A new navigational apparatus for fixation of acetabular posterior column fractures with percutaneous retrograde lagscrew: Design and application.

The purpose of this study was to analyze the feasibility and accuracy of a newly developed guide apparatus for the percutaneous retrograde lag screw fixation of posterior column of acetabular fractures. 3D pelvic models were reconstructed from the helical computed tomographic data of 33 adult patients using the Mimics 10.01 software. The virtual cylindrical implants were placed along a line passing through the central point of the ischial tuberosity and the midpoint between the most prominent point of anterior superior iliac spine and that of posterior superior iliac spine. Some anatomical parameters were then measured, based on which a guide apparatus was developed, and its safety and accuracy were experimentally validated with pelvic and cadaveric specimens. The screws were successfully placed in all of the 66 hemipelves. There was a significant difference between the male and female groups in the AB distance (156.26 ±â€Š7.28 mm and 151.38 ±â€Š8.11 mm), OI distance (139.53 ±â€Š7.56 mm and 125.15 ±â€Š11.17 mm), and diameter (12.19 ±â€Š1.97 mm and 10.19 ±â€Š2.14 mm) of the virtual cylindrical implants. This guide apparatus was proved effective for percutaneous retrograde lag screw fixation of posterior column acetabular fractures by the experiments with the pelvic and cadaveric specimens. Screw fixation of posterior column fractures via OI is safe and feasible. We designed a new percutaneous retrograde screw fixation guide apparatus to assist internal fixation of posterior column acetabular fracture.

[Clinical study on negative pressure closed drainage combined with vancomycin loaded calcium sulfate and autogenous bone in the treatment of chronic osteomyelitis].

OBJECTIVE: To study the clinical effects of negative pressure closed drainage combined with vancomycin loaded calcium sulfate and autogenous bone in the treatment of chronic osteomyelitis. METHODS: From June 2013 to December 2016, there were 35 cases of chronic osteomyelitis patients in our department, including 23 males and 12 females, ranging in age from 11 to 65 years old, with an average of 34 years old. The course of disease ranged from 8 to 46 months, with an average of 26 months. All patients were chronic osteomyelitis caused by open wounds. The lesions had recurrent redness and swelling and purulent skin perforation. Thirty-two patients had positive results in bacterial culture of sinus secretions, and 3 patients had negative results. Imaging examination showed the lesions of bone destruction, bone defects, surrounded by bone hyperplasia sclerosis. At the first stage, complete debridement was performed to remove necrotic tissues and inflammatory tissues; and the dressing of negative pressure closed drainage was used to completely cover the wound so as to promote the repair of the wound. At the second stage, the vancomycin loaded, calcium sulfate and autogenous iliac cancellous bone were mixed into the bone graft complex to evenly fill the lesions. The healing of the wound was observed and X-ray examination of the lesion was carried out to observe the absorption of calcium sulfate and the growth of new bone. RESULTS: Twenty-six patients underwent debridement and negative pressure closed drainage on time, 6 patients 2 times, and 3 patients 3 times. Thirty-two patients had incisions healed with grade A; 2 patients had incisions healed with grade B, and got completely healing after anti-infection, and wound dressing treatment; 1 patient had an incision healed with grade C, and got normal healing after re-debridement at the 4th week after operation. All patients did not have skin redness and ulceration again. X-ray imaging showed that the implanted calcium sulphate was absorbed gradually around 4 weeks, new bone was formed at 8 weeks, and bone defects in the lesions area were healed completely at 6 months to 2 years. CONCLUSIONS: Negative pressure closed drainage combined with vancomycin loaded calcium sulfate and autogenous bone in the treatment of chronic osteomyelitis is a good and reliable method, worthy of clinical promotion.

Enhancement of bone formation with a synthetic matrix containing bone morphogenetic protein-2 by the addition of calcium citrate.

PURPOSE: The aim of the study was to test whether calcium citrate combined with rhBMP-2 was able to enhance bone regeneration compared with a matrix containing only rhBMP-2. METHODS: In each of experimental mice, one cylinder of calcium citrate-rhBMP-2 or rhBMP-2 alone was implanted into the thigh muscle pouches of the mouse. The following two treatment modalities were randomly allocated: (1) empty control with rhBMP-2 alone in a gelatin matrix and (2) a gelatin matrix including both calcium citrate and BMP-2. After several weeks, bone granules were obtained by histological analysis. RESULTS: Histomorphometric analysis showed the greatest amount of newly formed bone was observed in the group that contained 10.0 mg calcium citrate with 2.0 mg rhBMP-2 (p < 0.05). Quantitative histomorphometry revealed in the calcium citrate-rhBMP-2 group an obvious increase in the fractional area and the average new bone mineral density of newly formed bone at 2, 4 and 6 weeks than in the rhBMP-2 group (p < 0.05). At 2 weeks time-point, the mature cancellous bone had formed in the calcium citrate-rhBMP-2 group. CONCLUSIONS: From this study, it can be concluded that calcium citrate combined with rhBMP-2 significantly enhances bone regeneration in muscle. This synthetic gelatin matrix containing calcium citrate/gelatin granules fulfils a number of criteria required for an ideal carrier system for rhBMP-2. The calcium ions that calcium citrate releases into the surrounding environment can activate bone formation when used as part of a combination of calcium citrate and BMP-2.