Predictors of Mortality and Revision Following Digital Amputation for Infection and Necrosis.

PURPOSE: Digital amputation is a commonly performed procedure for infection and necrosis in patients with diabetes, peripheral vascular disease (PVD), and on dialysis. There is a lack of data regarding prognosis for revision amputation and mortality following digital amputation in these patients. METHODS: All digital amputations over 10-year period (2008-2018) at a single center were reviewed. There were 484 amputations in 360 patients, among which 358 were performed for trauma (reference sample) and 126 for infection or necrosis (sample of interest). Patient death and revision were determined from National Vital Statistics System and medical records. Propensity score matching was performed to compare groups. Data were then compared to the Social Security Administration Actuarial Life Table for 2015 to determine age-matched expected mortality. RESULTS: The 2-year revision rate was 34% for amputations performed for infection or necrosis, compared to 15% for amputations due to trauma. For amputations performed for infection or necrosis, the revision rate was 47.7% when diabetes, PVD, and dialysis were present. Among all patients with infection or necrosis (n = 104) undergoing a digital amputation, overall survival at 2, 5, and 10 years was 79.4%, 57.3%, and 17.5%, respectively, which represented a 3.2-fold increased risk of death compared to controls. (hazard ratio, 3.19; 95% confidence interval, 1.47-6.93). For amputations due to trauma, mortality was no different from that in the age-matched general population. CONCLUSIONS: Mortality and revision risk are high for patients requiring a digital amputation for infection or necrosis and are further increased with medical comorbidities. Hand surgeons should consider the prognostic implications of these data when counseling patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Does the Lauge-Hansen Injury Mechanism Predict Posterior Malleolar Fracture Morphology?

The Lauge-Hansen ankle fracture classification system is widely accepted and is utilized to describe and predict ankle fracture patterns based on the mechanism of injury. Multiple studies have shown inconsistencies in the Lauge-Hansen's ability to predict fracture patterns based on the mechanism of injury. We set out to determine if the posterior malleolar fracture pattern is associated with the fracture types described by Lauge-Hansen. In this retrospective cohort study, we reviewed 153 patients with trimalleolar ankle fractures as diagnosed using computed tomography scans. Timing of injury was from February 2013 to August 2017. Patient ages ranged between 18 and 89 years old. Each patient had a complete clinical and radiographic workup including a preoperative computed tomographic scan following initial fracture reduction in the emergency room. We classified each ankle fracture based on plain film radiographs using the Lauge-Hansen classification scheme. Each individual posterior malleolar fracture was evaluated on computed tomography imaging and described using both the Haraguchi and Bartonicek-Rammelt classification systems. Of the 153 patients identified with trimalleolar ankle fractures, 70% were female (±20%), the mean age was 51 y (±8 y), and the mean body mass index was 30 kg/m2 (±3 kg/m2). We did not observe a significant association between the Lauge-Hansen injury mechanism and either the Bartonicek-Rammelt or the Haraguchi trimalleolar ankle fracture classification systems (chi-square correlation tests p > .05).

An ultrashort video can teach residents to perform a fingertip injury repair.

BACKGROUND: Acute fingertip injuries are common. Providers in rural and underserved areas often transfer these patients due to lack of comfort and skill with treating these injuries. Current learners prefer short and high-density educational material. It is unknown if basic hand procedures can be taught using ultrashort training videos. This study investigates whether fingertip repair can be taught using a 60-second educational video viewed immediately prior to performing the procedure. METHODS: A standardized cadaveric fingertip injury model was developed. Twenty-three emergency medicine residents each having minimal experience with fingertip injury repair were randomized into one of three study arms: A) no video, B) standard-length (8-minute) video, and C) ultrashort (60-second) video. Each subject was presented with an injured cadaveric finger and asked to prepare for and perform the repair within a 30-minute time frame. The repair was graded on a 10-point scale following a standard rubric. Time to completion, preparedness, and subjects' confidence were also assessed. Results were analyzed by one-way ANOVA and Kruskal-Wallis tests. RESULTS: Mean repair scores for the standard-length video group (9.5 ± 0.3) and the ultrashort video group (9.2 ± 0.3) were significantly higher than those of the no video group (4.0 ± 0.3, p < 0.05 for both comparisons). Mean time to completion of the exercise was significantly shorter in the ultrashort video group (19 ± 2 minutes) than in the standard-length video group (26 ± 2 minutes). Subject-reported outcomes (median preparedness, median post-repair confidence, and median change in confidence following the procedure) were all significantly higher in the standard-length video group and the ultrashort video group than in the no video group (p < 0.05 for all comparisons). CONCLUSION: A 60-second educational video viewed immediately prior to performing a fingertip injury repair can effectively teach an emergency medicine resident to correctly perform the procedure.

Neonatal Forearm Compartment Syndrome Secondary to Intrauterine Brachiocephalic Arterial Thrombosis: A Case Report.

CASE: A newborn presented with necrotic skin lesions and contractures of the right upper extremity. Ultrasonography indicated the presence of a brachiocephalic artery thrombosis, and clinical examination demonstrated a neonatal forearm compartment syndrome. Surgical treatment included decompressive fasciotomy of the right forearm. The right-sided brachiocephalic thrombosis resulted in left hemiplegic cerebral palsy. At the 3-year follow-up, the patient had near-normal function of the right upper extremity. This case has detailed preoperative video and follow-up to illustrate this rare but modifiable condition. CONCLUSION: This case demonstrates a unique cause of neonatal forearm compartment syndrome (brachiocephalic arterial thrombosis) and the results of prompt surgical treatment.

Modeled Wide-Awake, Local-Anesthetic, No-Tourniquet Surgical Procedures Do Not Impair Driving Fitness: An Experimental On-Road Noninferiority Study.

BACKGROUND: The use of wide-awake, local-anesthetic, no-tourniquet (WALANT) surgical techniques is increasingly common, and patients commonly ask whether they may drive home following these procedures. The impact of a numb hand and bulky dressing on driving fitness is unknown, and there is no literature to guide surgeons when counseling these patients. Thus, the primary objective of the present study was to determine driving fitness following a modeled-WALANT procedure. METHODS: Twelve right-handed individuals (6 male and 6 female) with an average age of 50 years (range, 38 to 64 years) were enrolled. An instrumented vehicle was used to obtain driving kinematic and behavioral data, thus allowing for a multidimensional assessment of driving fitness. Participants first performed a drive to establish baseline kinematic metrics. The route included both public streets and a closed course. Several driving tasks were assessed, including reverse parking, parallel parking, and perpendicular parking. The total course length was 18 miles (29 kilometers) and took 45 to 55 minutes to complete. After the first drive, 10 mL of 1% lidocaine was injected in the volar aspect of the right wrist and another 10 mL was injected into the right carpal tunnel to model the anesthetic used for a WALANT carpal tunnel release, and a bulky soft dressing was applied. The modeled-WALANT drive included an identical route and tasks, in addition to a surprise event to evaluate emergency responsiveness. Driving metrics were analyzed for noninferiority of the modeled-WALANT state to baseline driving. RESULTS: The modeled-WALANT state showed noninferiority to baseline driving on all 11 analyzed dimensions of driving behavior compared with the control drives. In the modeled-WALANT state, participants drove more conservatively, braked harder, and steered more smoothly. All participants safely performed the 3 parking tasks and emergency response maneuver. Driving fitness in the modeled-WALANT state was noninferior to driving fitness in the preoperative drive. CONCLUSIONS: A modeled-WALANT state has no clinically relevant negative impact on driving fitness, and thus surgeons should not discourage patients from driving home after unilateral WALANT surgical hand procedures. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Kinetics and Thermodynamics of Killing a Quantum Dot.

Light-emitting nanocrystal quantum dots (QDs) are of high interest for use as down-conversion phosphors and direct emission sources in bulk solid-state devices and as reliable sources of single photons in quantum information science. However, these materials are prone to photooxidation that reduces the emission quantum yield over time. Current commercial applications use device architectures to prevent oxidation without addressing the underlying degradation reactions at the nanocrystal level. To instead prevent loss of functionality by better synthetic engineering of the nanoscale emitters themselves, the underlying properties of these reactions must be understood and readily accessible. Here, we use solid-state spectroscopy to obtain kinetic and thermodynamic parameters of photothermal degradation in single QDs by systematically varying the ambient temperature and photon pump fluence. We describe the resulting degradation in emission with a modified form of the Arrhenius equation and show that this reaction proceeds via pseudo-zero-order reaction kinetics by a surface-assisted process with an activation energy of 60 kJ/mol. We note that the rate of degradation is ∼12 orders of magnitude slower than the rate of excitonic processes, indicating that the reaction rate is not determined by electron or hole trapping. In the search for new robust light-emitting nanocrystals, the reported analysis method will enable direct comparisons between differently engineered nanomaterials.

Role of shell composition and morphology in achieving single-emitter photostability for green-emitting "giant" quantum dots.

The use of the varied chemical reactivity of precursors to drive the production of a desired nanocrystal architecture has become a common method to grow thick-shell graded alloy quantum dots (QDs) with robust optical properties. Conclusions on their behavior assume the ideal chemical gradation and uniform particle composition. Here, advanced analytical electron microscopy (high-resolution scanning transmission electron microscopy coupled with energy dispersive spectroscopy) is used to confirm the nature and extent of compositional gradation and these data are compared with performance behavior obtained from single-nanocrystal spectroscopy to elucidate structure, chemical-composition, and optical-property correlations. Specifically, the evolution of the chemical structure and single-nanocrystal luminescence was determined for a time-series of graded-alloy "CdZnSSe/ZnS" core/shell QDs prepared in a single-pot reaction. In a separate step, thick (∼6 monolayers) to giant (>14 monolayers) shells of ZnS were added to the alloyed QDs via a successive ionic layer adsorption and reaction (SILAR) process, and the impact of this shell on the optical performance was also assessed. By determining the degree of alloying for each component element on a per-particle basis, we observe that the actual product from the single-pot reaction is less "graded" in Cd and more so in Se than anticipated, with Se extending throughout the structure. The latter suggests much slower Se reaction kinetics than expected or an ability of Se to diffuse away from the initially nucleated core. It was also found that the subsequent growth of thick phase-pure ZnS shells by the SILAR method was required to significantly reduce blinking and photobleaching. However, correlated single-nanocrystal optical characterization and electron microscopy further revealed that these beneficial properties are only achieved if the thick ZnS shell is complete and without large lattice discontinuities. In this way, we identify the necessary structural design features that are required for ideal light emission properties in these green-visible emitting QDs.

Intraneural Peroneal Ganglion Cyst Excision in a Pediatric Patient: A Case Report.

CASE: A 14-year-old female presented with a profound foot drop after trauma to the right leg. Clinical examination and electrodiagnostic studies demonstrated a dense palsy of the common peroneal nerve. Magnetic resonance imaging revealed an intraneural peroneal ganglion cyst at the fibular neck. Surgical treatment included decompression and transection of the articular branch to the proximal tibiofibular joint. At the 1-year follow-up, the patient demonstrated complete recovery of peroneal nerve function. CONCLUSIONS: This case demonstrates a rare finding of a pediatric intraneural peroneal ganglion cyst. The presentation and treatment is well-documented and adds depth to the literature on a sparsely reported condition.

Identification of Microsurgical Suture Needles in the Hand Using Plain Radiographs.

Our objective is to determine if radiographs are adequate for identification of retained microsurgical needles. Four microsurgical needles ranging from 3.8 mm to 6.5 mm in length and 50 µ to 130 µ in diameter were affixed to an anthropomorphic phantom limb. Portable radiograph images were then obtained and viewed by a group of 20 subjects comprised of attending radiologists, attending orthopaedic surgeons, orthopaedic surgery residents and operating room nurses. For all subjects, 3.35 out of 4 needles were identified in a mean 4.7 minutes. Radiologists identified all four needles and needed the least amount of time (mean 2.3 minutes). Orthopaedic surgery attendings identified a mean 3.5 of 4 needles while orthopaedic surgery residents and operating room nurses identified a mean 3 of 4 needles. Identification of microsurgical needles is possible using digital radiographs but requires 2-5 minutes of searching the image and adjusting the windows. (Journal of Surgical Orthopaedic Advances 29(4):230-233, 2020).

New Long-Term Opioid Prescription-Filling Behavior Arising in the 15 Months After Orthopaedic Surgery.

BACKGROUND: The opioid crisis is a well-known public health issue. The risk of new long-term opioid prescription-filling behavior has been investigated after certain spinal procedures and total knee and hip arthroplasty. However, this has not been examined after many other common orthopaedic procedures. The purpose of this study was to determine the rates of long-term opioid prescription-filling behavior after common orthopaedic surgical procedures in patients who were not taking opioids preoperatively. METHODS: This study utilized the Virginia All-Payer Claims Database (APCD), an insurance claims database with data from 3.7 to 4 million patients per year. Patients who underwent orthopaedic procedures and who had not filled an opioid prescription in the time period from 2 weeks to 1 year preceding the surgical procedure were selected for evaluation in our study. The percentage of these patients who then filled at least 10 prescriptions or a 120-day supply of opioids in the time period from 90 to 455 days following the surgical procedure was calculated for the 50 most commonly billed orthopaedic surgical procedures. RESULTS: The rate of long-term opioid prescription-filling behavior in patients who were not taking opioids preoperatively for the 50 most common orthopaedic procedures was 5.3% (95% confidence interval, 5.1% to 5.5%). The highest rates were observed after spinal procedures. The lowest rates were seen after anterior cruciate ligament (ACL) reconstruction. Revision surgical procedures were found to have a significantly higher rate than primary procedures (p < 0.05). The rate was also related to increasing case complexity. CONCLUSIONS: New long-term opioid prescription-filling behavior is common after orthopaedic surgical procedures in patients who were not taking opioids preoperatively. Risk factors include spine surgery, revision surgery, and cases with increased complexity. Orthopaedic surgeons need to be aware of this risk. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Photophysics of Thermally-Assisted Photobleaching in "Giant" Quantum Dots Revealed in Single Nanocrystals.

Quantum dots (QDs) are steadily being implemented as down-conversion phosphors in market-ready display products to enhance color rendering, brightness, and energy efficiency. However, for adequate longevity, QDs must be encased in a protective barrier that separates them from ambient oxygen and humidity, and device architectures are designed to avoid significant heating of the QDs as well as direct contact between the QDs and the excitation source. In order to increase the utility of QDs in display technologies and to extend their usefulness to more demanding applications as, for example, alternative phosphors for solid-state lighting (SSL), QDs must retain their photoluminescence emission properties over extended periods of time under conditions of high temperature and high light flux. Doing so would simplify the fabrication costs for QD display technologies and enable QDs to be used as down-conversion materials in light-emitting diodes for SSL, where direct-on-chip configurations expose the emitters to temperatures approaching 100 °C and to photon fluxes from 0.1 W/mm2 to potentially 10 W/mm2. Here, we investigate the photobleaching processes of single QDs exposed to controlled temperature and photon flux. In particular, we investigate two types of room-temperature-stable core/thick-shell QDs, known as "giant" QDs for which shell growth is conducted using either a standard layer-by-layer technique or by a continuous injection method. We determine the mechanistic pathways responsible for thermally-assisted photodegradation, distinguishing effects of hot-carrier trapping and QD charging. The findings presented here will assist in the further development of advanced QD heterostructures for maximum device lifetime stability.

Using shape to turn off blinking for two-colour multiexciton emission in CdSe/CdS tetrapods.

Semiconductor nanostructures capable of emitting from two excited states and thereby of producing two photoluminescence colours are of fundamental and potential technological significance. In this limited class of nanocrystals, CdSe/CdS core/arm tetrapods exhibit the unusual trait of two-colour (red and green) multiexcitonic emission, with green emission from the CdS arms emerging only at high excitation fluences. Here we show that by synthetic shape-tuning, both this multi-colour emission process, and blinking and photobleaching behaviours of single tetrapods can be controlled. Specifically, we find that the properties of dual emission and single-nanostructure photostability depend on different structural parameters-arm length and arm diameter, respectively-but that both properties can be realized in the same nanostructure. Furthermore, based on results of correlated photoluminescence and transient absorption measurements, we conclude that hole-trap filling in the arms and partial state-filling in the core are necessary preconditions for the observation of multiexciton multi-colour emission.

Design of a Hole Trapping Ligand.

A new ligand that covalently attaches to the surface of colloidal CdSe/CdS nanorods and can simultaneously chelate a molecular metal center is described. The dithiocarbamate-bipyridine ligand system facilitates hole transfer through energetic overlap at the inorganic-organic interface and conjugation through the organic ligand to a chelated metal center. Density functional theory calculations show that the coordination of the free ligand to a CdS surface causes the formation of two hybridized molecular states that lie in the band gap of CdS. The further chelation of Fe(II) to the bipyridine moiety causes the presence of seven midgap states. Hole transfer from the CdS valence band to the midgap states is dipole allowed and occurs at a faster rate than what is experimentally known for the CdSe/CdS band-edge radiative recombination. In the case of the ligand bound with iron, a two-step process emerges that places the hole on the iron, again at rates much faster than band gap recombination. The system was experimentally assembled and characterized via UV-vis absorbance spectroscopy, fluorescence spectroscopy, time-resolved photoluminescence spectroscopy, and energy dispersive X-ray spectroscopy. Theoretically predicted red shifts in absorbance were observed experimentally, as well as the expected quench in photoluminescence and lifetimes in time-resolved photoluminescence.

Quantum Yield Heterogeneity among Single Nonblinking Quantum Dots Revealed by Atomic Structure-Quantum Optics Correlation.

Physical variations in colloidal nanostructures give rise to heterogeneity in expressed optical behavior. This correlation between nanoscale structure and function demands interrogation of both atomic structure and photophysics at the level of single nanostructures to be fully understood. Herein, by conducting detailed analyses of fine atomic structure, chemical composition, and time-resolved single-photon photoluminescence data for the same individual nanocrystals, we reveal inhomogeneity in the quantum yields of single nonblinking "giant" CdSe/CdS core/shell quantum dots (g-QDs). We find that each g-QD possesses distinctive single exciton and biexciton quantum yields that result mainly from variations in the degree of charging, rather than from volume or structure inhomogeneity. We further establish that there is a very limited nonemissive "dark" fraction (<2%) among the studied g-QDs and present direct evidence that the g-QD core must lack inorganic passivation for the g-QD to be "dark". Therefore, in contrast to conventional QDs, ensemble photoluminescence quantum yield is principally defined by charging processes rather than the existence of dark g-QDs.

Electrical Control of near-Field Energy Transfer between Quantum Dots and Two-Dimensional Semiconductors.

We investigate near-field energy transfer between chemically synthesized quantum dots (QDs) and two-dimensional semiconductors. We fabricate devices in which electrostatically gated semiconducting monolayer molybdenum disulfide (MoS2) is placed atop a homogeneous self-assembled layer of core-shell CdSSe QDs. We demonstrate efficient nonradiative Förster resonant energy transfer (FRET) from QDs into MoS2 and prove that modest gate-induced variation in the excitonic absorption of MoS2 leads to large (∼500%) changes in the FRET rate. This in turn allows for up to ∼75% electrical modulation of QD photoluminescence intensity. The hybrid QD/MoS2 devices operate within a small voltage range, allow for continuous modification of the QD photoluminescence intensity, and can be used for selective tuning of QDs emitting in the visible-IR range.

Correlation of atomic structure and photoluminescence of the same quantum dot: pinpointing surface and internal defects that inhibit photoluminescence.

In a size regime where every atom counts, rational design and synthesis of optimal nanostructures demands direct interrogation of the effects of structural divergence of individuals on the ensemble-averaged property. To this end, we have explored the structure-function relationship of single quantum dots (QDs) via precise observation of the impact of atomic arrangement on QD fluorescence. Utilizing wide-field fluorescence microscopy and atomic number contrast scanning transmission electron microscopy (Z-STEM), we have achieved correlation of photoluminescence (PL) data and atomic-level structural information from individual colloidal QDs. This investigation of CdSe/CdS core/shell QDs has enabled exploration of the fine structural factors necessary to control QD PL. Additionally, we have identified specific morphological and structural anomalies, in the form of internal and surface defects, that consistently vitiate QD PL.

Elimination of hole-surface overlap in graded CdS(x)Se(1-x) nanocrystals revealed by ultrafast fluorescence upconversion spectroscopy.

Interaction of charge carriers with the surface of semiconductor nanocrystals plays an integral role in determining the ultimate fate of the excited state. The surface contains a dynamic ensemble of trap states that can localize excited charges, preventing radiative recombination and reducing fluorescence quantum yields. Here we report quasi-type-II band alignment in graded alloy CdSxSe1-x nanocrystals revealed by femtosecond fluorescence upconversion spectroscopy. Graded alloy CdS(x)Se(1-x) quantum dots are a compositionally inhomogeneous nano-heterostructure designed to decouple the exciton from the nanocrystal surface. The large valence band offset between the CdSe-rich core and CdS-rich shell separates the excited hole from the surface by confining it to the core of the nanocrystal. The small conduction band offset, however, allows the electron to delocalize throughout the entire nanocrystal and maintain overlap with the surface. Indeed, the ultrafast charge carrier dynamics reveal that the fast 1-3 ps hole-trapping process is fully eliminated with increasing sulfur composition and the decay constant for electron trapping (∼ 20-25 ps) shows a slight increase. These findings demonstrate progress toward highly efficient nanocrystal fluorophores that are independent of their surface chemistry to ultimately enable their incorporation into a diverse range of applications without experiencing adverse effects arising from dissimilar environments.