ABSTRACT
Objective To investigate the setting property and compressive strength of β-TCP (β-tricalcium phosphate)/α-CSH (α-calcium sulphate hemihydrate) combined bone graft. Method β TCP/α CSH combined bone graft and distilled water were mixed with different ratio: 1 g∶0.1 mL、1 g∶0.2 mL、1 g∶0.3 mL、1 g∶0.4 mL、1 g∶0.5 mL, respectively. The initial setting time (Ti), final setting time (TF), compressive strength were recorded, and the X-ray diffraction (XRD) and the scanning electron microscope (SEM) were examined. Results The initial and final setting time of combined bone graft increased along with the increase of solid/liquid ratio. The Ti and TF were (4.6±1.3) min and (13.1±2.9) min respectively when the solid/liquid ratio was 1 g∶0.2 mL. The average compressive strength was 7.86 MPa in one day after setting, which was about two times higher than that of β-TCP alone. The XRD results showed that no other materials were produced except that α-CSH was transformed to CSD in the setting process. The SEM results indicated that thick CSD granules were adhered to the porous surfaces of β-TCP granules after setting. Conclusions The setting time and compressive strength of β-TCP/α-CSH combined bone graft could be adjusted by the different solid/liquid ratio.
ABSTRACT
<p><b>OBJECTIVE</b>To study the prevalence of chondromalacia patella among college students and the correlation with sports injury.</p><p><b>METHODS</b>354 students from gymnastic department and 429 from nongymnastic department with knee joint pain were selected. 184 students from gymnastic department and 342 from nongymnastic department were checked randomly by a surgeon. 77 patients (37 males, 40 females) from gymnastic department and 119 patients (62 males, 57 females) from nongymnastic department were diagnosed as chondromalacia patellae. The amount of exercise and the occurrence of sports injury were investigated in each student. All data were analyzed with SPSS 10.0 statistical software.</p><p><b>RESULTS</b>The prevalence of chondromalacia patella was 20.1% in female students and 11.6% in male students from gymnastic department, and 5.61% in female students and 4.92% in male students from nongymnastic department. The amount of exercise and the occurrence of sports injury to the knee joint in students from gymnastic department were greater than those from nongymnastic department.</p><p><b>CONCLUSIONS</b>In both female and male students, the prevalence of chondromalacia patella is higher in gymnastic department than nongymnastic department. Sports injury is an important cause of chondromalacia patella.</p>