Fixation Of Cancellous Bone Osteotomies Research Articles

Fixation of experimental osteotomies with bioabsorbable SR-polylactide–polyglycolide (80/20) polymeric rods

Self-reinforced polylactide-polyglycolide (80/20) composite rods, 2 mm in diameter and 36 mm in length, were implanted into the dorsal subcutaneous tissue of 20 rabbits. Osteotomies of the distal femur were fixed with these rods (2x15 mm) in the rabbits. The follow-up times varied from 3 to 104 weeks. After sacrifice, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, microradiographic, oxytetracycline-fluorescence, and histomorphometrical studies of the osteotomized and intact control femora were performed. After 6 weeks the mechanical properties had decreased significantly, but osteotomies had healed uneventfully. The present investigation showed that the mechanical strength and fixation properties of SR-Polylactide-glycolide (80/20) rods are suitable for fixation of cancellous bone osteotomies in rabbits provided that the operative technique is correct. The present article is the first report on the application of these rods for fixation of cancellous bone osteotomies.

Fixation of distal femoral osteotomies with self-reinforced poly(L/DL)lactide 70 : 30 and self-reinforced poly(L/DL)lactide 70 : 30/bioactive glass composite rods. An experimental study on rabbits

Two self-reinforced poly(L/DL)lactide 70 : 30 or self-reinforced poly(L/DL)lactide 70 : 30/bioactive glass (SR-P(L/DL)LA/bioactive glass) composite rods (2 mm × 40 mm) were implanted into the dorsal subcutaneous tissue and osteotomies of the distal femur were fixed with these rods (2 mm × 26 mm) in 36 rabbits. The follow-up times varied from 3 to 100 weeks. After the animals were killed, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. After 12 weeks the SR-P(L/DL)LA rods had fragmented into pieces and the mechanical properties could not be measured. The SR-P(L/DL)LA/bioactive glass rods lost their mechanical properties slower, and at 24 weeks the bending strength had decreased by 39% and the shear strength by 50%. After that the mechanical properties of the SR-P(L/DL)LA/bioactive glass rods could not be measured. All osteotomies healed well, and no gross signs of inflammatory reactions were observed. One slight displacement was seen in the three-week follow-up group with SR-P(L/DL)LA rods. Signs of resorption of the implants were seen after 48 weeks in the SR-P(L/DL)LA group and after 24 weeks in the SR-P(L/DL)LA/bioactive glass group. The SR-P(L/DL)LA/bioactive glass rods were almost totally resorbed from the bone at 100 weeks. The present investigation showed that the mechanical strength and fixation properties of the SR-P(L/DL)LA and the SR-P(L/DL)LA/bioactive glass composite rods are suitable for fixation of cancellous bone osteotomies in rabbits.

Fixation of distal femoral osteotomies with self-reinforced polymer/bioactive glass rods: an experimental study on rabbits

Two self-reinforced poly(desamino tyrosyl–tyrosine ethyl ester carbonate), poly(DTE carbonate) or self-reinforced poly(DTE carbonate)/bioactive glass rods, (2 mm by 40 mm) were implanted into the dorsal subcutaneous tissue and osteotomies of the distal femur were fixed with these rods (2 mm by 26 mm) in 36 rabbits. The follow-up times varied from three to 100 weeks. After sacrifice, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. The initial mechanical properties were higher with the SR-poly(DTE carbonate) rods, but the SR-poly(DTE carbonate)/bioactive glass rods lost their mechanical properties slower. At 100 weeks the bending strength had decreased to 21% of the initial value with the SR-poly(DTE carbonate) rods and to 49% with the SR-poly(DTE carbonate)/bioactive glass rods. The shear strength had decreased to 10% with the SR-poly(DTE carbonate) rods and to 23% of the initial value with the SR-poly(DTE carbonate)/bioactive glass rods. Two slight displacements and one delayed union and one failure of fixation were seen in the SR-poly(DTE carbonate) group. In the SR-poly(DTE carbonate)/bioactive glass group five delayed unions and seven slight displacements were seen. No signs of osteolysis or foreign body reactions were observed. Signs of resorption of the implants were seen at 100 weeks in the SR-poly(DTE carbonate)/bioactive glass group. The present investigation showed that the mechanical strength and fixation properties of SR-poly(DTE carbonate) and SR-poly(DTE carbonate)/bioactive glass rods are suitable for fixation of cancellous bone osteotomies in rabbits.

Fixation of distal femoral osteotomies with self-reinforced polymer/bioactive glass rods: an experimental study on rabbits

Two self-reinforced poly(desamino tyrosyl–tyrosine ethyl ester carbonate), poly(DTE carbonate) or self-reinforced poly(DTE carbonate)/bioactive glass rods, (2 mm by 40 mm) were implanted into the dorsal subcutaneous tissue and osteotomies of the distal femur were fixed with these rods (2 mm by 26 mm) in 36 rabbits. The follow-up times varied from three to 100 weeks. After sacrifice, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. The initial mechanical properties were higher with the SR-poly(DTE carbonate) rods, but the SR-poly(DTE carbonate)/bioactive glass rods lost their mechanical properties slower. At 100 weeks the bending strength had decreased to 21% of the initial value with the SR-poly(DTE carbonate) rods and to 49% with the SR-poly(DTE carbonate)/bioactive glass rods. The shear strength had decreased to 10% with the SR-poly(DTE carbonate) rods and to 23% of the initial value with the SR-poly(DTE carbonate)/bioactive glass rods. Two slight displacements and one delayed union and one failure of fixation were seen in the SR-poly(DTE carbonate) group. In the SR-poly(DTE carbonate)/bioactive glass group five delayed unions and seven slight displacements were seen. No signs of osteolysis or foreign body reactions were observed. Signs of resorption of the implants were seen at 100 weeks in the SR-poly(DTE carbonate)/bioactive glass group. The present investigation showed that the mechanical strength and fixation properties of SR-poly(DTE carbonate) and SR-poly(DTE carbonate)/bioactive glass rods are suitable for fixation of cancellous bone osteotomies in rabbits.

Fixation of distal femoral osteotomies with self-reinforced poly(L/DL)lactide 70:30/bioactive glass composite rods. An experimental study on rats.

Self-reinforced poly(L/DL)lactide 70:30/bioactive glass [SR-P(L/DL)LA/bioactive glass] composite rods, 2 mm in diameter and 36 mm in length, were implanted into the dorsal subcutaneous tissue of 16 rats. Osteotomies of the distal femur were fixed with these rods (2 x 15 mm) in 64 other rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests, and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. At 24 weeks the mechanical properties had decreased significantly. Thirty-nine osteotomies healed uneventfully. One of the 64 evaluated osteotomies showed signs of infection at six weeks, and there were 19 non-unions and six delayed unions. In 20 operations the fixation was loose and out of these 14 non-unions were observed. No gross signs of inflammatory or foreign-body reactions were observed. The present investigation showed that the mechanical strength and fixation properties of SR-P(L/DL)LA/bioactive glass composite rods are suitable for fixation of cancellous bone osteotomies in rats as long as the operative technique is correct. The present article is the first report on the application of SR-P(L/DL)LA/bioactive glass composite rods for fixation of cancellous bone osteotomies.

Fixation of distal femoral osteotomies with self-reinforced poly(desamino tyrosyl–tyrosine ethyl ester carbonate) rods: an experimental study on rats

AbstractSelf-reinforced poly(desamino tyrosyl–tyrosine ethyl ester carbonate) poly(DTE carbonate) rods (diameter, 2 mm; length, 26 mm) were implanted into the dorsal subcutaneous tissue of 16 rats. Osteotomies of the distal femur were fixed with these rods (2mm by 15mm) in 64 other rats. The follow-up times varied from 1 week to 1 year. After sacrifice, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of the osteotomized and intact control femurs were performed. At 36 weeks, the bending strength of the rods was nearly at the same level as the initial value, and the shear strength was decreased to about one quarter of the initial value. One of the 64 evaluated osteotomies showed signs of infection at 24 weeks, and there were five failures of fixation. Fifty-eight osteotomies healed uneventfully. No gross signs of inflammatory or foreign-body reactions were observed. The present investigation showed that the mechanical strength and fixation properties of SR-poly(DTE carbonate) rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on successful application of SR-poly(DTE carbonate) rods for fixation of cancellous bone osteotomies.

Strength retention of drawn self-reinforced polyglycolide rods and fixation properties of the distal femoral osteotomies with these rods. An experimental study on rats.

Drawn self-reinforced polyglycolide (SR-PGA) rods, Ø 2 mm and 26 mm long, were implanted in the dorsal subcutaneus tissue of 16 rats. Osteotomies of the distal femur were fixed with SR-PGA rods (2 mm by 15 mm) in another 38 rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were also performed. At three weeks the flexural strength of the rods was 50% of the initial value, and the flexural modulus was 46% of the initial value. Five osteotomy specimens had to be excluded due to dislocation or non-union. One of the 33 evaluated osteotomy specimens showed signs of postoperative infection. Thirty-two osteotomies healed uneventfully. No gross signs of inflammatory or foreign-body reaction were observed. The amount of osteoid surface and active osteoid formation surface reached their highest value in the histomorphometrical analysis at 24 weeks. The present investigation demonstrated that the mechanical strength and fixation properties of the drawn SR-PGA rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on the successful application of drawn SR-PGA rods for fixation of cancellous bone osteotomies.

Strength retention of self-reinforced drawn poly-L/DL-lactide 70/30 (SR-PLA70) rods and fixation properties of distal femoral osteotomies with these rods. An experimental study on rats

Self-reinforced polylevo-dextro-lactic acid(SR-PLA)70 composite rods,(2 mm×26 mm) were implanted in the dorsal subcutaneus tissue of sixteen rats. Osteotomies of the distal femur were fixed with SR-PLA70 composite rods (2 mm × 15 mm) in 39 rats. The follow-up times varied from 1 week to 1 year. After sacrifice three-point bending and shear tests were performed for subcutaneously placed rods, and radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were performed. At 52 weeks the shear strength and flexural modulus of the rods were 41% of the initial value, and the flexural strength was 43% of the initial value. In the osteotomies seven specimens had to be excluded due to postoperative infection or dislocation of the fragment. Six of the thirty-two evaluated osteotomies showed signs of postoperative infection. Twenty-six osteotomies healed uneventfully. No signs of inflammatory or foreign-body reaction were observed. The present investigation demonstrated that the mechanical strength and fixation properties of the SR-PLA70 rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on successful application of SR-PLA70 rods for fixation of cancellous bone osteotomies studied.

Intraosseous plating with absorbable self-reinforced poly-L-lactide plates in the fixation of distal femoral osteotomies on rabbits.

Osteotomies of distal femur were fixed by intraosseous self-reinforced poly-L-lactic acid (SR-PLLA) plates in 29 adult rabbits. The follow-up times were from 3 to 24 weeks. After sacrifice, radiological, histological, microradiographic, and oxytetracycline fluorescence studies were performed. Although radiographically no redisplacements were found, in 12 weeks two fixations were broken and a fibrotic nonunion was observed in one case. At 24 weeks full bone consolidation was seen in all except one osteotomy. No foreign-body reactions were observed. The present article is the first report on successful application of absorbable plates for intraosseous fixation of weight-bearing bone osteotomies. The present investigation demonstrated that the SR-PLLA plates were suitable for the fixation of cancellous bone osteotomies in rabbits.