Human platelet concentrates treated with microbicidal 405 nm light retain hemostasis activity

Chemical and UV light-based pathogen reduction technologies are currently in use for human platelet concentrates (PCs) to enhance safety from transfusion-transmitted infections. Relative to UV light, 405 nm violet-blue light in the visible spectrum is known to be less harmful. Hence, in this report for the first time, we have assessed the global hemostasis activity of PCs stored in plasma and the activities of six plasma coagulation factors (CFs) as a measure of in vitro hemostatic activity following exposure to the microbicidal 405 nm light. Apheresis PC samples collected from each screened human donor (n = 22) were used for testing of PCs and platelet poor plasma (PPP). Both PCs and PPPs were treated for 5 h with 405 nm light to achieve a previously established microbicidal light dose of 270 J/cm2. Activated partial thromboplastin time and prothrombin time-based potency assays using a coagulation analyzer and hemostatic capacity via Thromboelastography were analyzed. Thromboelastography analysis of the light-treated PCs and plasma present in the PCs showed little difference between the treated and untreated samples. Further, plasma present in the PCs during the light treatment demonstrated a better stability in potency assays for several coagulation factors compared to the plasma alone prepared from PCs first and subjected to the light treatment separately. Overall, PCs stored in plasma treated with 405 nm violet-blue light retain activity for hemostasis.

Enhanced antimicrobial efficacy and energy efficiency of low irradiance 405-nm light for bacterial decontamination

Due to its increased safety over ultraviolet light, there is interest in the development of antimicrobial violet-blue light technologies for infection control applications. To ensure compatibility with exposed materials and tissue, the light irradiances and dose regimes used must be suitable for the target application. This study investigates the antimicrobial dose responses and germicidal efficiency of 405 nm violet-blue light when applied at a range of irradiance levels, for inactivation of surface-seeded and suspended bacteria. Bacteria were seeded onto agar surfaces (101-108 CFUplate-1) or suspended in PBS (103-109 CFUmL-1) and exposed to increasing doses of 405-nm light (≤ 288 Jcm-2) using various irradiances (0.5-150 mWcm-2), with susceptibility at equivalent light doses compared. Bacterial reductions ≥ 96% were demonstrated in all cases for lower irradiance (≤ 5 mWcm-2) exposures. Comparisons indicated, on a per unit dose basis, that significantly lower doses were required for significant reductions of all species when exposed at lower irradiances: 3-30 Jcm-2/0.5 mWcm-2 compared to 9-75 Jcm-2/50 mWcm-2 for low cell density (102 CFUplate-1) surface exposures and 22.5 Jcm-2/5 mWcm-2 compared to 67.5 Jcm-2/150 mWcm-2 for low density (103 CFUmL-1) liquid exposures (P ≤ 0.05). Similar patterns were observed at higher densities, excluding S. aureus exposed at 109 CFUmL-1, suggesting bacterial density at predictable levels has minimal influence on decontamination efficacy. This study provides fundamental evidence of the greater energy efficacy of 405-nm light for inactivation of clinically-significant pathogens when lower irradiances are employed, further supporting its relevance for practical decontamination applications.

Viricidal Efficacy of a 405-nm Environmental Decontamination System for Inactivation of Bacteriophage Phi6: Surrogate for SARS-CoV-2

The highly transmittable nature of SARS-CoV-2 has increased the necessity for novel strategies to safely decontaminate public areas. This study investigates the efficacy of a low irradiance 405-nm light environmental decontamination system for the inactivation of bacteriophage phi6 as a surrogate for SARS-CoV-2. Bacteriophage phi6 was exposed to increasing doses of low irradiance (~0.5 mW cm-2 ) 405-nm light while suspended in SM buffer and artificial human saliva at low (~103-4  PFU mL-1 ) and high (~107-8  PFU mL-1 ) seeding densities, to determine system efficacy for SARS-CoV-2 inactivation and establish the influence of biologically relevant suspension media on viral susceptibility. Complete/near-complete (≥99.4%) inactivation was demonstrated in all cases, with significantly enhanced reductions observed in biologically relevant media (P < 0.05). Doses of 43.2 and 172.8 J cm-2 were required to achieve ~3 log10 reductions at low density, and 97.2 and 259.2 J cm-2 achieved ~6 log10 reductions at high density, in saliva and SM buffer, respectively: 2.6-4 times less dose was required when suspended in saliva compared to SM buffer. Comparative exposure to higher irradiance (~50 mW cm-2 ) 405-nm light indicated that, on a per unit dose basis, 0.5 mW cm-2 treatments were capable of achieving up to 5.8 greater log10 reductions with up to 28-fold greater germicidal efficiency than that of 50 mW cm-2 treatments. These findings establish the efficacy of low irradiance 405-nm light systems for inactivation of a SARS-CoV-2 surrogate and demonstrate the significant enhancement in susceptibility when suspended in saliva, which is a major vector in COVID-19 transmission.

Laboratory evaluation of the broad-spectrum antibacterial efficacy of a low-irradiance visible 405-nm light system for surface-simulated decontamination

Purpose

Lighting systems which use visible light blended with antimicrobial 405-nm violet-blue light have recently been developed for safe continuous decontamination of occupied healthcare environments. This paper characterises the optical output and antibacterial efficacy of a low irradiance 405-nm light system designed for environmental decontamination applications, under controlled laboratory conditions.

Methods

In the current study, the irradiance output of a ceiling-mounted 405-nm light source was profiled within a 3×3×2 m (18 m3) test area; with values ranging from 0.001-2.016 mWcm-2. To evaluate antibacterial efficacy of the light source for environmental surface decontamination, irradiance levels within this range (0.021-1 mWcm-2) at various angular (Δ ϴ=0-51.3) and linear (∆s=1.6-2.56 m) displacements from the source were used to generate inactivation kinetics, using the model organism, Staphylococcus aureus. Additionally, twelve bacterial species were surface-seeded and light-exposed at a fixed displacement below the source (1.5 m; 0.5 mWcm-2) to demonstrate broad-spectrum efficacy at heights typical of high touch surfaces within occupied settings.

Results

Results demonstrate that significant (P≤0.05) inactivation was successfully achieved at all irradiance values investigated, with spatial positioning from the source affecting inactivation, with greater times required for inactivation as irradiance decreased. Complete/near-complete (≥93.28%) inactivation of all bacteria was achieved following exposure to 0.5 mWcm-2 within exposure times realistic of those utilised practically for whole-room decontamination (2-16 h).

Conclusion

This study provides fundamental evidence of the efficacy, and energy efficiency, of low irradiance 405-nm light for bacterial inactivation within a controlled laboratory setting, further justifying its benefits for practical infection control applications.

INBONE Total Ankle System: Clinical and Radiographic Outcomes

Category:

Ankle Arthritis

Introduction/Purpose:

Ankle arthroplasties have undergone several generations of development since their initial introduction. Newer technologies in design have offered prosthetics which were more mobile and closer in articulation to human ankle joints. This includes increased motion of the coronal and sagittal planes, as well as less wear-and-tear of the prosthesis. Currently, second generation ankle arthroplasties have only shown promising results intermediately, and there has been very little research looking into the long term results of these devices. The INBONE total ankle system is a relatively new addition to the market that specifically has not been well researched. This project is aimed to outline their morbidly and mortality, as well as compare the long term results to other commonly used implants with data available.

Methods:

The study will be a retrospective, single-site cohort of past patients who have undergone INBONE total arthroplasty by Drs. Anderson, Bohay and Maskill at Orthopaedic Associates of Michigan (OAM). Pre-op indications will be evaluated, as well as lengthy post-op periods including 2 week, 6 week, 8 week, 1 year, and 2+ years follow up scores. Charts will be reviewed for inclusion and exclusion criteria. This includes demographic information, operative information, complications, reoperations, radiographic outcomes, and post-operative satisfaction scores. These scores include functional characteristics of ankle arthritis patients including pain level, walking distances, gait stability, varus/valgus stress, dorsi/plantarflexion ankle motion arc, hindfoot stability, and ankle alignment (AOFAS Score Criteria).

Results:

Study still in progress, results pending.

Conclusion:

Study still in progress, results pending.

Treatment of Hallux Rigidus: Comparison of Hemiarthroplasty with Cartiva Implant, Allograft Interpositional Arthroplasty, and Arthrodesis

Category:

Midfoot/Forefoot; Other

Introduction/Purpose:

Hallux Rigidus (HR) can cause pain with motion, enlarged joint, decreased joint space, subchondral sclerosis, osteophyte formation and restricted joint mobility, limiting patient physical activity. A modern technique for the treatment of HR is 1st MTP hemiarthroplasty with the use of a Cartiva synthetic cartilage implant. The Cartiva implant is designed to imitate natural cartilage; this allows patients to maintain motion in the 1st MTP joint. Current scientific literature reporting early outcomes of the procedure is sparse and mixed. This discrepancy and the overall scarcity of data indicates the need for further analysis. The purpose of this study is to compare improvement in VAS with 1st MTP hemiarthroplasty with the Cartiva implant, allograft interposition arthroplasty and fusion in patients who failed conservative management or cheilectomy.

Methods:

This study evaluated subjects who underwent interpositional arthroplasty, arthrodesis, or hemiarthroplasty with the Cartiva implant from January 2008 to April 2020, with a minimum of one year documented follow-up. All subjects were 18 years of age and older, diagnosed Hallux rigidus with pain, had a decrease in 1st MTP motion, and had X-ray findings consistent with decreased joint space. Patient data collected includes age, gender, ethnicity, occupation, height, weight, BMI, diabetes status, rheumatoid arthritis status, smoking, co-morbid conditions, medication, activity of choice, duration of symptoms, and operative data. Pre-operative and post- operative Visual Analog Scale (VAS) pain scores were compared between groups. Pain, function, and alignment between groups were also evaluated, pre-operatively and post- operatively, using the AOFAS Midfoot Scale. Secondary objectives evaluated include surgical complications, surgical revision, and X-rays.

Results:

One hundred patients with 12 months of post-operative follow-up were included in this study: 52 hemiarthroplasty with Cartiva implant patients (Group A), 24 arthrodesis patients (Group B), and 24 interpositional arthroplasty patients (Group C). The mean age of patients was 57.12 years (range 35-95). Average VAS pain scores for Group A was 3.78 (0-9), for Group B was 2.71 (0-10), and Group C was 3.67 (0-8). The average AOFAS score for Group A was 63.36 (30-95), for Group B was 60.98 (32- 83), and Group C was 60.13 (31-83). Pre-operative average VAS pain scores were 4.86 (Group A), 2.32 (Group B), and 5.58 (Group C). Post-operative average VAS pain scores were 2.69 (Group A), 0.91 (Group B), and 1.75 (Group C). Pre-operative average AOFAS scores were 59.52 (Group A), 48 (Group B), and 47.25 (Group C). Post-operative average AOFAS scores were 67.20 (Group A), 73.96 (Group B), and 73 (Group C).

Conclusion:

Preliminary data shows the greatest reduction in VAS pain scores in the interpositional arthroplasty group. The greatest improvement in derived AOFAS score was seen in the arthrodesis and interpositional arthroplasty groups, indicating a better overall combination of post-operative pain, function, and alignment when compared to patients who underwent hemiarthroplasty with Cartiva implant. While this study is not yet complete, it appears that hemiarthroplasty with Cartiva implant may allow patients to maintain motion in the 1st MTP joint, but at the cost of increased post-operative pain.

Violet-blue 405-nm Light-based Photoinactivation for Pathogen Reduction of Human Plasma Provides Broad Antibacterial Efficacy Without Visible Degradation of Plasma Proteins

In transfusion medicine, bacterial contamination can occur in ex vivo stored blood plasma, and there are continued efforts to improve blood safety and reduce the risk of transfusion-transmitted infections. Visible 405-nm violet-blue light has demonstrated potential for in situ pathogen reduction in ex vivo stored plasma and platelet concentrates. This study investigates the broad-spectrum antibacterial efficacy and compatibility potential of 405-nm light for treatment of blood plasma. Human plasma seeded with bacteria at a range of densities (10¹ -10³ , 10⁴ -10⁶ , 10⁷ -10⁸  CFU mL^-1 ) was exposed to 360 J cm^-2 405-nm light (1 h at 0.1 W cm^-2 ), with this fixed dose selected based on the initial analysis of inactivation kinetics. One-dimensional protein mobility analysis and measurement of advanced oxidation protein products (AOPP) was conducted to evaluate compatibility of the antimicrobial dose with plasma proteins and, identify upper levels at which protein degradation can be detected. Broad-spectrum antibacterial efficacy was observed with a fixed treatment of 360 J cm^-2 , with 98.9-100% inactivation achieved across all seeding densities for all organisms, except E. coli, which achieved 95.1-100% inactivation. At this dose (360 J cm^-2 ), no signs of protein degradation occurred. Overall, 405-nm light shows promise for broad-spectrum bacterial inactivation in blood plasma, while preserving plasma protein integrity.

Complications Associated with Peripheral Nerve Blocks

Outpatient orthopedic surgery is gradually becoming the standard across the country, as it has been found to significantly lower costs without compromising patient care. Peripheral nerve blocks (PNBs) are largely what have made this transition possible by providing patients excellent pain control in the immediate postoperative period. However, with the increasing use of PNBs, it is important to recognize that they are not without complications. Although rare, these complications can cause patients a significant amount of morbidity. It is important for surgeons to know the risks of peripheral nerve blocks and to inform their patients.

Comparing 4-Year Changes in Patient-Reported Outcomes Following Ankle Arthroplasty and Arthrodesis

BACKGROUND

The rate of total ankle arthroplasty (TAA) is increasing relative to ankle arthrodesis (AA) for patients seeking surgical treatment for end-stage ankle arthritis. Patients and providers would benefit from a more complete understanding of the rate of improvement, the average length of time to achieve maximal function and minimal pain, and whether there is a greater decline in function or an increase in pain over time following TAA compared with AA. The objectives of this study were to compare treatment changes in overall physical and mental function and ankle-specific function, as well as pain intensity at 48 months after TAA or AA in order to determine if the improvements are sustained.

METHODS

This was a multisite prospective cohort study that included 517 participants (414 TAA and 103 AA) who presented for surgical treatment. Participants were compared 48 months after surgery using the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living and Sports subscales (0 to 100 points), the Short Form-36 (SF-36) Physical and Mental Component Summary (PCS and MCS) scores (0 to 100 points), and pain scores (0 to 10 points).

RESULTS

Both groups achieved significant improvement in the 2 FAAM measures, the SF-36 PCS score, and all of the pain measures at 48 months after surgey (p < 0.001). Mean improvements from baseline in patients undergoing TAA for the FAAM Activities of Daily Living, FAAM Sports, and SF-36 scores were at least 9 points, 8 points, and 3.5 points, respectively, which were higher than in those undergoing AA. Mean improvements in worst and average pain were at least 0.9 point higher in patients undergoing TAA than in those undergoing AA at 12, 24, and 36 months. These differences were attenuated by 48 months. For both treatments, all improvements from baseline to 24 months had been maintained at 48 months.

CONCLUSIONS

When both procedures are performed by the same group of surgeons, patients who undergo TAA or AA for end-stage ankle arthritis have significant improvement in overall function, ankle-specific function, and pain at 48 months after surgery, with better functional improvement in the TAA group.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Complete Inactivation of Blood Borne Pathogen Trypanosoma cruzi in Stored Human Platelet Concentrates and Plasma Treated With 405 nm Violet-Blue Light

The introduction of pathogen reduction technologies (PRTs) to inactivate bacteria, viruses and parasites in donated blood components stored for transfusion adds to the existing arsenal toward reducing the risk of transfusion-transmitted infectious diseases (TTIDs). We have previously demonstrated that 405 nm violet-blue light effectively reduces blood-borne bacteria in stored human plasma and platelet concentrates. In this report, we investigated the microbicidal effect of 405 nm light on one important bloodborne parasite Trypanosoma cruzi that causes Chagas disease in humans. Our results demonstrated that a light irradiance at 15 mWcm⁻² for 5 h, equivalent to 270 Jcm⁻², effectively inactivated T. cruzi by over 9.0 Log₁₀, in plasma and platelets that were evaluated by a MK2 cell infectivity assay. Giemsa stained T. cruzi infected MK2 cells showed that the light-treated parasites in plasma and platelets were deficient in infecting MK2 cells and did not differentiate further into intracellular amastigotes unlike the untreated parasites. The light-treated and untreated parasite samples were then evaluated for any residual infectivity by injecting the treated parasites into Swiss Webster mice, which did not develop infection even after the animals were immunosuppressed, further demonstrating that the light treatment was completely effective for inactivation of the parasite; the light-treated platelets had similar in vitro metabolic and biochemical indices to that of untreated platelets. Overall, these results provide a proof of concept toward developing 405 nm light treatment as a pathogen reduction technology (PRT) to enhance the safety of stored human plasma and platelet concentrates from bloodborne T. cruzi, which causes Chagas disease.

Non-ionizing 405 nm Light as a Potential Bactericidal Technology for Platelet Safety: Evaluation of in vitro Bacterial Inactivation and in vivo Platelet Recovery in Severe Combined Immunodeficient Mice

Bacterial contamination of ex vivo stored platelets is a cause of transfusion-transmitted infection. Violet-blue 405 nm light has recently demonstrated efficacy in reducing the bacterial burden in blood plasma, and its operational benefits such as non-ionizing nature, penetrability, and non-requirement for photosensitizing agents, provide a unique opportunity to develop this treatment for in situ treatment of ex vivo stored platelets as a tool for bacterial reduction. Sealed bags of platelet concentrates, seeded with low-level Staphylococcus aureus contamination, were 405 nm light-treated (3–10 mWcm⁻²) up to 8 h. Antimicrobial efficacy and dose efficiency was evaluated by quantification of the post-treatment surviving bacterial contamination levels. Platelets treated with 10 mWcm⁻² for 8 h were further evaluated for survival and recovery in severe combined immunodeficient (SCID) mice. Significant inactivation of bacteria in platelet concentrates was achieved using all irradiance levels, with 99.6–100% inactivation achieved by 8 h (P < 0.05). Analysis of applied dose demonstrated that lower irradiance levels generally resulted in significant decontamination at lower doses: 180 Jcm⁻²/10 mWcm⁻² (P = 0.008) compared to 43.2 Jcm⁻²/3 mWcm⁻² (P = 0.002). Additionally, the recovery of light-treated platelets, compared to non-treated platelets, in the murine model showed no significant differences (P = >0.05). This report paves the way for further comprehensive studies to test 405 nm light treatment as a bactericidal technology for stored platelets.

Effectiveness and Safety of Ankle Arthrodesis Versus Arthroplasty: A Prospective Multicenter Study

BACKGROUND

Newer designs and techniques of total ankle arthroplasty (TAA) have challenged the assumption of ankle arthrodesis (AA) as the primary treatment for end-stage ankle arthritis. The objective of this study was to compare physical and mental function, ankle-specific function, pain intensity, and rates of revision surgery and minor complications between these 2 procedures and to explore heterogeneous treatment effects due to age, body mass index (BMI), patient sex, comorbidities, and employment on patients treated by 1 of these 2 methods.

METHODS

This was a multisite prospective cohort study comparing outcomes of surgical treatment of ankle arthritis. Subjects who presented after nonoperative management had failed received either TAA or AA using standard-of-treatment care and rehabilitation. Outcomes included the Foot and Ankle Ability Measure (FAAM), Short Form-36 (SF-36) Physical and Mental Component Summary (PCS and MCS) scores, pain, ankle-related adverse events, and treatment success.

RESULTS

Five hundred and seventeen participants underwent surgery and completed a baseline assessment. At 24 months, the mean improvement in FAAM activities of daily living (ADL) and SF-36 PCS scores was significantly greater in the TAA group than in the AA group, with a difference between groups of 9 points (95% confidence interval [CI] = 3, 15) and 4 points (95% CI = 1, 7), respectively. The crude incidence risks of revision surgery and complications were greater in the AA group; however, these differences were no longer significant after adjusting for age, sex, BMI, and Functional Comorbidity Index (FCI). The treatment success rate was greater after TAA than after AA for those with an FCI of 4 (80% versus 62%) and not fully employed (81% versus 58%) but similar for those with an FCI score of 2 (81% versus 77%) and full-time employment (79% versus 78%).

CONCLUSIONS

At 2-year follow-up, both AA and TAA were effective. Improvement in several patient-reported outcomes was greater after TAA than after AA, without a significant difference in the rates of revision surgery and complications.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Step Activity After Surgical Treatment of Ankle Arthritis

BACKGROUND

Ambulatory activity is reduced in patients with ankle arthritis. In this study, we measured step activity over time in 2 treatment groups and secondarily compared step activity with results of patient-reported outcome measures (PROMs).

METHODS

Patients who were treated with either ankle arthrodesis or ankle arthroplasty wore a step activity monitor preoperatively and at 6, 12, 24, and 36 months postoperatively. Changes from preoperative baseline in total steps per day and per-day metrics of low, medium, and high-activity step counts were measured in both treatment groups. Step activity was compared with each subject's PROM scores as reported on the Musculoskeletal Function Assessment (MFA) and the Short Form-36 (SF-36) physical function and bodily pain subscales.

RESULTS

Of the 3 activity levels, combined group high-activity step counts showed the greatest increase (mean of 278 steps [95% confidence interval (CI), 150 to 407 steps], a 46% improvement from preoperatively). At 6 months, the mean high-activity step improvement for the arthroplasty group was 194 steps compared with a mean decline of 44 steps for the arthrodesis group (mean 238-step difference [95% CI, -60 to 536 steps]). By 36 months postoperatively, the greater improvement in high-activity steps for the arthroplasty versus the arthrodesis group was no longer present. There were no significant pairwise differences in improvement based on surgical treatment method at any individual follow-up time point. For a within-patient increase of 1,000 total steps, there was a mean change in the MFA, SF-36 physical function, and SF-36 bodily pain scores of -1.8 (95% CI, -2.4 to -1.2), 3.8 (95% CI, 2.8 to 4.8), and 2.8 (95% CI, 1.8 to 3.9), respectively (p < 0.0001 for all associations). There was no evidence that the association differed by study visit, or by study visit and surgical procedure interaction (p > 0.10).

CONCLUSIONS

Surgical treatment of ankle arthritis significantly improves ambulatory activity, with greater change occurring at high activity levels. Improvement may occur more quickly following arthroplasty than arthrodesis, but at 3 years, we detected no significant difference between the 2 procedures. Step counts, while associated with PROMs, do not parallel them, and thus may be a useful supplementary measure, particularly in longitudinal studies.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Continuous monitoring of aerial bioburden within intensive care isolation rooms and identification of high-risk activities

Background

The spread of pathogens via the airborne route is often underestimated, and little is known about the extent to which airborne microbial contamination levels vary throughout the day and night in hospital facilities.

Aims

To evaluate airborne contamination levels within intensive care unit (ICU) isolation rooms over 10–24-h periods in order to improve understanding of the variability of environmental aerial bioburden, and the extent to which ward activities may contribute.

Methods

Environmental air monitoring was conducted within occupied and vacant inpatient isolation rooms. A sieve impactor sampler was used to collect 500-L air samples every 15 min over 10-h (08:00–18:00 h) and 24-h (08:00–08:00 h) periods. Samples were collected, room activity was logged, and bacterial contamination levels were recorded as colony-forming units (cfu)/m³ air.

Findings

A high degree of variability in levels of airborne contamination was observed across all scenarios in the studied isolation rooms. Air bioburden increased as room occupancy increased, with air contamination levels highest in rooms occupied for the longest time during the study (10 days) (mean 104.4 cfu/m³, range 12–510 cfu/m³). Counts were lowest in unoccupied rooms (mean 20 cfu/m³) and during the night.

Conclusion

Peaks in airborne contamination were directly associated with an increase in activity levels. This study provides the first clear evidence of the extent of variability in microbial airborne levels over 24-h periods in ICU isolation rooms, and found direct correlation between microbial load and ward activity.

Frequency and Impact of Adverse Events in Patients Undergoing Surgery for End-Stage Ankle Arthritis

BACKGROUND

This study summarized the frequency and functional impact of adverse events (AEs) that occur after surgery for end-stage ankle arthritis (ESAA) to inform decision making.

METHODS

This was a multisite prospective cohort study to compare ankle arthroplasty to ankle arthrodesis in the treatment of ESAA among 6 participating sites. We compared the risk and impact of nonankle AEs and ankle-specific AEs versus no AEs controlling for potential confounding factors, including operative procedure using multinomial logistic regression. We estimated differences in postoperative functional outcomes by AE occurrence using linear mixed effects regression. Among 517 patients who had surgery for ankle arthritis and completed the full baseline assessment, follow-up scores were available in 494 (95%) patients.

RESULTS

There were a total of 628 reported AEs (477 in the arthroplasty group and 151 in the arthrodesis group). These occurred in 261 (63%) arthroplasty patients and 67 (65%) arthrodesis patients. There were 50 (8%) ankle-specific AEs. The risk of an ankle-specific AE was slightly higher in the arthrodesis group versus the arthroplasty group, odds ratio (OR) 1.84, 95% confidence interval (CI, 0.85, 3.98). The OR for the risk of non-ankle-specific AE versus no AE was 0.96, 95% CI (0.57, 1.61) for those receiving arthrodesis compared to arthroplasty. Compared to patients with no AEs, those experiencing ankle-specific AEs had significantly less improvement in Foot and Ankle Ability Measure Sports and activities of daily living (ADL) subscores and worst pain outcomes; however, both groups improved significantly in all measures except mental health.

CONCLUSIONS

Ankle-specific AEs were infrequent and only weakly associated with operative procedure. Although patients improved in all functional outcomes except mental health, regardless of AE occurrence, ankle-specific AEs negatively impacted patient improvement compared to those with no AEs or a nonankle AE. The logistical effort and cost of tracking nonankle AEs does not seem to be justified.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Coupling free radical catalysis, climate change, and human health

We present the chain of mechanisms linking free radical catalytic loss of stratospheric ozone, specifically over the central United States in summer, to increased climate forcing by CO2 and CH4 from fossil fuel use. This case directly engages detailed knowledge, emerging from in situ aircraft observations over the polar regions in winter, defining the temperature and water vapor dependence of the kinetics of heterogeneous catalytic conversion of inorganic chlorine (HCl and ClONO2) to free radical form (ClO). Analysis is placed in the context of irreversible changes to specific subsystems of the climate, most notably coupled feedbacks that link rapid changes in the Arctic with the discovery that convective storms over the central US in summer both suppress temperatures and inject water vapor deep into the stratosphere. This places the lower stratosphere over the US in summer within the same photochemical catalytic domain as the lower stratosphere of the Arctic in winter engaging the risk of amplifying the rate limiting step in the ClO dimer catalytic mechanism by some six orders of magnitude. This transitions the catalytic loss rate of ozone in lower stratosphere over the United States in summer from HOx radical control to ClOx radical control, increasing the overall ozone loss rate by some two orders of magnitude over that of the unperturbed state. Thus we address, through a combination of observations and modeling, the mechanistic foundation defining why stratospheric ozone, vulnerable to increased climate forcing, is one of the most delicate aspects of habitability on the planet.

Utilization of Computers in Clinical Practice - Role of Physician Networks: Preliminary Communication

This study examines the influence of physician networks on the utilization of computers in clinical practice. Data on patient referrals, consultations, professional discussions, and on-call coverage were collected from 24 physicians who comprise a private group practice. Their utilization of a computerized hospital medical information system (HIS) in caring for patients admitted to a 1160-bed private, university affiliated, teaching hospital was determined. A matrix representing the professional relations among these physicians was subjected to smallest space analysis, a form of multidimensional scaling. Also, a number of indices that describe structural and interactional properties of the network and individual physicians were computed. The three-dimensional representation of the network that resulted from the analysis suggests a two-step process of adoption and utilization of medical technology. Physicians who were engaged in outside professional activities and in the training of medical students and house staff were more likely to utilize the system in caring for patients. These physicians, who were more centrally located and dominant in the referral and consultation process, were more likely to influence the practice patterns of their colleagues. The use of network analysis to identify influential physicians whose involvement is essential to the success of efforts aimed at introducing computers into clinical practice is discussed.

Comparison of Treatment Outcomes of Arthrodesis and Two Generations of Ankle Replacement Implants

BACKGROUND

We analyzed self-reported outcomes in a prospective cohort of patients treated with ankle arthrodesis or total ankle replacement (TAR) during a time of transition from older to newer-generation TAR implants.

METHODS

We performed a prospective cohort study comparing outcomes in 273 consecutive patients treated for ankle arthritis with arthrodesis or TAR between 2005 and 2011. Adult patients with end-stage ankle arthritis who were able to walk and willing and able to respond to surveys were included in the study. Patients were excluded when they had another lower-limb problem that might affect walking. At baseline and at 6, 12, 24, and 36-month follow-up visits, participants completed a pain score, a Musculoskeletal Function Assessment (MFA), and a Short Form-36 (SF-36) survey.

RESULTS

There was significant mean improvement in most outcomes after surgery regardless of procedure. In general, the greatest improvement occurred during the first 6 months of follow-up. Linear mixed-effects regression adjusted for differences at baseline in age, body mass index (BMI), and surgery type showed that at 6 months the scores were improved by a mean (and standard error) of 12.6 ± 0.7 (33%) on the MFA, 22.0 ± 1.4 (56%) on the SF-36 Physical Functioning (PF) scale, 32.4 ± 1.6 (93%) on the SF-36 Bodily Pain (BP) scale, and 4.0 ± 0.2 (63%) on the pain rating scale. The mean improvements in the MFA and SF-36 PF scores over the 3-year follow-up period were significantly better after the TARs than after the arthrodeses, with differences between the 2 groups of 3.6 ± 1.6 (p = 0.023) and 7.5 ± 2.9 (p = 0.0098), respectively. The differences between the 2 groups were slightly greater when only the newer TAR devices were compared with the arthrodeses (MFA = 3.8 ± 1.8 [p = 0.031], SF-36 PF = 8.8 ± 3.3 [p = 0.0074], SF-36 BP = 7.3 ± 3.6 [p = 0.045], and pain score = 0.8 ± 0.4 [p = 0.038]).

CONCLUSIONS

Patients reported improved comfort and function after both surgical treatments. The average improvement in the MFA and SF-36 PF scores was better after TAR than after arthrodesis, particularly when the TAR had been done with later-generation implants. Younger patients had greater functional improvements than older patients.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Assessment of the potential for resistance to antimicrobial violet-blue light in Staphylococcus aureus

BACKGROUND

Antimicrobial violet-blue light in the region of 405 nm is emerging as an alternative technology for hospital decontamination and clinical treatment. The mechanism of action is the excitation of endogenous porphyrins within exposed microorganisms, resulting in ROS generation, oxidative damage and cell death. Although resistance to 405 nm light is not thought likely, little evidence has been published to support this. This study was designed to establish if there is potential for tolerance development, using the nosocomial pathogen Staphylococcus aureus as the model organism.

METHODS

The first stage of this study investigated the potential for S. aureus to develop tolerance to high-intensity 405 nm light if pre-cultured in low-level stress violet-blue light (≤1 mW/cm²) conditions. Secondly, the potential for tolerance development in bacteria subjected to repeated sub-lethal exposure was compared by carrying out 15 cycles of exposure to high-intensity 405 nm light, using a sub-lethal dose of 108 J/cm². Inactivation kinetics and antibiotic susceptibility were also compared.

RESULTS

When cultured in low-level violet-blue light conditions, S. aureus required a greater dose of high-intensity 405 nm light for complete inactivation, however this did not increase with multiple (3) low-stress cultivations. Repeated sub-lethal exposures indicated no evidence of bacterial tolerance to 405 nm light. After 15 sub-lethal exposures 1.2 and 1.4 log₁₀ reductions were achieved for MSSA and MRSA respectively, which were not significantly different to the initial 1.3 log₁₀ reductions achieved (P = 0.242 & 0.116, respectively). Antibiotic susceptibility was unaffected, with the maximum change in zone of inhibition being ± 2 mm.

CONCLUSIONS

Repeated sub-lethal exposure of non-proliferating S. aureus populations did not affect the susceptibility of the organism to 405 nm light, nor to antibiotics. Culture in low-level violet-blue light prior to 405 nm light exposure may increase oxidative stress responses in S. aureus, however, inactivation still occurs and results demonstrate that this is unlikely to be a selective process. These results demonstrate that tolerance from repeated exposure is unlikely to occur, and further supports the potential development of 405 nm light for clinical decontamination and treatment applications.

New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination

The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log₁₀ (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm^-2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.

Open Reduction and Internal Fixation Versus Primary Arthrodesis for Lisfranc Injuries

Management of injuries to the tarsometatarsal (Lisfranc) joint complex continues to generate heated debate. Arthrodesis of the Lisfranc joint complex has historically been reserved as a salvage procedure for failed treatment. Recently, primary arthrodesis has emerged as a viable treatment alternative to open reduction and internal fixation for these injuries. The objective of this article was to examine the current literature regarding open reduction and internal fixation versus primary arthrodesis of Lisfranc injuries.

Clinical and Histopathologic Characterization of Canine Chronic Ulcerative Stomatitis

Canine chronic ulcerative stomatitis, also known as chronic ulcerative paradental stomatitis, is a painful condition of the oral cavity. The purpose of this study was to determine if there are commonalities in clinical and radiographic features among patients, whether the histopathologic evaluation might inform the pathogenesis, and whether the condition appears similar to human oral mucosal diseases. To do this, we prospectively collected clinical, radiographic, and histopathologic data from 20 dogs diagnosed with the disease. Clinical data were based on a clinical disease activity index, oral and periodontal examination parameters, and full-mouth dental radiographs. The histopathological and immunohistochemical data were based on oral mucosal samples obtained from erosive or ulcerated areas. Our findings revealed that canine chronic stomatitis is clinically characterized by painful oral mucosal ulcers of varying size, pattern, appearance, and distribution, most often associated with teeth with early periodontitis. Histologic examination revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response and an immune-mediated pathogenesis is suspected. The clinical and histopathologic features of this chronic inflammatory mucosal disease in dogs resemble those of oral lichen planus in humans.

The Use of Allostem in Subtalar Fusions

Subtalar arthrodesis is the mainstay for treatment of a variety of hindfoot problems associated with arthritis, however with an unpredictable if not high rate of nonunion. This article covers the use of adipose-derived stem cells as an adjunct or alternative to autologous or other bone grafting materials. Promising development and encouraging data exist with respect to the use of adipose-derived mesenchymal stem cells for bone arthrodesis, which is discussed in more detail in the article.

Population-based risks of mortality and preterm morbidity by gestational age and birth weight

OBJECTIVE

The objective of this study is to examine the effect of small or large for gestational age (SGA/LGA) status on mortality and morbidity by gestational age.

STUDY DESIGN

Logistic binomial regression was used to calculate relative risks (RRs) and 95% confidence intervals for infant mortality and preterm morbidities for SGA or LGA compared with appropriately grown (AGA) deliveries stratified by gestational age group.

RESULTS

Compared with AGA infants of similar gestational age, SGA infants were at increased risk for infant mortality. Mortality risk was decreased for LGA infants born between 25 and 27 weeks (RR: 0.6) but increased for LGA infants born between 28 and 31 weeks (RR: 1.9). Risk of preterm morbidity was increased for SGA infants born between 28 and 38 weeks, but decreased for LGA infants born before 37 weeks.

CONCLUSION

This study demonstrates the importance of considering birth weight for gestational age when evaluating morbidity and mortality risks.

The effects of 405 nm light on bacterial membrane integrity determined by salt and bile tolerance assays, leakage of UV-absorbing material and SYTOX green labelling

Bacterial inactivation by 405 nm light is accredited to the photoexcitation of intracellular porphyrin molecules resulting in energy transfer and the generation of reactive oxygen species that impart cellular oxidative damage. The specific mechanism of cellular damage, however, is not fully understood. Previous work has suggested that destruction of nucleic acids may be responsible for inactivation; however, microscopic imaging has suggested membrane damage as a major constituent of cellular inactivation. This study investigates the membrane integrity of Escherichia coli and Staphylococcus aureus exposed to 405 nm light. Results indicated membrane damage to both species, with loss of salt and bile tolerance by S. aureus and E. coli, respectively, consistent with reduced membrane integrity. Increased nucleic acid release was also demonstrated in 405 nm light-exposed cells, with up to 50 % increase in DNA concentration into the extracellular media in the case of both organisms. SYTOX green fluorometric analysis, however, demonstrated contradictory results between the two test species. With E. coli, increasing permeation of SYTOX green was observed following increased exposure, with >500 % increase in fluorescence, whereas no increase was observed with S. aureus. Overall, this study has provided good evidence that 405 nm light exposure causes loss of bacterial membrane integrity in E. coli, but the results with S. aureus are more difficult to explain. Further work is required to gain greater understanding of the inactivation mechanism in different bacterial species, as there are likely to be other targets within the cell that are also impaired by the oxidative damage from photo-generated reactive oxygen species.

Early Weight Bearing Following First TMT Arthrodesis

Category:

Midfoot/Forefoot

Introduction/Purpose:

The modified Lapidus arthrodesis is an accepted method of correcting varying degrees of hallux valgus with or without associated first ray insufficiency. Improved operative techniques have led to more reliable outcomes and lower incidence of nonunion. As a result, the modified Lapidus procedure has increased in popularity. Historically, surgeons have followed cautious postoperative protocols, initially restricting weight bearing until bone consolidation is confirmed radiographically. More recently, an alternative approach to postoperative management has been proposed, allowing patients to bear weight as tolerated two weeks after surgery with the goal of improving patient compliance while minimizing postoperative disability. The purpose of this study is to compare outcomes of patients randomized to either early weight bearing or standard non-weight bearing postoperative course following modified Lapidus arthrodesis.

Methods:

We determined that at least 130 patients would need to be enrolled in this study to achieve statistical significance (p < 0.05). Beginning in 2012, patients with hallux valgus indicated for modified Lapidus arthrodesis were assigned to either the investigational Group A (early weight bearing) or to the control Group B (standard of care) by a random number generator. All patients underwent modified Lapidus arthrodesis by one of the three senior authors (JGA, DRB, JDM). Specific demographic, clinical, patient-centered, and radiographic data were collected during the preoperative visit, the operative procedure, and at defined intervals during the postoperative period. The primary outcome variable was defined as first tarsometatarsal joint fusion at six months.

Results:

To date, 100 subjects have been enrolled, 57 of whom (40 patients in Group A, 17 patients in Group B) have completed one year of follow up. At six months, 38/40 patients in Group A had achieved radiographic union, compared to 17/17 patients in Group B (p = 0.495). Smoking status, BMI, and age at surgery were not found to be significantly associated with rate of union in either group. Patients in Group A required less time to reach full weight bearing status (p < 0.001). At six weeks after surgery, Group A reported significantly higher levels of physical function and overall composite scores on the SF-36 questionnaire. The rate of adverse events was not significantly different between the two groups at any postoperative timepoint.

Conclusion:

Though data collection is ongoing, our results indicate that clinical, patient-centered, and radiographic outcomes were comparable following modified Lapidus arthrodesis in both the early weight bearing and standard of care patient groups. Early weight bearing does not appear to increase the rate of adverse events or significantly slow rate of fusion, and also reduces postoperative disability.

Cytotoxic responses to 405nm light exposure in mammalian and bacterial cells: Involvement of reactive oxygen species

Light at wavelength 405 nm is an effective bactericide. Previous studies showed that exposing mammalian cells to 405 nm light at 36 J/cm(2) (a bactericidal dose) had no significant effect on normal cell function, although at higher doses (54 J/cm(2)), mammalian cell death became evident. This research demonstrates that mammalian and bacterial cell toxicity induced by 405 nm light exposure is accompanied by reactive oxygen species production, as detected by generation of fluorescence from 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate. As indicators of the resulting oxidative stress in mammalian cells, a decrease in intracellular reduced glutathione content and a corresponding increase in the efflux of oxidised glutathione were observed from 405 nm light treated cells. The mammalian cells were significantly protected from dying at 54 J/cm(2) in the presence of catalase, which detoxifies H2O2. Bacterial cells were significantly protected by sodium pyruvate (H2O2 scavenger) and by a combination of free radical scavengers (sodium pyruvate, dimethyl thiourea (OH scavenger) and catalase) at 162 and 324 J/cm(2). Results therefore suggested that the cytotoxic mechanism of 405 nm light in mammalian cells and bacteria could be oxidative stress involving predominantly H2O2 generation, with other ROS contributing to the damage.

Comparative Sensitivity of Trichophyton and Aspergillus Conidia to Inactivation by Violet-Blue Light Exposure

OBJECTIVE

To investigate the use of 405 nm light for inhibiting the growth of selected species of dermatophytic and saprophytic fungi.

BACKGROUND DATA

The increasing incidence and resilience of dermatophytic fungal infections is a major issue, and alternative treatment methods are being sought.

METHODS

The sensitivity of the dermatophytic fungi Trichophyton rubrum and Trichophyton mentagrophytes to 405 nm violet-blue light exposure was investigated, and the results compared with those obtained with the saprophytic fungus Aspergillus niger. Microconidia of T. rubrum and T. mentagrophytes and conidia of A. niger were seeded onto Sabauroud dextrose agar plates and irradiated with 405 nm light from an indium-gallium-nitride 99-DIE light-emitting diode (LED) array and the extent of inhibition was measured.

RESULTS

Germination of the microconidia of the Trichophyton species was completely inhibited using an irradiance of 35 mW/cm(2) for 4 h (dose of 504 J/cm(2)). A. niger conidia showed greater resistance, and colonial growth developed after light exposure. In liquid suspension tests, 405 nm light dose levels of 360, 720, and 1440 J/cm(2) resulted in complete inactivation of T. rubrum microconidia, whereas A. niger showed greater resistance, and at the highest dose level applied (1440 J/cm(2)) although A niger hyphae were completely inactivated, only a 3-log10 reduction of a 5-log10 conidial suspension was achieved.

CONCLUSIONS

The study results demonstrate the relatively high sensitivity of Trichophyton microconidia to 405 nm violet-blue light, and this is may be of potential interest regarding the control and treatment of dermatophyte infections.

Complications After Popliteal Block for Foot and Ankle Surgery

BACKGROUND

A popliteal nerve block is a common analgesic procedure for patients undergoing surgery on their knee, foot, or ankle. This procedure carries less risk in a surgical setting compared with other forms of anesthesia such as a spinal block. Previous reports demonstrated few to no complications with the use of this nerve block, but it is unclear whether these data are consistent with the recent increase in use of this analgesic procedure for lower extremity surgery.

METHODS

Retrospectively, a busy orthopedic foot and ankle practice performed a chart review examining for postoperative neuropathic complications possibly related to the popliteal nerve block. The 1014 patients who had undergone a popliteal block for foot and/or ankle orthopedic surgery were analyzed for short and long-term neuropathic complications. The collected data consisted of tourniquet time, pressure, and location as well as the method of finding the fossa nerve, adjuncts used, and patient medical history. Data were analyzed using chi-square, Fisher's exact, and t tests for analysis with a significance value of P < .05.

RESULT

Of these 1014 patients, 52 patients (5%) developed deleterious symptoms likely resulting from their popliteal block, and 7 (0.7%) of these were unresolved after their last follow-up. No immediately apparent underlying causes were determined for these complications.

CONCLUSION

The frequency of a neuropathic complication following a popliteal nerve block was notably higher in the early postoperative period than indicated in the past. The proportion of patients with unresolved neuropathic symptoms at last follow-up is comparable to that previously reported in the literature.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Over-Tightening of the Syndesmosis After Ankle Fracture: A Case Report

CASE

An eighteen-year-old patient sustained a fracture-dislocation of the left ankle while playing rugby. The fracture was treated in the emergency department with closed reduction and splinting, followed by open reduction and internal fixation. Subsequently, increased tibiotalar clear space was noted radiographically. Coronal computed tomography images confirmed distal distraction of the talus. This was determined to have resulted from "over-tightening" the syndesmosis. Our surgical treatment consisted of minute manual repositioning of the talus.

CONCLUSION

We advise meticulous scrutiny of intraoperative radiographs to evaluate potential talar distraction. Additionally, comparison radiographs of the contralateral ankle can be an essential component of preoperative and intraoperative assessment of ankle fractures with syndesmotic disruption.

Inactivation of micro-organisms isolated from infected lower limb arthroplasties using high-intensity narrow-spectrum (HINS) light

High-intensity narrow-spectrum (HINS) light is a novel violet-blue light inactivation technology which kills bacteria through a photodynamic process, and has been shown to have bactericidal activity against a wide range of species. Specimens from patients with infected hip and knee arthroplasties were collected over a one-year period (1 May 2009 to 30 April 2010). A range of these microbial isolates were tested for sensitivity to HINS-light. During testing, suspensions of the pathogens were exposed to increasing doses of HINS-light (of 123mW/cm(2) irradiance). Non-light exposed control samples were also used. The samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation (greater than 4-log10 reduction) was achieved for all of the isolates. The typical inactivation curve showed a slow initial reaction followed by a rapid period of inactivation. The doses of HINS-light required ranged between 118 and 2214 J/cm(2). Gram-positive bacteria were generally found to be more susceptible than Gram-negative. As HINS-light uses visible wavelengths, it can be safely used in the presence of patients and staff. This unique feature could lead to its possible use in the prevention of infection during surgery and post-operative dressing changes. Cite this article: Bone Joint J 2015;97-B:283-8.

Gastrocnemius recession

The Grand Rapids Arch Collapse classifications create a novel system for categorizing and correlating numerous common foot and ankle conditions related to a falling arch. The algorithm for treating these conditions is exceptionally replicable and has excellent outcomes. Gastrocnemius equinus diagnosis plays a crucial role in the pathology of arch collapse. A contracture of the gastrocnemius muscle is increasingly recognized as the cause of several foot and ankle conditions. The authors have expanded their indications for gastrocnemius recession to include arch pain without radiographic abnormality, calcaneus apophysitis, plantar fasciitis/fibromas, Achilles tendonosis, early-onset diabetic Charcot arthropathy, and neuropathic forefoot ulcers.

Inactivation of Streptomyces phage ɸC31 by 405 nm light: Requirement for exogenous photosensitizers?

Exposure to narrowband violet-blue light around 405 nm wavelength can induce lethal oxidative damage to bacteria and fungi, however effects on viruses are unknown. As photosensitive porphyrin molecules are involved in the microbicidal inactivation mechanism, and since porphyrins are absent in viruses, then any damaging effects of 405 nm light on viruses might appear unlikely. This study used the bacteriophage ɸC31, as a surrogate for non-enveloped double-stranded DNA viruses, to establish whether 405 nm light can induce virucidal effects. Exposure of ɸC31 suspended in minimal media, nutrient-rich media, and porphyrin solution, demonstrated differing sensitivity of the phage. Significant reductions in phage titer occurred when exposed in nutrient-rich media, with ~3-, 5- and 7-log₁₀ reductions achieved after exposure to doses of 0.3, 0.5 and 1.4 kJ/cm², respectively. When suspended in minimal media a 0.3-log₁₀ reduction (P = 0.012) occurred after exposure to 306 J/cm²: much lower than the 2.7- and > 2.5-log₁₀ reductions achieved with the same dose in nutrient-rich, and porphyrin-supplemented media, suggesting inactivation is accelerated by the photo-activation of light-sensitive components in the media. This study provides the first evidence of the interaction of narrowband 405 nm light with viruses, and demonstrates that viral susceptibility to 405 nm light can be significantly enhanced by involvement of exogenous photosensitive components. The reduced susceptibility of viruses in minimal media, compared with that of other microorganisms, provides further evidence that the antimicrobial action of 405 nm light is predominantly due to the photo-excitation of endogenous photosensitive molecules such as porphyrins within susceptible microorganisms.

Characterization of the AWARE 10 two-gigapixel wide-field-of-view visible imager

System requirements for many military electro-optic and IR camera systems reflect the need for both wide-field-of-view situational awareness as well as high-resolution imaging for target identification. In this work we present a new imaging system architecture designed to perform both functions simultaneously and the AWARE 10 camera as an example at visible wavelengths. We first describe the basic system architecture and user interface followed by a laboratory characterization of the system optical performance. We then describe a field experiment in which the camera was used to identify several maritime targets at varying range. The experimental results indicate that users of the system are able to correctly identify ~10 m targets at between 4 and 6 km with 70% accuracy.

The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10(12). The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A(2)Π3/2 (v(') = 2) ← X(2)Π3/2 (v(″) = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

Exothermic properties of plaster-synthetic composite casts

PURPOSE

Plaster casts can cause burns. Synthetic casts do not. Composite plaster-synthetic casts have not been thoroughly evaluated. This study analyzed the temperature from plaster casts compared with composite casts in a variety of in vitro conditions that would simulate clinical practice.

METHODS

A Pyrex cylinder filled with constant body temperature circulating water simulated a human extremity. Circumferential casts, of either plaster or composite construction (plaster inner layer with outer synthetic layer), were applied to the model. Peak temperatures generated by the exothermic reactions were studied relative to the following variables: dip water temperature (24 °C versus 40 °C), cast thickness (16, 30, and 34 ply), and delayed (5-min) versus immediate application of the synthetic outer layers. Peak temperatures from the all-plaster casts were compared with the composite casts of the same thickness. Finally, the relative cast strength was determined.

RESULTS

Potentially dangerous high temperatures were measured only when 40 °C dip water was used or when thick (30- or 34-ply) casts were made. Cast strength increased with increasing cast thickness. However, the presence of synthetics in the composite casts layers did not increase cast strength in every case.

CONCLUSION

When applying composite casts, the outer synthetic layers should be applied several minutes after the plaster to minimize temperature rise. Composite casts do not routinely generate peak temperatures higher than plaster casts of similar thickness. Because the skin of children and the elderly is more temperature-sensitive than average adult skin, extra care should be taken to limit the exothermic reaction when casting children and the elderly: clean, room temperature dip water, minimal required cast thickness, avoidance of insulating pillows/blankets while the cast is drying.

Differential sensitivity of osteoblasts and bacterial pathogens to 405-nm light highlighting potential for decontamination applications in orthopedic surgery

Healthcare associated infections pose a major threat to patients admitted to hospitals and infection rates following orthopedic arthroplasty surgery are as high as 4%. A 405-nm high-intensity narrow spectrum light has been proven to reduce environmental contamination in hospital isolation rooms, and there is potential to develop this technology for application in arthroplasty surgery. Cultured rat osteoblasts were exposed to varying light intensities and it was found that exposures of up to a dose of 36 J/cm2 had no significant effect on cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay], function (alkaline phosphatase activity), and proliferation rate (BrdU cell proliferation assay). High irradiance exposures (54 J/cm2) significantly affected the cell viability indicating that the effects of 405-nm light on osteoblasts are dose dependent. Additionally, exposure of a variety of clinically related bacteria to a dose of 36 J/cm2 resulted in up to 100% kill. These results demonstrating the differential sensitivity of osteoblasts and bacteria to 405-nm light are an essential step toward developing the technique for decontamination in orthopedic surgery.

Multiple tendon ruptures of unknown etiology

Tendon ruptures are common findings in foot and ankle practice. The etiology of tendon ruptures tends to be multifactorial-usually due to a combination of trauma, effects of systemic diseases, adverse effects of medications, and obesity. We present an unusual case of right Achilles tendinitis, left Achilles tendon rupture, bilateral peroneus longus tendon rupture, and left peroneus brevis tendon rupture of unknown etiology. This case report highlights the need for research for other possible, lesser known etiologies of tendon pathology.

LEVEL OF EVIDENCE

Therapeutic, Level IV, Case Study.

Continuous decontamination of an intensive care isolation room during patient occupancy using 405 nm light technology

Environmental contamination within intensive care units (ICU) is recognised as a source of patient infection, and improved cleaning and disinfection methods are continually being sought. Visible light of 405 nm has been shown to have bactericidal properties, and this communication reports on the use of a ceiling-mounted 405 nm light system for continuous environmental disinfection of contact surfaces and air in an occupied ICU isolation room. Levels of bacterial contamination on a range of contact surfaces around the room were assessed before, during and after use of the system. For each study, the lighting units were operated continuously during daylight hours. Results demonstrate that the spatial distribution of bacterial contamination was reduced almost uniformly across all sampled contact surfaces during use of the 405 nm light system. Pooled data showed that significant reductions in overall bacterial contamination around the room were achieved, with bacterial counts reduced by up to 67% ( p=0.0001) over and above that achieved with standard cleaning and infection control procedures alone. Use of 405 nm light significantly reduced environmental contamination across almost all sampled contact surfaces within the ICU isolation room. This has particular benefit in ICU where equipment and other ‘hand-touch’ sites make routine cleaning difficult, thus helping maintain a cleaner environment, and contributing to reducing cross-infection from environmental sources.

A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere

We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT∕LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT∕LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-α hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-α, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons, in which differences of 1.5-2 ppmv were routinely observed, and demonstrates that the accuracy of HHH is consistent with other instruments which use a range of detection methods and sampling techniques.

Photoinactivation of bacteria attached to glass and acrylic surfaces by 405 nm light: potential application for biofilm decontamination

Attachment of bacteria to surfaces and subsequent biofilm formation remains a major cause of cross-contamination capable of inducing both food-related illness and nosocomial infections. Resistance to many current disinfection technologies means facilitating their removal is often difficult. The aim of this study was to investigate the efficacy of 405 nm light for inactivation of bacterial attached as biofilms to glass and acrylic. Escherichia coli biofilms (10(3)-10(8) CFU mL(-1)) were generated on glass and acrylic surfaces and exposed for increasing times to 405 nm light (5-60 min) at ca 140 mW cm(-2). Successful inactivation of biofilms has been demonstrated, with results highlighting complete/near-complete inactivation (up to 5 log10 reduction on acrylic and 7 log10 on glass). Results also highlight that inactivation of bacterial biofilms could be achieved whether the biofilm was on the upper "directly exposed" surface or "indirectly exposed" underside surface. Statistically significant inactivation was also shown with a range of other microorganisms associated with biofilm formation (Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes). Results from this study have demonstrated significant inactivation of bacteria ranging from monolayers to densely populated biofilms using 405 nm light, highlighting that with further development this technology may have potential applications for biofilm decontamination in food and clinical settings.

Gastrocnemius recession for chronic noninsertional Achilles tendinopathy

BACKGROUND

In patients with chronic Achilles tendinopathy, several operative techniques have been described for treatment. A case report has shown that gastrocnemius recession as treatment can normalize MRI findings and relieve clinical symptoms consistent with chronic Achilles tendinopathy. The purpose of this study was to present the results of the treatment of chronic Achilles tendinopathy with gastrocnemius recession.

METHODS

Of 12 patients, 8 (7 females, 1 male) who underwent gastrocnemius recession for refractory Achilles tendinopathy between July 2004 and January 2009 were available for follow-up. All patients filled out a SF-36 health survey, a foot function index, an AOFAS ankle and hindfoot scale, and a simple survey formulated by our group of investigators. Of the 8 patients, 7 were available to return for clinical assessment. Patients had an average age of 49.9 years (SD = 11.6) at the time of surgery and average time of follow-up was 34.6 months (SD = 18.1).

RESULTS

The mean pain score (VAS 0-10 scale) significantly decreased from 7.3 (SD = 1.7) preoperatively to 1 (SD = 1.8) postoperatively at the time of follow-up (P < .001). The mean AOFAS ankle and hindfoot score was 94.4 (SD = 9.8), which was significantly improved when compared with previously published scores for patients who underwent Achilles debridement with FHL transfer (P = .007). All 8 categories on the SF-36 health survey showed no significant difference with published data for US population values and previously published data for patients who underwent FHL transfer.

CONCLUSION

Gastrocnemius recession for the treatment of refractory Achilles tendinopathy was a viable treatment option following the failure of nonoperative management. All 8 of our patients had excellent pain relief, good clinical outcome, and were satisfied at the time of follow-up.

405 nm Light exposure of osteoblasts and inactivation of bacterial isolates from arthroplasty patients: potential for new disinfection applications?

Infection rates after arthroplasty surgery are between 1-4 %, rising significantly after revision procedures. To reduce the associated costs of treating these infections, and the patients' post-operative discomfort and trauma, a new preventative method is required. High intensity narrow spectrum (HINS) 405 nm light has bactericidal effects on a wide range of medically important bacteria, and it reduced bacterial bioburden when used as an environmental disinfection method in a Medical Burns Unit. To prove its safety for use for environmental disinfection in orthopaedic theatres during surgery, cultured osteoblasts were exposed to HINS-light of intensities up to 15 mW/cm2 for 1 h (54 J/cm2). Intensities of up to 5 mW/cm2 for 1 h had no effect on cell morphology, activity of alkaline phosphatase, synthesis of collagen or osteocalcin expression, demonstrating that under these conditions this dose is the maximum safe exposure for osteoblasts; after exposure to 15 mW/cm2 all parameters of osteoblast function were significantly decreased. Viability (measured by protein content and Crystal Violet staining) of the osteoblasts was not influenced by exposure to 5 mW/cm2 for at least 2 h. At 5 mW/cm2 HINS-light is an effective bactericide. It killed 98.1 % of Staphylococcus aureus and 83.2 % Staphylococcus epidermis populations seeded on agar surfaces, and is active against both laboratory strains and clinical isolates from infected hip and knee arthroplasties. HINS-light could have potential for development as a method of disinfection to reduce transmission of bacteria during arthroplasty, with wider applications in diverse surgical procedures involving implantation of a medical device.