Union of a Chronically Infected Internally Stabilized Segmental Defect in the Rat Femur After Debridement and Application of rhBMP-2 and Systemic Antibiotic

Chen, Xinqian; Schmidt, Andrew H.; Mahjouri, Sormeh; Polly, David W.; Lew, William D.

doi:10.1097/bot.0b013e31815a7e91

Cited by 32 publications

(52 citation statements)

References 19 publications

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“…These controls may have shown that no bone formation occurs in the absence of MDR AB. Bone formation has not been observed in this model of infection without some form of osteogenic treatment [3][4][5]. One explanation could be that the newly formed bone may be the result of the presence of the absorbable collagen sponge used to retain the bacteria in the defect in the short term.…”

Section: Discussionmentioning

confidence: 82%

“…Recovered P. aeruginosa at 2 and 3 weeks were larger than initial inocula. Moreover, 10 6 CFUs of P. aeruginosa combined with 10 3 and 10 4 CFUs of SA resulted in dyspnea and death in several animals. In addition to the surprising reduction in bacterial counts with MDR AB, no bony lysis was radiographically evident at Weeks 2, 4, and 8 using 10 8 CFU of tracheal and bone isolates of MDR AB ( Table 2).…”

Section: Resultsmentioning

confidence: 98%

“…One explanation could be that the newly formed bone may be the result of the presence of the absorbable collagen sponge used to retain the bacteria in the defect in the short term. However, the presence of the collagen sponge in an uninfected defect is not osteogenic: we chose this defect model because it is critical, meaning no bone forms unless an osteogenic treatment is applied [3][4][5]. Seventh, the virulence of SA was such that the polymicrobial experiments were not performed past 3 weeks.…”

Section: Discussionmentioning

confidence: 99%

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Acinetobacter baumannii is not Associated with Osteomyelitis in a Rat Model: A Pilot Study

Collinet-Adler¹,

Castro²,

Ledonio³

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background Multidrug resistant Acinetobacter baumannii (MDR AB) with and without Staphylococcus aureus (SA) is a commonly isolated organism in infected segmental bone defects in combat-related trauma in Iraq and Afghanistan. Although MDR AB in visceral infections is a therapeutic challenge, control of infection appears more common for combat-related osteomyelitis.Questions/purposes Using a rat model, we explored the virulence of MDR AB in segmental bone defects alone and in combination with SA. Methods Segmental defects in 60 rat femurs were created, stabilized, and inoculated with MDR AB alone and 60 with MDR AB and SA. We performed qualitative and quantitative bacteriology and radiographic assessments at 2, 4, and 8 weeks for MDR AB and at 1, 2, and 3 weeks for MDR AB and SA. Results Quantitative bacteriology revealed a 3-to 5-log decrease in MDR AB from the initial inoculum. After polymicrobial inoculation, only 10 of 60 animals had positive cultures for MDR AB, whereas 59 of 60 animals had positive cultures for SA. Recovered SA were 2 to 5 log greater than the initial inoculum, while there again was a 3-to 5-log decrease in MDR AB. MDR AB alone did not cause bony lysis, but there was radiographic evidence of new bone formation in 67% of the segmental defects. Osteolysis was noted with MDR AB and SA. Conclusions MDR AB did not appear to cause or contribute to clinically apparent osteomyelitis in this pilot study. Clinical Relevance Resolution of infections in combatrelated segmental bone defects inoculated with MDR AB may be attributable to low virulence.

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Section: Discussionmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Acinetobacter baumannii is not Associated with Osteomyelitis in a Rat Model: A Pilot Study

Collinet-Adler¹,

Castro²,

Ledonio³

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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show abstract

“…A power analysis based on a previous study was used to determine the number of animals [2]. Assuming a power level of 0.8 and p value of 0.05, six animals would be required to determine a 60% difference between infection and noninfection groups in terms of mechanical testing.…”

Section: Discussionmentioning

confidence: 99%

“…In previous studies of infected fracture models, callus tissue was observed in the infected fracture area under the supply of antibiotics [2,3,24]. The difference from these studies is that no antibiotics were used and no segmental defects were created.…”

Section: Discussionmentioning

confidence: 99%

Can Normal Fracture Healing Be Achieved When the Implant Is Retained on the Basis of Infection? An Experimental Animal Model

Bilgili

Balcı

Karaytuğ

et al. 2015

Clin Orthop Relat Res

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Background Infection after open fractures is a common complication. Treatment options for infections developed after intramedullary nailing surgery remain a topic of controversy. We therefore used a rat fracture model to evaluate the effects of infection on osseous union when the implant was maintained.Questions/purposes In a rat model, (1) does infection alter callus strength; (2) does infection alter the radiographic appearance of callus; and (3) does infection alter the histological properties of callus? Methods An open femoral fracture was created and fixed with an intramedullary Kirschner wire in 72 adult male Sprague-Dawley rats, which were divided into two study groups. In the infection group, the fracture site was contaminated with Staphylococcus aureus (36 animals), whereas in the control group, there was no bacterial contamination (36 animals). No antibiotics were used either for prophylaxis or for treatment. We performed biomechanical (maximum torque causing failure and stiffness), radiographic (Lane and Sandhu scoring for callus formation), and histologic (scoring for callus maturity) assessments at 3 and 6 weeks. The number of bacteria colonies on the femur, wire, and soft tissue inside knee were compared to validate that we successfully created an infection model. The number of bacteria colonies in the soft tissue inside the knee was higher in the infection group after 6 weeks than after the third week, demonstrating the presence of locally aggressive infection. Results Infection decreased callus strength at 6 weeks. Torque to failure (299.07 ± 65.53 Nmm versus 107.20 ± 88.81, mean difference with 95% confidence interval, 192 [43-340]; p = 0.007) and stiffness at 6 weeks (11.28 ± 2.67 Nmm versus 2.03 ± 1.68, mean difference with 95% confidence interval, 9 [3-16]; p = 0.004) both were greater in the control group than in the group with infection.

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Long‐bone critical‐size defects treated with tissue‐engineered polycaprolactone‐co‐lactide scaffolds: A pilot study on rats

Rentsch

Rentsch²,

Breier

et al. 2010

J Biomedical Materials Res

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The aim of this study was to evaluate the osteogenic potential of embroidered, tissue-engineered polycaprolactone-co-lactide (trade name: PCL) scaffolds for the reconstruction of large bone defects. Ten piled-up PCL scaffolds were implanted in femura with a critical size defect of immunodeficient nude rats for 12 weeks [n = 4, group 1: noncoated, group 2: collagen I (coll I), group 3: collagen I/chondroitin sulfate (coll I/CS), and group 4: collagen I/chondroitin sulfate/human mesenchymal stem cells (coll I/CS/hMSC)]. X-ray examination, computer tomography, and histological analyses of the explanted scaffold pads were performed. The quantification of the bone volume ratio showed a significantly higher rate of new bone formation at coll I/CS-coated scaffolds compared with the other groups. Histological investigations revealed that the defect reconstruction started from the peripheral bone ends and incorporated into the scaffold material. Additionally seeded hMSC on coll I/CS-coated scaffolds showed a higher matrix deposition inside the implant but no higher bone formation was observed. These data imply that the coll I/CS-coated PCL scaffolds have the highest potential for treating critical size defects. The scaffolds, being variable in size and structure, can be adapted to any bone defect.

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Union of a Chronically Infected Internally Stabilized Segmental Defect in the Rat Femur After Debridement and Application of rhBMP-2 and Systemic Antibiotic

Cited by 32 publications

References 19 publications

Acinetobacter baumannii is not Associated with Osteomyelitis in a Rat Model: A Pilot Study

Acinetobacter baumannii is not Associated with Osteomyelitis in a Rat Model: A Pilot Study

Can Normal Fracture Healing Be Achieved When the Implant Is Retained on the Basis of Infection? An Experimental Animal Model

Long‐bone critical‐size defects treated with tissue‐engineered polycaprolactone‐co‐lactide scaffolds: A pilot study on rats

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