ABSTRACT
Objective To study the influence of the distance of displaced fragment on the union of diaphysis fracture. Methods A wedge-shaped bone fragment was taken from central radial of the right forelimb of 120 New Zealand white rabbits for estabhshment of experimental animal model. The bone fragment was fixed to the main bone with two Kirschner wires, with certain space between bone fragment and the main bone. Then, the rabbits were divided into five groups, ie, Group A (in situ fixation),Group B (the space was 1/5 diameter of the radial shaft), Group C (the space was 2/5 diameter of the radial shaft), Group D (the space was 3/5 diameter of the radial shaft), Group E (the space was 4/5 diameter of the radial shaft). The animals were killed at 2, 4, 6, 8 weeks after operation. X-ray photos were taken to observe the fracture healing and the improved Gary X-ray used for scoring. HE staining after tissue section was employed to observe the histomorphological changes of fracture healing. Immunohistochemical method was used to determine expression of BMP-2. Results X-ray findings showed insignificant statistical difference between Group A and Group B, delayed union in Groups C and D and nonunion of bone absorption in Group E. Morphological observation showed same change in fracture site in Groups A and B lout significant late in emergence, formation and remodeling of the callus in the other groups compared with Group A, mainly with delayed fracture union or nonunion. There was no statistical difference in expression of BMP-2 between Group B and Group A (P ＞ 0. 05), but there was statistical significance in Groups C, D and E compared with Group A at 2 weeks (P ＜0.01). There was statistical difference between Group E and Group A at 4 weeks (P ＜0. 01) but no statistical difference at 6 and 8 weeks between either two groups (P ＞ 0. 05). Conclusions The distance of displaced fragment will influence fracture healing. The larger distance of the displaced fragment will beget more obvious influence on fracture healing. When the distance is more than 2/5 diameter of the bone shaft, the fracture will present union disorder.
ABSTRACT
Objective To explore the imaging findings and diagnostic values of X-ray, CT, MR,and ultrasonography in traumatic knee joints hemarthrosis and lipohemarthrosis. Methods Traumatic knee joints hemarthrosis (12 knees) and lipohemarthrosis (18 knees) proved by operation (27 knees) or puncturation (3 knees) were included in the study. Horizontal-beam plain radiographs (16 knees), CT (30 knees), MRI (30 knees) and ultrasonography (24 knees) in supine position were investigated. Results (1)supine position horizontal-beam plain radiographs: Fat-liquid layer was found in 8 cases of lipohemarthrosis. Dense supragenual bursa was found in 1 case of lipohemarthrosis and 7 cases of hemarthrosis. Fracture (13 knees) was diagnosed correctly. (2) CT findings: double fluid-fluid layer was found in 11 of all 18 cases, and single fluid-fluid layer was found in 7 of 11 cases of lipohemarthrosis. Single fluid-fluid layer was found in 3 of 12 cases of hemarthrosis. Isodensity was detected in 9 cases, and high-density blood clot was found in 4 cases. Fracture (30 knees) was diagnosed correctly. (3) MRI findings: in 12 of 18 cases of lipohemarthrosis, double fluid-fluid layer was shown including supernatant layer as short T1, long T2signal and low signal after fat-suppression, middle layer as long T1, long T2 signal and high signal after fat-suppression, and dependent layer as iso-T1, iso-T2 and slight high signal after fat-suppression. Single fluid-fluid layer was seen in 6 cases, only had aforementioned upper and under layer.Only aforementioned supernatant layer and dependent layer were seen in 12 cases of hemarthrosis. 4 cases showed entire blood clot in fluid, T1WI showed middle signal or center iso-signal accompanied with peripheral high signal ring, and fat-suppression imaging showed high signal. T2WI and fat-suppressionimaging showed middling or high signal accompanied with peripheral low signal ring. Fracture (30 knees) was diagnosed correctly. (4) Ultrasound findings: In 10 of 14 cases of lipohemarthrosis, double fluid-fluid level was shown, supernatant layer as equal echo, middle layer as echoless, and dependent layer as cloudy echo. Four cases with single fluid-fluid level only showed aforementioned upper and under layer. Three of 10 cases of hemarthrosis showed single fluid-fluid level, only showing aforementioned upper and under layer,and 7 cases showed cloudy echo and float. In 3 cases the fluid blood clot showed irregular shape low-equal echo bolus. No fracture hne was found. Conclusions CT can clearly detect fracture line, hemarthrosis and lipohemarthresis, and can substitute plain radiography. MRI is the best way to diagnose hemarthresis and lipohemarthrosis. Ultrasonography can be used in diagnosing hemarthresis and lipohemarthrosis but not helpful in the diagnosis of fracture.