[Minimally invasive osteotomy with absorbable screws in treating hallux valgus deformity].

OBJECTIVE: To evaluate clnical effect of minimally invasive osteotomy with absorbable screws in treating hallux valgus deformity. METHODS: Clnical data of 31 patients with hallux valgus deformity were retrospective analyzed from January 2019 to December 2020, and divided into absorbable screws group (17 patients) and titanium cannulated screw group (14 patients). In absorbable screws group, there were 1 male and 16 females aged from 32 to 72 years old with an average of (54.53±12.12) years old;6 patients on the left side, 5 on bilateral and 6 on the right side;1 patient was mild, 11 moderate and 5 severe;treated with minimally invasive osteotomy and fixation of absorbable screws. In titanium cannulated screw group, there were 2 males and 12 females aged from 18 to 71 years old with an average of (47.57±15.68) years old;4 patients on the left side, 4 on bilateral and 6 on the right side;1 patient was mild, 9 moderate and 4severe;treated with minimally invasive osteotomy and fixation of titanium cannulated screw. Complications between two groups were observed, changes of hallux valgus angle (HVA)and intermetatarsal angle (IMA)were detected and compared before and after operation at 12 months, American Orthopedic Foot and Ankle Society(AOFAS) and visual analogue scale(VAS) before and after operation at 12 months were also compared. RESULTS: All 31 patients were followed up from 13 to 20 months with an average of (16.61±2.47) months. Patients in absorbable screws group were followed up from 14 to 20 months with an average of (16.88±2.80) months, while patients in titanium cannulated screw group were followed up from 13 to 19 months with an average of (16.29±2.05) months;there was no difference between two groups(P>0.05). One patient in absorbable screws group occurred numbness around incision, 3 patients in titanium cannulated screw group occurred complications, including numbness around incision in 1 patient, skin irritation due to internal fixation in 1 patient, and recurrence in 1 case;there was no statistic difference between two groups (χ2=1.651, P=0.199). There were no statistic difference in HVA and IMA between two groups before and after operation at 12 months(P>0.05). There were no statistic difference between two groups in AOFAS and VAS before and after operation at 12 months(P>0.05). CONCLUSION: Compare with mainstream fixation with titanium hollow screw after minmally invasive osteotomy, fixation with absorbable screw could achieve comparable clinical outcome on the basis of images and function evaluation.

Multi-stage controllable degradation of strontium-doped calcium sulfate hemihydrate-tricalcium phosphate microsphere composite as a substitute for osteoporotic bone defect repairing: degradation behavior and bone response.

Various requirements for the repair of complex bone defects have motivated to development of scaffolds with adjustable degradation rates and biological functions. Tricalcium phosphate (TCP) and calcium sulfate are the most commonly used bone repair materials in the clinic, how to better combine TCP and calcium sulfate and play their greatest advantages in the repair of osteoporotic bone defect is the focus of our research. In this study, a series of scaffolds with multistage-controlled degradation properties composed of strontium-doped calcium sulfate (SrCSH) and strontium-doped tricalcium phosphate (Sr-TCP) microspheres scaffolds were prepared, and their osteogenic activity,in vivodegradation and bone regeneration ability in tibia of osteoporotic rats were evaluated.In vitrostudies revealed that different components of SrCSH/Sr-TCP scaffolds significantly promoted the proliferation and differentiation of MC3T3-E1 cells, which showed a good osteogenic induction activity.In vivodegradation results showed that the degradation time of composite scaffolds could be controlled in a large range (6-12 months) by controlling the porosity and phase composition of Sr-TCP microspheres. The results of osteoporotic femoral defect repair showed that when the degradation rate of scaffold matched with the growth rate of new bone, the parameters such as bone mineral density, bone volume/total volume ratio, trabecular thickness, angiogenesis marker platelet endothelial cell adhesion molecule-1 and new bone formation marker osteocalcin expression were higher, which promoted the rapid repair of osteoporotic bone defects. On the contrary, the slow degradation rate of scaffolds hindered the growth of new bone to a certain extent. This study elucidates the importance of the degradation rate of scaffolds for the repair of osteoporotic bone defects, and the design considerations can be extended to other bone repair materials, which is expected to provide new ideas for the development of tissue engineering materials in the future.

Enhanced bone formation by strontium modified calcium sulfate hemihydrate in ovariectomized rat critical-size calvarial defects.

The development of a new generation of biomaterials with high osteogenic ability for treatment of osteoporotic fractures is being intensively investigated. The objective of this paper was to investigate new bone formation in an ovariectomized rat (OVX rat) calvarial model of critical size bone defects filled with Sr-containing α-calcium sulfate hemihydrate (SrCSH) cement compared to an α-calcium sulfate hemihydrate (α-CSH) cement and empty defect. X-ray diffraction analysis verified the partial substitution of Sr2+ for Ca2+ did not change the phase composition of α-CSH. Scanning electron microscopy showed that Sr-substituted α-CSH significantly increased the surface roughness. The effects of Sr substitution on the biological properties of SrCSH cement were evaluated by adhesion, proliferation, alkaline phosphatase (ALP) activity of osteoblast-like cells MC3T3-E1. The results showed that SrCSHs enhanced MC3T3-E1 cell proliferation, differentiation, and ALP activity. Furthermore, SrCSH cement was used to repair critical-sized OVX rat calvarial defects. The in vivo results revealed that SrCSH had good osteogenic capability and stimulated new blood vessel formation in a critical sized OVX calvarial defect within 12 weeks, suggesting that SrCSH cement has more potential for application in bone tissue regeneration.

A reformative shear precipitation procedure for the fabrication of vancomycin-loaded poly(lactide-co-glycolide) microspheres.

This study reports the encapsulation of vancomycin, as a model hydrophilic drug, into poly(lactide-co-glycolide) microspheres using a novel reformative shear precipitation procedure. In contrast to the external aqueous phase used in the conventional microencapsulation technique based on emulsion solvent evaporation/extraction, the reformative shear precipitation procedure explored in this study uses a shear medium composed of glycerol as the viscous medium and ethanol as polymer antisolvent, which is relatively immiscible with the hydrophilic drug. This limits drug diffusion and leads to rapid microsphere solidification, which allows a large proportion of the hydrophilic drug to be encapsulated within the microspheres. The influence of various processing parameters, including polymer concentration, volume ratio of ethanol to glycerol in the shear medium, volume of aqueous drug solution, initial drug loading, and injecting rate of the drug-polymer emulsion, on the encapsulation efficiency and characteristics of resulting microspheres were investigated. The morphology and release characteristics, as well as mechanical, in vitro and in vivo behaviour of vancomycin-loaded poly(lactide-co-glycolide) microspheres prepared using the novel procedure were also investigated. The results demonstrated that the reformative shear precipitation procedure could achieve the loading of hydrophilic drugs into poly(lactide-co-glycolide) microspheres with high encapsulation efficiency, and the success of the procedure was largely influenced by the volume ratio of ethanol to glycerol in the shear medium. Vancomycin-loaded poly(lactide-co-glycolide) microspheres prepared using this procedure demonstrated favourable mechanical characteristics, antibacterial activity, and in vivo degradation behaviour which suggested their suitability for use as a sustained delivery system.

Femoral version, neck-shaft angle, and acetabular anteversion in Chinese Han population: a retrospective analysis of 466 healthy adults.

Anatomic data regarding femoral version, neck-shaft angle, and acetabular anteversion are still limited in Chinese Han adult population. The aim of this study was to investigate the effects of age, sex, and body laterality on the 3 important anatomic indicators in Chinese Han healthy adults. Measurements were performed independently by 3 experienced observers using the picture archiving and communication system (PACS) in healthy adults who had received imaging tests of the femur and acetabulum between January 2009 and October 2014. Relevant data were measured and analyzed. A total of 466 adults (353 males and 113 females) were included. The mean femoral version, neck-shaft angle, and acetabular anteversion for all were 10.62, 133.02, and18.79, respectively. Age-based analysis showed that adults younger than 60 years had a significantly higher neck-shaft angle (P < 0.001) but a significantly lower acetabular anteversion (P < 0.001) than those older than 60 years. Sex-based analysis revealed that females had significantly higher values of femoral version (P < 0.001) and acetabular anteversion (P < 0.001) than males. Laterality-based analysis found the left side had a significantly lower acetabular anteversion (P < 0.001) than the right side. Outcomes of multiple linear regression analysis indicated that femoral version may be associated with sex (P < 0.001) but not age (P = 0.076) or laterality (P = 0.430), neck-shaft angle may be associated with age (P < 0.001) but not sex (P = 0.378) or laterality (P = 0.233), and acetabular anteversion may be associated with age (P < 0.001) and sex (P < 0.001) but not laterality (P = 0.060). In this representative Chinese cohort, neck-shaft angle may decrease, whereas acetabular anteversion may increase with age, females may have higher values of femoral version and acetabular anteversion than males, and the right body side may have a higher value of acetabular anteversion than the left side.