The impact of upright radiographs of midshaft clavicle fractures on treatment recommendations.

Clavicle fractures' treatment recommendations are based on displacement. The goal of this paper is to determine upright clavicle radiographs at initial presentation changes timing and method of treatment. Retrospective study in a level 1 trauma center. 356 patients with clavicle fractures were reviewed. Patients with only supine radiographs (Group 1, 285 patients) were compared to patients with supine and upright radiographs (Group 2, 71 patients). Higher proportion of fractures in the upright vs supine radiographs were displaced 100% or more of the clavicle width, (52.1% vs. 33.5%, p =0.004). Treatment assignment changed from nonoperative to operative treatment more commonly in the Group 2 compared to Group 1 (43.7% vs 21.9%, p =0.019). The most common reason for surgery in Group 1 was presence of continued pain or failure to develop radiographic evidence of callus on serial radiographs (17, 53.1%) as compared to Group 2 (2, 14.2%, p =0.014). In Group 2 the most common cause for treatment change was displacement (12, 85.7%) as compared to Group 1 (15, 46.9%, p =0.014). Patients with upright x-rays are more likely to have a change in treatment because of displacement while patients that had supine x-rays have more delayed/nonunion.

AB5075, a Highly Virulent Isolate of Acinetobacter baumannii, as a Model Strain for the Evaluation of Pathogenesis and Antimicrobial Treatments.

UNLABELLED: Acinetobacter baumannii is recognized as an emerging bacterial pathogen because of traits such as prolonged survival in a desiccated state, effective nosocomial transmission, and an inherent ability to acquire antibiotic resistance genes. A pressing need in the field of A. baumannii research is a suitable model strain that is representative of current clinical isolates, is highly virulent in established animal models, and can be genetically manipulated. To identify a suitable strain, a genetically diverse set of recent U.S. military clinical isolates was assessed. Pulsed-field gel electrophoresis and multiplex PCR determined the genetic diversity of 33 A. baumannii isolates. Subsequently, five representative isolates were tested in murine pulmonary and Galleria mellonella models of infection. Infections with one strain, AB5075, were considerably more severe in both animal models than those with other isolates, as there was a significant decrease in survival rates. AB5075 also caused osteomyelitis in a rat open fracture model, while another isolate did not. Additionally, a Tn5 transposon library was successfully generated in AB5075, and the insertion of exogenous genes into the AB5075 chromosome via Tn7 was completed, suggesting that this isolate may be genetically amenable for research purposes. Finally, proof-of-concept experiments with the antibiotic rifampin showed that this strain can be used in animal models to assess therapies under numerous parameters, including survival rates and lung bacterial burden. We propose that AB5075 can serve as a model strain for A. baumannii pathogenesis due to its relatively recent isolation, multidrug resistance, reproducible virulence in animal models, and genetic tractability. IMPORTANCE: The incidence of A. baumannii infections has increased over the last decade, and unfortunately, so has antibiotic resistance in this bacterial species. A. baumannii is now responsible for more than 10% of all hospital-acquired infections in the United States and has a >50% mortality rate in patients with sepsis and pneumonia. Most research on the pathogenicity of A. baumannii focused on isolates that are not truly representative of current multidrug-resistant strains isolated from patients. After screening of a panel of isolates in different in vitro and in vivo assays, the strain AB5075 was selected as more suitable for research because of its antibiotic resistance profile and increased virulence in animal models. Moreover, AB5075 is susceptible to tetracycline and hygromycin, which makes it amenable to genetic manipulation. Taken together, these traits make AB5075 a good candidate for use in studying virulence and pathogenicity of this species and testing novel antimicrobials.

Incisional negative pressure wound therapy after high-risk lower extremity fractures.

OBJECTIVES: To investigate negative pressure wound therapy (NPWT) to prevent wound dehiscence and infection after high-risk lower extremity trauma. DESIGN: Prospective randomized multicenter clinical trial. SETTING: Four Level I trauma centers. PATIENTS/PARTICIPANTS: Blunt trauma patients with one of three high-risk fracture types (tibial plateau, pilon, calcaneus) requiring surgical stabilization. INTERVENTION: Incisional NPWT (Group B) was applied to the closed surgical incisions of patients randomized to the study arm of this trial, whereas standard postoperative dressings (Group A) were applied to the control patients. MAIN OUTCOME MEASURES: Acute and chronic wound dehiscence and infection. RESULTS: Two hundred forty-nine patients with 263 fractures have enrolled in this study with 122 randomized to Group A (controls) and 141 to Group B (NPWT). There was no difference between the groups in the distribution of calcaneus (39%), pilon (17%), or tibial plateau (44%) fractures. There were a total of 23 infections in Group A and 14 in Group B, which represented a significant difference in favor of NPWT (P = 0.049). The relative risk of developing an infection was 1.9 times higher in control patients than in patients treated with NPWT (95% confidence interval, 1.03-3.55). CONCLUSIONS: There have been no studies evaluating incisional NPWT as a prophylactic treatment to prevent infection and wound dehiscence of high-risk surgical incisions. Our data demonstrate that there is a decreased incidence of wound dehiscence and total infections after high-risk fractures when patients have NPWT applied to their surgical incisions after closure. There is also a strong trend for decreases in acute infections after NPWT. Based on our data in this multicenter prospective randomized clinical trial, NPWT should be considered for high-risk wounds after severe skeletal trauma.

The use of a biodegradable, load-bearing scaffold as a carrier for antibiotics in an infected open fracture model.

OBJECTIVES: Open fractures with bone loss are common, disabling injuries. Biodegradable, load-bearing scaffolds able to carry high concentrations of local antibiotics are an emerging technology to address these injuries. This study investigates the use of such scaffolds with gentamicin (along with bone morphogenetic protein) in an infected rat open fracture model to decrease osteomyelitis and promote fracture healing. METHODS: A contaminated open fracture was created in 32 Brown Norway rats. A comminuted femoral fracture was created, followed by crushing, and the 5-mm bone defect was inoculated with Staphylococcus aureus (10 colony-forming units/mL) and Escherichia coli (10 colony-forming units/mL). The scaffold was stabilized in the defect with an intramedullary Kirschner wire. Gentamicin was loaded onto the scaffolds at two doses, either 10 mg (n = 12) or 20 mg (n = 10). Controls (n = 10) received no antibiotics. All three groups had 10 microg bone morphogenetic protein loaded on the scaffold. Serial radiographs were obtained. Microbiologic analysis, microcomputed tomography, and histology were performed. RESULTS: There was a statistically significant difference in the radiographic evidence of osteomyelitis (P = 0.004) and callus formation (P = 0.021) between the treated and control groups. Bone culture analysis results were not significant for S. aureus (P = 0.29) or E. coli (P = 0.25). There was no difference in the mean scaffold volume or density of the three treatment groups. CONCLUSIONS: Our results suggest that gentamicin applied to a biodegradable scaffold is effective at decreasing radiographically defined osteomyelitis in an infected open fracture.

Quantitative analysis of growth factors from a second filter using the Reamer-Irrigator-Aspirator system: description of a novel technique.

Use of the Reamer-Irrigator-Aspirator (RIA) as a source of autogenous bone graft in the treatment of nonunions is increasing. We report on our novel technique of using a second filter containing beta-tricalcium phosphate (TCP) as a graft extender while using the RIA system. We also quantify growth factor concentrations in the collections from the TCP filter. A second filter attached in series with the standard RIA filtration system yields TCP with substantial concentrations of bioactive proteins that are equal to those seen in the bone graft that is harvested in the first filter.

Subtrochanteric femur fracture after core decompression and placement of a tantalum strut for osteonecrosis of the femoral head.

Multiple treatment options have been described to treat osteonecrosis of the femoral head, all with the goal of slowing or reversing the disease process and preventing the need for arthroplasty in a young patient population. Core decompression of the femoral head to allow revascularization is a commonly used technique that can now be supplemented by placement of the Osteonecrosis Intervention Implant (Zimmer, Warsaw, Ind). It consists of a tantalum strut that acts as a buttress for the subchondral bone of the femoral head. In this case, our patient underwent this procedure with subsequent subtrochanteric fracture. The factors leading to this iatrogenic injury are location of implant insertion, patient selection, and premature ambulation.

Segmental bone regeneration using a load-bearing biodegradable carrier of bone morphogenetic protein-2.

Segmental defect regeneration has been a clinical challenge. Current tissue-engineering approach using porous biodegradable scaffolds to delivery osteogenic cells and growth factors demonstrated success in facilitating bone regeneration in these cases. However, due to the lack of mechanical property, the porous scaffolds were evaluated in non-load bearing area or were stabilized with stress-shielding devices (bone plate or external fixation). In this paper, we tested a scaffold that does not require a bone plate because it has sufficient biomechanical strength. The tube-shaped scaffolds were manufactured from poly(propylene) fumarate/tricalcium phosphate (PPF/TCP) composites. Dicalcium phosphate dehydrate (DCPD) were used as bone morphogenetic protein-2 (BMP-2) carrier. Twenty-two scaffolds were implanted in 5mm segmental defects in rat femurs stabilized with K-wire for 6 and 15 weeks with and without 10 microg of rhBMP-2. Bridging of the segmental defect was evaluated first radiographically and was confirmed by histology and micro-computer tomography (microCT) imaging. The scaffolds in the BMP group maintained the bone length throughout the duration of the study and allow for bridging. The scaffolds in the control group failed to induce bridging and collapsed at 15 weeks. Peripheral computed tomography (pQCT) showed that BMP-2 does not increase the bone mineral density in the callus. Finally, the scaffold in BMP group was found to restore the mechanical property of the rat femur after 15 weeks. Our results demonstrated that the load-bearing BMP-2 scaffold can maintain bone length and allow successfully regeneration in segmental defects.

Ultrasound produced by a conventional therapeutic ultrasound unit accelerates fracture repair.

BACKGROUND AND PURPOSE: A recent novel application of ultrasound therapy is the treatment of bone fractures. The aim of this study was to investigate the effect on fracture repair of ultrasound produced by a conventional therapeutic ultrasound unit as used by physical therapists. SUBJECTS AND METHODS: Bilateral midshaft femur fractures were created in 30 adult male Long-Evans rats. Ultrasound therapy was commenced on the first day after fracture and introduced 5 days a week for 20 minutes a day. Each animal was treated unilaterally with active ultrasound and contralaterally with inactive ultrasound. Active ultrasound involved a 2-millisecond burst of 1.0-MHz sine waves repeating at 100 Hz. The spatially averaged, temporally averaged intensity was set at 0.1 W/cm2. Animals were killed at 25 and 40 days after fracture induction, and the fractures were assessed for bone mass and strength. RESULTS: There were no differences between fractures treated with active ultrasound and fractures treated with inactive ultrasound at 25 days. However, at 40 days, active ultrasound-treated fractures had 16.9% greater bone mineral content at the fracture site than inactive ultrasound-treated fractures. This change resulted in a 25.8% increase in bone size, as opposed to an increase in bone density, and contributed to active ultrasound-treated fractures having 81.3% greater mechanical strength than inactive ultrasound-treated fractures. DISCUSSION AND CONCLUSION: These data indicate that ultrasound produced by a conventional therapeutic ultrasound unit as traditionally used by physical therapists may be used to facilitate fracture repair. However, careful interpretation of this controlled laboratory study is warranted until its findings are confirmed by clinical trials.

Preliminary evaluation of a load-bearing BMP-2 carrier for segmental defect regeneration.

Large segmental defects in bones can result from tumor removal, massive trauma, congenital malformation, or non-union fractures. Such defects often are difficult to manage and require multiple-phase surgery to achieve adequate union and function. In this study, we propose a novel design of bone morphogenetic protein 2 (BMP-2) carrier for tissue engineering of segmental defect regeneration. The tube-shaped BMP-2 carrier was fabrication from a poly(propylene fumarate)/tricalcium phosphate (PPF/TCP) composite via casting technique developed in our laboratory. An in vitro evaluation showed that the compressive strength of the carrier decreased about 48% in 12 weeks while maintained a pH in the 6.8-7.4 range. In vivo study was conducted by implanting carriers loaded with 10 microg of BMP-2 in 5 mm rat femur gap model for 15 weeks. X-ray evidence of bridging was first found in the BMP group at 3 weeks. Bridging in all animals (N = 4) in the BMP group was found at 9 weeks. No x-ray evidence of bridging was found in the No BMP group (N = 3). pQCT analysis indicated that the bone mineral density of the callus in the BMP group has reached the level of native femur at 15 weeks after implantation, while the callus in the No BMP group has a bone mineral density at a lower level of 84% to the native femur. Histology analysis shows that a normal fatty bone marrow was restored and mineralized callus formed and bridged the segmental defect.

Effect of low molecular weight heparin on fracture healing in a stabilized rat femur fracture model.

The purpose of this study was to evaluate the effect of low molecular weight heparin (LMWH) on fracture healing in a standard stabilized rat femur fracture model. A closed, mid-diaphyseal transverse fracture was created in the right femur of Long-Evans rats after insertion of a 0.8-mm K-wire into the medullary canal. Animals were randomized to receive either LMWH (70 units/kg dalteparin) or an injection of normal saline daily for 2 weeks. Animals were sacrificed at 2, 3, and 6 weeks. Fracture healing was assessed by radiographs, histology, and mechanical testing. There were no significant differences between the control and LMWH groups in the percentage of animals with radiographic bridging callus at each time point. Histologic appearance of fracture healing was similar between the control and LMWH groups. There were no significant differences in the normalized mechanical properties of the control and LMWH groups at 2 and 3 weeks. At 6 weeks, the percent torque of the LMWH group was significantly greater than the control group ( p = 0.0072), however, there was no significant difference in the stiffness and energy absorption. Dalteparin, at the dosage used in this study, did not impair fracture healing in this standard stabilized rat femur fracture model.

Preliminary stabilization of the less invasive stabilization system.

We describe the use of a universal T-handle chuck to provide preliminary stabilization of the Less Invasive Stabilization System supracondylar femur implant and aiming device. This technique is helpful to maintain the position of the plate against the bone during intraoperative radiographs and initial screw insertion. Use of this simple technique may help avoid the problems that occur when the plate is positioned too far away from the lateral femoral cortex.

Snowmobile trauma: 10 years' experience at Manitoba's tertiary trauma centre.

INTRODUCTION: According to the literature, the increased recreational use of the snowmobile has resulted in an increasing number of musculoskeletal injuries. We wished to examine whether previously described risk factors continue to be associated with snowmobile trauma and to identify previously unrecognized risks and specific patterns of injury. METHODS: We carried out a chart review of all snowmobile-related injuries over a 10-year period at the Health Sciences Centre in Winnipeg, the only level 1 trauma centre serving the Province of Manitoba, with particular attention to the risk factors of suboptimal lighting, excessive speed and alcohol consumption. RESULTS: We identified 480 injuries in 294 patients, and 81 (27.6%) of these patients died. Collisions accounted for 72% of the injury mechanisms. Of the injuries sustained, 31% occurred on roads. Excessive speed was a risk factor in 54% of patients, suboptimal lighting in 86% and a blood alcohol level greater than 0.08 in 70%. Musculoskeletal injuries accounted for 57% of those recorded. There were also brachial plexus injuries (3%) and knee dislocations (2%). To our knowledge, this is the largest study detailing injury associated with recreational use of snowmobiles in Canada. CONCLUSIONS: Because snowmobile trauma is caused principally by human errors, it is potentially preventable. Efforts aimed at prevention must focus on the driver, who controls the common risk factors. The danger of snowmobiling while intoxicated must be emphasized. Trail-side monitoring is likely to be ineffective, as the majority of accidents do not occur on designated snowmobile trails.