Objective To investigate the causes and managements of acetabular fracture during primary total hip arthroplasty (THA). Methods Between May 2005 and July 2008, 9 patients (9 hi ps) suffered from acetabular fractures during primary THA. There were 1 male and 8 females with an average age of 63.3 years (range, 41-73 years), including 4 cases of developmental dysplasia of the hip, 2 cases of rheumatoid arthritis, 1 case of old femoral neck fracture, 1 case of avascular necrosis of femoral head, and 1 case of ankylosing spondyl itis. Three left hips and 6 right hips were involved. The preoperative Harris score was 40.4 ± 2.9. All the patients underwent cementless THA. Among nine acetabular fractures, 8 fractures were stable (2 anterior wall fractures and 6 posterior wall fractures), which were fixed by additional augmentation screws in 7 cases and accepted no special treatment in 1 case; 1 fracture was unstable (posterior wall fracture with posterior column incomplete fracture), which was treated by bone grafting and additional screws. Results The postoperative X-ray films showed that the position of the prosthesis were favorable. All incisions healed by first intention without early compl ication. Nine patients were followed up 1-4 years (mean, 2 years and 7 months). The Harris score was 87.8 ± 3.9 at last follow-up, showing significant difference when compared with the preoperative score (t=44.904, P=0.000). The X-ray films showed fracture heal ing at 8 weeks. No loosening occurred. Conclusion When primary THA is performed, the preoperative X-ray film should be studied and measured carefully, operation should be accurate and violence should be avoided. The diameter of the acetabular component should be equal to the diameter of a drill or not larger than 2 mm. In patients with severe osteoporosis, the diameter of the acetabular components should be the same diameter as a drill and additional screws are used to fix, or cemented cup is used. Once an acetabular fracture occurs during the primary THA, additional screw or bone grafting with additional screws should be chosen according to the fracture type and stabil ity, and good cl inical results can be expected.
Objective To optimize image quality and radiation dose of infant chest digital radiography and to explore feasibility of reducing tube voltage and adjusting according to infant chest area. Methods 0 to 3-year-old infants were randomly divided into two average groups of 0- and 1-3 year-old, and then each age group was randomly assigned to optimization and control groups in digital radiography. Measurement of radiation dose used dose area product (DAP). Mean DAP between groups was compared by using t test, and the image quality of optimization was compared by rank sum test. Results A total of 400 cases of 0 to 3-year-old infants were identified, and finally 391 cases of infants anteroposterior chest image were included, including 196 cases in the optimization group (0-years: n=91; 1-3 years: n=105) and 195 cases in the control group (0-years: n=103; 1-3 years: n=92). The results showed: there were significant differences in the mean DAP in 0-years, 1-3 years and total infants between the optimization group and the control group (all P valuelt;0.05). The DAP of the optimization group was lower, and reduction of DAP was approximately 21.6% compared to the control subject. The Wilcoxon signed-rank test showed the difference of subjective evaluation of image quality was significantly different (P=0.000). High-quality image of the optimization group increased approximately 43.9% more than control subject. Conclusion Reducing tube voltage and adjusting according to infants chest area can not only reduce the radiation dose but also improve image quality in digital radiography.