Negative pressure wound therapy in grade IIIB tibial fractures: fewer infections and fewer flap procedures?

BACKGROUND: Grade IIIB open tibia fractures are devastating injuries. Some clinicians advocate wound closure or stable muscle flap coverage within 72 hours to limit complications such as infection. Negative pressure wound therapy was approved by the FDA in 1997 and has become an adjunct for many surgeons in treating these fractures. Opinions vary regarding the extent to which negative pressure wound therapy contributes to limb salvage. Evidence-based practice guidelines are limited for use of negative pressure wound therapy in Grade IIIB tibia fractures. This systematic literature review of negative pressure wound therapy in Grade IIIB tibia fractures may substantiate current use and guide future studies. QUESTIONS/PURPOSES: We sought to answer the following: (1) Does the use of negative pressure would therapy compared with gauze dressings lead to fewer infections? (2) Does it allow flap procedures to be performed safely beyond 72 hours without increased infection rates? (3) Is it associated with fewer local or free flap procedures? METHODS: We conducted a systematic review of six large databases (through September 1, 2013) for studies reporting use of negative pressure wound therapy in Grade IIIB open tibia fractures, including information regarding infection rates and soft tissue reconstruction. The systematic review identified one randomized controlled trial and 12 retrospective studies: four studies compared infection rates between negative pressure wound therapy and gauze dressings, 10 addressed infection rates with extended use, and six reported on flap coverage rates in relation to negative pressure wound therapy use beyond 72 hours. None of the 13 studies was eliminated owing to lack of study quality. RESULTS: Negative pressure wound therapy showed a decrease in infection rates over rates for gauze dressings in two of four studies (5.4% [two of 35] versus 28% [seven of 25], and 8.4% [14 of 166] versus 20.6% [13 of 63]), an equivalent infection rate in one study (15% [eight of 53] versus 14% [five of 16]), and an increased infection rate in the fourth study (29.5% [23 of 78] versus 8% [two of 25]). In terms of the second question regarding infection rates with negative pressure wound therapy beyond 72 hours, eight of 10 studies concluded there was no increase in infection rates, whereas two of 10 reported an increase in infection rates associated with negative pressure wound therapy use beyond 72 hours. Infection rates varied from 0% to 57% in these 10 studies. Five studies reported low infection rates of 0% to 7% and five reported rates of 27% to 57%. The third question (addressed by six studies) regarded the potential decreased use of a soft tissue flap in patients treated with extended negative pressure wound therapy. Flap rates were reduced by 13% to 60% respectively compared with those of historical controls. Grade IIIB tibia fractures by definition required soft tissue procedures. The patients in these six studies had Grade IIIB tibia fractures after the first débridement. However, after extended negative pressure wound therapy, fewer patients required flaps than grading at the first débridement would have predicted. CONCLUSIONS: There is an increasing body of data supporting negative pressure wound therapy as an adjunctive modality at all stages of treatment for Grade IIIB tibia fractures. There is an association between decreased infection rates with negative pressure wound therapy compared with gauze dressings. There is evidence to support negative pressure wound therapy beyond 72 hours without increased infection rates and to support a reduction in flap rates with negative pressure wound therapy. However, negative pressure wound therapy use for Grade IIIB tibia fractures requires extensive additional study. LEVEL OF EVIDENCE: Level III, therapeutic study.

Can freshwater plants and algae act as an effective feed supplement to reduce methane emissions from ruminant livestock?

Methane production by livestock is a substantial component of greenhouse gas emissions worldwide. The marine red algae, Asparagopsis taxiformis, has been identified as a possible supplement in livestock feeds due to its potent inhibition of methane production but currently is unable to be produced at scale. Finding additional taxa that inhibit methane production is therefore desirable. Here we provide foundational evidence of methanogenesis-inhibiting properties in Australian freshwater plants and algae, reviewing candidate species and testing species' chemical composition and efficacy in vitro. Candidate plant species and naturally-occurring algal mixes were collected and assessed for ability to reduce methane in batch testing and characterised for biochemical composition, lipids and fatty acids, minerals and DNA. We identified three algal mixes and one plant (Montia australasica) with potential to reduce methane yield in in vitro batch assay trials. All three algal mixes contained Spirogyra, although additional testing would be needed to confirm this alga was responsible for the observed activity. For the two samples that underwent multiple dose testing, Algal mix 1 (predominantly Spirogyra maxima) and M. australasica, there seems to be an optimum dose but sources, harvesting and storage conditions potentially determine their methanogenesis-inhibiting activity. Based on their compositions, fatty acids are likely to be acting to reduce methane in Algal mix 1 while M. australasica likely contains substantial amounts of the flavonoids apigenin and kaempferol, which are associated with methane reduction. Based on their mineral composition, the samples tested would be safe for livestock consumption at an inclusion rate of 20%. Thus, we identified multiple Australian species that have potential to be used as a feed supplement to reduce methane yield in livestock which may be suitable for individual farmers to grow and feed, reducing complexities of supply associated with marine alternatives and suggesting avenues for investigation for similar species elsewhere.

Microvascular effects of subatmospheric pressure in striated muscle.

OBJECTIVE: Topical application of subatmospheric pressure (TASAP) promotes faster wound healing, but tissue effects are not entirely understood. This study investigated microvascular effects of TASAP in striated muscle with the hypothesis being that TASAP elicits arteriolar vasodilation and decreases interstitial accumulation of protein. METHODS: Rat cremasteric microcirculation was directly examined in two experiments utilizing a novel technique. First, TASAP was applied to the cremaster in three experimental groups and a non-TASAP control group. Arteriolar diameters were directly measured before and after TASAP. In experiment two, intravascular fluorescein isothiocyanate (FITC)-labeled albumin and topical leukotriene B4 (LTB4) were delivered to the cremaster. Microvascular permeability was assessed by measuring the accumulation/disappearance of FITC-albumin in the interstitial tissue. RESULTS: TASAP produced significant arteriolar vasodilation compared with control values. The mean maximum percent increase in diameter with TASAP was 8.70% at -2 kPa (p < 0.05), 7.16% at -4 kPa (p < 0.05), and 10.43% at -6 kPa (p < 0.01). TASAP decreased interstitial FITC-albumin by 26.3% (p < 0.008) following LTB4; the control group showed a steady increase in interstitial FITC-albumin. CONCLUSIONS: These results support the hypothesis that TASAP elicits significant arteriolar vasodilation with a subsequent increase in blood flow as well as a decrease in interstitial protein accumulation.

Investigation on removal of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) using water treatment sludge and biochar.

This work assessed the adsorption performance of three common PFAS compounds (PFOA, PFOS and PFHxS) on two water treatment sludges (WTS) and two biochars (commercial biomass biochar and semi-pilot scale biosolids biochar). Of the two WTS samples included in this study, one was sourced from poly-aluminium chloride (PAC) and the other from alum (Al2(SO4)3). The results of experiments using a single PFAS for adsorption reinforced established trends in affinity - the shorter-chained PFHxS was less adsorbed than PFOS, and the sulphates (PFOS) were more readily adsorbed than the acid (PFOA). Interestingly, PAC WTS, showed an excellent adsorption affinity for the shorter chained PFHxS (58.8%), than the alum WTS and biosolids biochar at 22.6% and 41.74%, respectively. The results also showed that the alum WTS was less effective at adsorption than the PAC WTS despite having a larger surface area. Taken together, the results suggest that the hydrophobicity of the sorbent and the chemistry of the coagulant were critical factors for understanding PFAS adsorption on WTS, while other factors, such as the concentration of aluminium and iron in the WTS could not explain the trends seen. For the biochar samples, the surface area and hydrophobicity are believed to be the main drivers in the different performances. Adsorption from the solution containing multiple PFAS was also investigated with PAC WTS and biosolids biochar, demonstrating comparable performance on overall adsorption. However, the PAC WTS performed better with the short-chain PFHxS than the biosolids biochar. While both PAC WTS and biosolids biochar are promising candidates for adsorption, the study highlights the need to explore further the mechanisms behind PFAS adsorption, which could be a highly variable source to understand better the potential for WTS to be utilized as a PFAS adsorbent.

An O-Specific Polysaccharide/Tetanus Toxoid Conjugate Vaccine Induces Protection in Guinea Pigs against Virulent Challenge with Coxiella burnetii.

Q fever is caused by the bacterium Coxiella burnetii and is spread to humans from infected animals especially goats, sheep and cattle, predominantly when giving birth. There is an effective human vaccine (Q-VAX) against Q fever, and although Q fever is a worldwide problem, the vaccine is only used in Australia due to difficulties associated with its use and the risk of adverse reactions. The desire to protect humans, particularly farmers and abattoir workers, from Q fever prompted the development of a new safe and effective human vaccine without all the difficulties associated with the current vaccine. Candidate vaccines were prepared using purified O-specific polysaccharide (OSP) extracted from the lipopolysaccharide of virulent (phase 1) C. burnetii, strain Nine Mile, which was then conjugated to a tetanus toxoid (TT) carrier protein. Two vaccines were prepared using OSP from C. burnetii grown in embryonated eggs (vaccine A) and axenic media (vaccine B). Vaccines with or without alum adjuvant were used to vaccinate guinea pigs, which were later challenged by intranasal inoculation with virulent C. burnetii. Both vaccines protected guinea pigs from fever and loss of weight post challenge. Post-mortem samples of the spleen, liver and kidney of vaccinated guinea pigs contained substantially less C. burnetii DNA as measured by PCR than those of the unvaccinated control animals. This study demonstrated that a C. burnetii OSP-TT conjugate vaccine is capable of inducing protection against virulent C. burnetii in guinea pigs. Additionally, OSP derived from C. burnetii grown in axenic media compared to OSP from embryonated eggs is equivalent in terms of providing a protective immune response.

Diagnosis and management of chronic infection.

High-energy penetrating extremity injuries are often associated with severe open fractures that have varying degrees of soft-tissue contamination and tenuous soft-tissue coverage. The result is a relatively high prevalence of chronic osteomyelitis compared with that in civilian trauma patients. Diagnosing chronic osteomyelitis requires a careful history and thorough physical and radiographic examinations. Cross-sectional imaging can help delineate the extent of bony involvement, and scintigraphy can be used as a diagnostic tool and to gauge response to treatment. Clinical staging also directs surgical management. Adequacy of débridement remains the most important clinical predictor of success; thus, adopting an oncologic approach to complete (ie, wide) excision is important. Reconstruction can be safely performed by a variety of methods; however, proper staging and patient selection remain critical to a successful outcome. Although systemic and depot delivery of antibiotics plays a supporting role in the treatment of chronic osteomyelitis, the ideal dosing regimens, and the duration of treatment, remain controversial.

Soft-tissue management after trauma: initial management and wound coverage.

Before proceeding with treatment, it is necessary to recognize that bony injuries are always associated with soft-tissue disruption and damage. A good soft-tissue envelope is essential to fracture healing and overall extremity function. Injury management begins by recognizing and classifying the injury. Wound débridement with irrigation fluid at low pressure and the administration of antibiotics are essential aspects of treatment. Wound treatment starts with applying dressing material using negative suction and can be guided by the tenets of an algorithm modeled on the reconstructive ladder.

The mangled limb: salvage versus amputation.

A mangled extremity is defined as a limb with injury to three of four systems in the extremity. The decision to salvage or amputate the injured limb has generated much controversy in the literature, with studies to support advantages of each approach. Various scoring systems have proved unreliable in predicting the need for amputation or salvage; however, a recurring theme in the literature is that the key to limb viability seems to be the severity of the soft-tissue injury. Factors such as associated injuries, patient age, and comorbidities (such as diabetes) also should be considered. Attempted limb salvage should be considered only if a patient is hemodynamically stable enough to tolerate the necessary surgical procedures and blood loss associated with limb salvage. For persistently hemodynamically unstable patients and those in extremis, life comes before limb. Recently, the Lower Extremity Assessment Project study attempted to answer the question of whether amputation or limb salvage achieves a better outcome. The study also evaluated other factors, including return-to-work status, impact of the level of and bilaterality of the amputation, and economic cost. There appears to be no significant difference in return to work, functional outcomes, or the cost of treatment (including the prosthesis) between the two groups. A team approach with different specialties, including orthopaedics, plastic surgery, vascular surgery and trauma general surgery, is recommended for treating patients with a mangled extremity.

The effect of incisional negative pressure therapy on wound complications after acetabular fracture surgery.

The purpose of the study was to determine if the use of incisional negative pressure therapy affected the rate of wound complications after acetabular fracture surgery. Between August 1996 to April 2005, 301 patients were found to have had an operatively treated acetabular fracture. There were 235 patients who had placement of incisional vacuum-assisted closure (VAC) who had three (1.27%) deep wound infections and one (0.426%) wound dehiscence. There were 66 consecutive patients who were available in the 5 years preceding the usage of the incisional VAC who had four (6.06%) deep wound infections and two (3.03%) wound dehiscences. This is less than the published infection rate of 4% for patients undergoing operative treatment of acetabular fractures and less than the authors' rate of 6.15% in the time period before the use of the incisional negative pressure wound therapy (p=.0414). The use of incisional negative pressure wound therapy significantly decreases perioperative wound complications after acetabular fracture surgery.

Relationship between intraoperative femoral head bleeding and development of avascular necrosis after acetabular fracture surgery.

The purpose of this study was to determine whether the presence or absence of bleeding after drilling of the femoral head can be used to predict the development of avascular necrosis (AVN) after operative treatment of acetabular fractures. A computerized medical record search from 1996 to 2005 of all patients with an operatively treated acetabular fracture yielded 146 patients who had an intraoperative assessment of the vascularity of their femoral head and 72 of whom were available for a minimum of 12 months of follow-up. The average time to the development of AVN was 99.6 weeks with a range of 21-290 weeks. Eleven of the patients in the analysis eventually developed AVN. The p value is not significant at. 092. Although the difference between groups is not significant, it does appear that there is a relationship between femoral head bleeding and the development of avascular necrosis.

Evidence of beneficial effect of physical therapy after lower-extremity trauma.

OBJECTIVE: To examine the effect of physical therapy (PT) use on a range of measures of physical impairment in a cohort of patients with lower-extremity trauma. DESIGN: Longitudinal, observational study of patients with severe lower-extremity trauma. Patients were interviewed by a research coordinator and examined by an orthopedic surgeon and a physical therapist during initial admission and at 3, 6, 12, and 24 months postdischarge. SETTING: Eight level I trauma centers. PARTICIPANTS: Patients (N=382) whose legs were salvaged after limb-threatening trauma to the lower limb. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Unmet need for PT was assessed from 2 perspectives: an orthopedic surgeon and a physical therapist independently evaluated each patient and were asked whether the patient would benefit from PT. Patients classified by these health professionals as needing PT services over a given period and who reported receiving no PT at the end of that period were classified as having unmet need as evaluated by the orthopedic surgeon or physical therapist for that follow-up period. Multiple variable regression techniques were used to compare improvement in 5 measures of physical impairment and functional limitation between the met and unmet need groups over the periods of 3 to 6, 6 to 12, and 12 to 24 months: percentage of impairment in knee and ankle range of motion (ROM), reciprocal stair climbing pattern, gait deviations when walking, self-selected walking speed greater than 1.2 m/s (4 ft/s), and the mobility subscores of the FIM instrument. RESULTS: Patients with unmet need for PT as assessed by a physical therapist were statistically significantly less likely to improve in all 5 of the selected domains of physical impairment and functional limitation than patients whose PT need was met. These results remained constant after adjustment for patient sociodemographic, personality, and social resources, as well as injury and treatment characteristics, reported pain intensity, and impairment level at the beginning of the study period. Patients with unmet need for PT as evaluated by an orthopedic surgeon were significantly worse off than patients with met need in only 1 of the 5 selected measures (ROM). CONCLUSIONS: The results are consistent with a beneficial effect of PT after lower-extremity trauma. The results point to a need for improved standards for the prescription of PT services, and highlight the importance of involving a PT professional in the prescribing process.

An analysis of outcomes of reconstruction or amputation after leg-threatening injuries.

BACKGROUND: Limb salvage for severe trauma has replaced amputation as the primary treatment in many trauma centers. However, long-term outcomes after limb reconstruction or amputation have not been fully evaluated. METHODS: We performed a multicenter, prospective, observational study to determine the functional outcomes of 569 patients with severe leg injuries resulting in reconstruction or amputation. The principal outcome measure was the Sickness Impact Profile, a multidimensional measure of self-reported health status (scores range from 0 to 100; scores for the general population average 2 to 3, and scores greater than 10 represent severe disability). Secondary outcomes included limb status and the presence or absence of major complications resulting in rehospitalization. RESULTS: At two years, there was no significant difference in scores for the Sickness Impact Profile between the amputation and reconstruction groups (12.6 vs. 11.8, P=0.53). After adjustment for the characteristics of the patients and their injuries, patients who underwent amputation had functional outcomes that were similar to those of patients who underwent reconstruction. Predictors of a poorer score for the Sickness Impact Profile included rehospitalization for a major complication, a low educational level, nonwhite race, poverty, lack of private health insurance, poor social-support network, low self-efficacy (the patient's confidence in being able to resume life activities), smoking, and involvement in disability-compensation litigation. Patients who underwent reconstruction were more likely to be rehospitalized than those who underwent amputation (47.6 percent vs. 33.9 percent, P=0.002). Similar proportions of patients who underwent amputation and patients who underwent reconstruction had returned to work by two years (53.0 percent and 49.4 percent, respectively). CONCLUSIONS: Patients with limbs at high risk for amputation can be advised that reconstruction typically results in two-year outcomes equivalent to those of amputation.

Analysis of surgeon-controlled variables in the treatment of limb-threatening type-III open tibial diaphyseal fractures.

BACKGROUND: The open tibial diaphyseal fracture remains a treatment challenge. The purpose of the present analysis of the long-term follow-up data on a previously reported cohort of patients was to identify surgeon-controlled variables that affected fracture union, complications, and final outcome in patients who had sustained a severe open tibial shaft fracture. METHODS: A cohort of 156 patients with a limb-threatening open tibial diaphyseal fracture was identified from the Lower Extremity Assessment Project (LEAP) study group. The patients were prospectively followed for two to seven years. In addition to the Sickness Impact Profile, other outcome metrics included the time to fracture union as well as the occurrence of infection and other complications that required rehospitalization. Statistical differences between groups were calculated. RESULTS: Within the parameters of the present study, the timing of débridement, the timing of soft-tissue coverage, and the timing of bone-graft placement had no effect on outcome. Patients in whom the fracture was definitively treated with an external fixator had more surgical procedures, took longer to achieve full weight-bearing status, and had more readmissions to the hospital for the treatment of infection and nonunion than did those in whom the fracture was treated with an intramedullary nail. Patients undergoing external fixation who also had a muscle flap for wound coverage had more physical impairment and a worse functional outcome than did patients who had an amputation. CONCLUSIONS: Surgeons should carefully consider alternative treatment options for patients who have a severe open tibial fracture when limb salvage is perceived to require the combination of external fixation for fracture fixation and a muscle flap for wound coverage.

Health-care costs associated with amputation or reconstruction of a limb-threatening injury.

BACKGROUND: Recent reports have suggested that functional outcomes are similar following either amputation or reconstruction of a severely injured lower extremity. The goal of this study was to compare two-year direct health-care costs and projected lifetime health-care costs associated with these two treatment pathways. METHODS: Two-year health-care costs were estimated for 545 patients with a unilateral limb-threatening lower-extremity injury treated at one of eight level-I trauma centers. Included in the calculation were costs related to (1) the initial hospitalization, (2) all rehospitalizations for acute care related to the limb injury, (3) inpatient rehabilitation, (4) outpatient doctor visits, (5) outpatient physical and occupational therapy, and (6) purchase and maintenance of prosthetic devices. All dollar figures were inflated to constant 2002 dollars with use of the medical service Consumer Price Index. To estimate projected lifetime costs, the number of expected life years was multiplied by an estimate of future annual health-care costs and added to an estimate of future costs associated with the purchase and maintenance of prosthetic devices. RESULTS: When costs associated with rehospitalizations and post-acute care were added to the cost of the initial hospitalization, the two-year costs for reconstruction and amputation were similar. When prosthesis-related costs were added, there was a substantial difference between the two groups ($81,316 for patients treated with reconstruction and $91,106 for patients treated with amputation). The projected lifetime health-care cost for the patients who had undergone amputation was three times higher than that for those treated with reconstruction ($509,275 and $163,282, respectively). CONCLUSIONS: These estimates add support to previous conclusions that efforts to improve the rate of successful reconstructions have merit. Not only is reconstruction a reasonable goal at an experienced level-I trauma center, it results in lower lifetime costs.

The use of negative-pressure wound therapy (NPWT) in the temporary treatment of soft-tissue injuries associated with high-energy open tibial shaft fractures.

OBJECTIVES: To evaluate the utility of negative-pressure wound therapy (NPWT) in the setting of high-energy open tibial shaft fractures. DESIGN, SETTING, AND PATIENTS/PARTICIPANTS: This was a retrospective consecutive series in a level 1 university-based trauma center. Forty-nine consecutive patients presenting to a level 1 trauma center between 1996 and 2004 with 50 grade/type III open tibial shaft fractures were assessed. INTERVENTION: The open wounds associated with each fracture were each treated with NPWT before definitive wound closure or coverage. MAIN OUTCOME MEASUREMENTS: Infection rate, need for amputation after attempted definitive coverage, problems with bony healing requiring surgical intervention, reoperation rate after definitive coverage, and the type of definitive coverage required. RESULTS: The overall infection rate for all grade/type III open fractures was 15 of 50 fractures (30%), with 11 of 50 (22%) requiring repeated surgery for infection. The infection rate was 12.5% for grade/type IIIA open fractures, 45.8% for grade/type IIIB, and 50% for grade/type IIIC. Twenty-four of 50 fractures (48%) required subsequent surgery to facilitate fracture healing. Five fractures required amputation after attempted coverage. Seven of 24 fractures initially classified as grade/type IIIA and 10 of 24 fractures initially classified as grade/type IIIB ultimately required free tissue transfer or rotational muscle flap coverage. CONCLUSIONS: Infection and nonunion rates with the use of NPWT for temporary coverage of wounds associated with grade/type III open tibial shaft fractures are similar to those of historical controls, but this technique may be beneficial in decreasing the need for free tissue transfer or rotational muscle flap coverage.

Computer-assisted preoperative planning in the surgical treatment of acetabular fractures.

Displaced acetabular fractures are among the most complex of all orthopaedic injuries. Keys to accurate reduction and improved outcomes are accurate imaging studies and a complete understanding of the nature of the fracture. The orientation of complex fractures may be difficult to understand or conceptualize. Traditionally, surgeons have relied on orthogonal Judet views of the pelvis with computed tomography images as tools to use in order to formulate a preoperative plan; however, these modalities may not communicate subtle characteristics of the fracture. The expansion of the power and capabilities of three-dimensional (3D) computer reconstructions has been recognized most recently as a useful adjunct in preoperative planning. The case of a 61-year-old patient with a both-column acetabular fracture and vertically unstable pelvis--in which 3D computer reconstructions and a novel computer-assisted planning tool, Trauma CAD, were used in order to devise an accurate preoperative plan after fully understanding the nature of the injury--is presented.

Osteomyelitis and intraosteoblastic Staphylococcus aureus.

Chronic osteomyelitis is a disease process that is characterized not infrequently by periods of clinical quiescence interspersed by symptomatic episodes of varying duration and severity. These periods of clinical quiescence have been attributed to several possible factors, including effective host defenses that keep the process at bay as well as glycocalyceal sequestration of the implicated pathogen. Recent work has demonstrated a potential third explanation for this phenomenon, that is, intracellular incorporation of the pathogen within the host osteoblast. This is a report of a successful osteoblast cell culture demonstrating the facultative intraosteoblastic location of a human osteomyelitis Staphylococcus aureus isolate as well as its microscopic features.

The Impact of Negative Pressure Wound Therapy on Orthopaedic Infection.

By hastening the resolution of edema and improving local microcirculation, topical negative pressure wound therapy (TNP) aids the establishment of early wound coverage. Its use in the setting of type III open fractures is reviewed. The author's initial use of TNP for closed surgical incisions and how it morphed its way into being applied to closed surgical wounds with heightened likelihood for infection is presented. Several case studies are presented to illustrate the role and the technique for management of acute or subacute infections involving bone and implant.