressive mechanical strengths of up to 3.2±0.27 MPa, complete degradation in 30 days, suitable biocompatibility, and osteoinductivity. This is also the first time to demonstrate that citrate supplementation in osteogenic medium and citrate released from iCMBA/HA degradation can promote the mineralization of osteoblastic committed human mesenchymal stem cells (hMSCs). In vivo evaluation of iCMBA/HA in a rabbit comminuted radial fracture model showed significantly increased bone formation with markedly enhanced three-point bending strength compared to the negative control. Neovascularization and bone ingrowth as well as highly organized bone formation were also observed showing the potential of iCMBA/HA in treating CBF.