Education Research in Orthopaedic Surgery

With the ever-changing dynamics of surgical training, it is essential for the content of educational research to evolve simultaneously. This study aimed to assess the current state of scholarly work in orthopaedic training education and to identify particular educational topics that are trending in the literature.

Assessment of Spin in the Abstracts of Systematic Reviews and Meta-analyses on Platelet-Rich Plasma Treatment in Orthopaedics: A Cross-sectional Analysis

Background

Systematic reviews on the use of platelet-rich plasma (PRP) in orthopaedic surgery are abundant in current published literature. However, a beautification of results (referred to as spin) has been noted in abstracts across various aspects of medicine.

Purpose

To determine the prevalence of spin in systematic reviews of PRP-related orthopaedic surgery abstracts.

Study Design

Cross-sectional study.

Methods

Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and Murad and Wang guidelines, we conducted a search in Medline, Embase, and the Cochrane Database for reviews on PRP-related orthopaedic surgery. The search included studies published from inception until June 30, 2021. Included were systematic reviews written in English that involved the use of PRP in the treatment of orthopaedic injuries in human participants. The abstracts of the included reviews were evaluated for the top 9 types of spin as described by Yavchitz et al in 2016. We determined the relationship between spin and study characteristics using odds ratios.

Results

Of an initial 1560 studies, 176 were included. We found that 50 studies (28.4%) contained at least 1 form of spin. The 2 most common forms of spin found in our sample were type 5 ("Conclusion claims the beneficial effect of treatment despite high risk of bias"; n = 27 [15.3%]) and type 3 ("Selective reporting or overemphasis of efficacy in outcomes favoring beneficial effect of intervention"; n = 18 [10.2%]). No statistical significance was found between study characteristics and the presence of spin.

Conclusion

Spin was present in 28% of the systematic reviews that covered PRP-related orthopaedic treatments. Spin was not associated with general study characteristics, including adherence to PRISMA guidelines or funding. Journals and authors should be aware of spin in articles and avoid its usage.

Increased Bite Distance From the Edge Lowers Risk of Pullout of Simple Sutures from Acellular Dermal Allograft

Purpose

To investigate whether pullout strength in the acellular dermal allograft matrix (ADM) used for superior capsule reconstruction depends on the distance from the edge of the graft.

Methods

ADM used for superior capsule reconstruction was obtained and cut into 30 squares. Two sutures were placed through the center of each graft by using a loaded Keith needle and forming a simple stitch. The grafts were divided into 3 groups of 10 grafts with a distance of 5 mm, 10 mm or 15 mm from the closest edge of the graft, respectively. The grafts were then preloaded to 5 N and pulled to failure at a rate of 12 mm/s on an MTS 858 MiniBionix servohydraulic mechanical test frame. The load to failure was recorded as well as the stiffness of each graft.

Results

The mean load to failure was 34.5 N (SD 7.89) for the 5 mm grafts, 31.7 N (SD 5.99) for the 10 mm grafts, and 66.2 N (SD 18.4) for the 15 mm grafts. There was a significant difference (< 0.0001) between the large grafts (15 mm) and the 2 smaller grafts (10 mm, 5 mm). There was no significant difference in stiffness between the groups of graft (P 0.40).

Conclusion

Placing the suture at least 15 mm from the edge of the graft increases the graft's ultimate yield strength to suture pullout.

Clinical Relevance

The depths of the suture in ADM could improve pullout strength for constructs of superior capsular reconstructions.

QSAR of the Anticonvulsant Enaminones; Molecular Modeling Aspects and other Assessments

The enaminones represent potentially useful agents for the clinical treatment in generalized tonic-clonic seizures (Epilepsia, 1993, 34(6), 1141-1145, Biopharm. Drug Disp. 2003, 397-407). A regression analysis was performed to provide a quantitative structure-activity relationship (QSAR) correlation model for prediction of activity for the anticonvulsant enaminones. Molecular modeling was performed to determine the molecular confluence of the Unverferth model (J. Med. Chem. 1998, 41, 63-73) to the enaminones. Conclusions related to the sodium channel model were assessed.

Use of a kinetic energy orifice as a probe of metastable dissociation in Fourier transform ion cyclotron resonance mass spectrometry

Although Fourier transform ion cyclotron resonance mass spectrometry is a powerful tool in the qualitative observation of gas phase reactions, ion detection is on the millisecond time scale, orders of magnitude longer than typically found when using a sector instrument. Observations of short-lived species such as chemically activated adduct ions can be accomplished using selective ion excitation as a probe of intermediate lifetime. Whereas ion elimination has been shown to be effective in monitoring ion lifetimes on the microsecond time scale, problems associated with detecting ions produced with high kinetic energies limits the technique. Use of a kinetic energy orifice as an ion skimmer effectively eliminates ions near the center of the ion cell at relatively low kinetic energies. By modifying a single section cell to include a kinetic energy orifice, the lifetimes of chemically activated adduct ions have been investigated.

Safety and pharmacokinetics of amprenavir (141W94), a human immunodeficiency virus (HIV) type 1 protease inhibitor, following oral administration of single doses to HIV-infected adults

We conducted a double-blind, placebo-controlled, parallel, dose-escalation trial to evaluate the pharmacokinetics and safety of single, oral doses of amprenavir (141W94; formerly VX-478), a potent inhibitor of human immunodeficiency virus (HIV) type 1 protease, administered as hard gelatin capsules in 12 HIV-infected subjects. The doses of amprenavir evaluated were 150, 300, 600, 900, and 1,200 mg. Amprenavir was rapidly absorbed, with the time to maximum concentration occurring within 1 to 2 h after dosing. On the basis of power model analysis, the increase in the maximum concentration of amprenavir in plasma (Cmax) was less than dose proportional, and the increase in the area under the concentration-time curve from time zero to infinity (AUC0-infinity) was greater than dose proportional; mean slopes (with 90% confidence intervals) were 1.25 (1.16 to 1.35) and 0.78 (0.78 to 0.86) for AUC0-infinity and Cmax, respectively. Amprenavir was eliminated slowly, with a terminal-phase half-life of 8 h. A second study was conducted to determine the bioavailability of the hard gelatin capsule relative to that of a subsequently developed soft gelatin capsule. The capsules were bioequivalent in terms of AUC0-infinity but not in terms of Cmax; geometric-least-squares means ratios (with 90% confidence intervals) were 1.03 (0.92 to 1.14) and 1.25 (1.03 to 1. 53) for AUC0-infinity and Cmax, respectively. Administration of soft gelatin capsules of amprenavir with a high-fat breakfast resulted in a 14% decrease in the mean AUC0-infinity (from 9.58 to 8.26 microg. h/ml), which is not likely to be clinically significant. The most common adverse events related to amprenavir were headache, nausea, and hypesthesia. Amprenavir appears to be safe and well tolerated over the dose range of 150 to 1200 mg. On the basis of the present single-dose studies, amprenavir is an HIV protease inhibitor with favorable absorption and clearance pharmacokinetics that are only minimally affected by administration with food.

Evaluation of the effect of low-level 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure on cell mediated immunity

The immunotoxicity of TCDD in the mouse has been well documented. To date, the most sensitive endpoint to TCDD-induced toxicity in mice is that reported by Clark et al. (Clark, D. A., Gauldie, J., Szewczuk M. R. and Sweeney, G. (1981) Proc. Soc. Exper. Biol. Med. 168, 290.) who found that TCDD suppressed the murine cytotoxic T lymphocyte (CTL) response following four weekly doses of 4 ng TCDD/kg/week. However, these results have never been corroborated, as other laboratories have been unable to detect immunosuppression by TCDD at such low levels. In this study, we evaluated the effect of TCDD on the in vivo- and in vitro-generated CTL response to P815 mastocytoma cells in adult C57BL/6J female mice via a 51Cr release assay. Mice were given weekly intraperitoneal injections of TCDD or vehicle for 4 weeks at dosages ranging from 0.01 to 3.00 micrograms/kg/week. No statistically significant suppression of the in vivo- or in vitro-generated CTL response was detected at any dosage. As expected, significant increases in liver weights and decreases in thymus weights were observed at TCDD dosages of 1.0 and 3.0 micrograms/kg/week. Likewise, suppression of the antibody plaque-forming cell response to sheep erythrocytes was observed at dosages of 1.0 and 3.0 micrograms TCDD/kg/week. Although expected humoral immunosuppression and organ effects were observed, our data do not support suppression of murine CTL responses at the TCDD doses employed in this study.

Phase synchronization of an ion ensemble by frequency sweep excitation in Fourier transform ion cyclotron resonance

The Fourier transform ion cyclotron resonance (FT-ICR) signal is produced by the coherent motion of a population of ions. The ability to produce a well-defined ion packet by excitation of an initially random ion ensemble is a major limiting factor of high mass FT-ICR. Ions must be both resonant and in phase with the applied radio frequency excitation field to be accelerated to radii suitable for detection by FT-ICR. Synchronization of the phase angles of an ensemble of ions occurs by off-resonant acceleration during frequency swept excitation. Results from computer-simulated ion trajectories suggest that phase synchronization of the ion packet prior to resonant excitation results in better spatial definition of the ion ensemble.

Ion detection by Fourier transform ion cyclotron resonance: the effect of initial radial velocity on the coherent ion packet

Ion detection by Fourier transform ion cyclotron resonance (FT-ICR) is accomplished by observing a coherent ion packet produced from an initially random ensemble of ions. The coherent packet is formed by excitation with a resonant oscillating electric field. Ions that are out of phase with the applied radio frequency (rf) electric field experience a continuous misalignment of the electric field vector. The misalignment creates a net force of the electric field perpendicular to ion motion. The perpendicular component of the rf electric field creates a frequency shift resulting in phase synchronization of the ion ensemble. The phase coherence of the ion packet affects both the sensitivity and the resolution of FT-ICR.

Measurement of positional isotope exchange rates in enzyme-catalyzed reactions by fast atom bombardment mass spectrometry: application to argininosuccinate synthetase

Fast atom bombardment mass spectrometry (FAB-MS) has been used to measure positional isotope exchange rates in enzyme-catalyzed reactions. The technique has been applied to the reactions catalyzed by acetyl-CoA synthetase and argininosuccinate synthetase. The FAB technique is also able to quantitatively determine the oxygen-18 or oxygen-17 content of nucleotides on as little as 10 nmol of material with no prior derivatization. Acetyl-CoA synthetase has been shown by FAB-MS to catalyze the positional exchange of an oxygen-18 of ATP from the beta-nonbridge position to the alpha beta-bridge position in the presence of acetate. These results are consistent with acetyl adenylate as a reactive intermediate in this reaction. Argininosuccinate synthetase was shown not to catalyze a positional isotope exchange reaction designed to test for the formation of citrulline adenylate as a reactive intermediate. Argininosuccinate synthetase was also found not to catalyze the transfer of oxygen-18 from [ureido-18O]citrulline to the alpha-phosphorus of ATP in the absence of added aspartate. This experiment was designed to test for the transient formation of carbodiimide as a reactive intermediate. These results suggest that either argininosuccinate synthetase does not catalyze the formation of citrulline adenylate or the enzyme is able to completely suppress the rotation of the phosphoryl groups of PPi.

Pharmacokinetic evaluation of the digoxin-amiodarone interaction

Amiodarone is known to raise serum digoxin levels. This study was designed to evaluate the pharmacokinetic basis of this interaction in 10 normal subjects. The pharmacokinetic variables for digoxin were determined after a 1.0 mg intravenous dose of digoxin in each subject, before and after oral amiodarone, 400 mg daily for 3 weeks. During amiodarone administration, systemic clearance of digoxin was reduced from 234 +/- 72 ml/min (mean +/- standard deviation) to 172 +/- 33 ml/min (p less than 0.01). This was due to reductions in both renal clearance (from 105 +/- 39 to 84 +/- 15 ml/min) (p less than 0.05) and nonrenal clearance (from 130 +/- 38 to 88 +/- 20 ml/min) (p less than 0.01). Digoxin half-life of elimination was prolonged from 34 +/- 13 to 40 +/- 16 hours (p less than 0.05). Digoxin volume of distribution was not significantly changed. Amiodarone caused a three- to fivefold increase in serum reverse triiodothyronine levels, but changes in thyroid function were not quantitatively related to the changes in digoxin pharmacokinetics. These alterations in digoxin pharmacokinetics produced by amiodarone explain the increase in serum digoxin level that has been observed when this drug combination has been used clinically.

Suppression of ventricular ectopy with intravenous metoprolol in patients with chronic obstructive pulmonary disease

Intravenous metoprolol, 0.2 mg/kg, was given to 11 patients with stable, partially reversible chronic obstructive pulmonary disease (COPD) and frequent ventricular ectopic depolarizations (VEDs). The frequency of VEDs during 8 h of continuous ECG recording was reduced from a mean of 214/h to 86/h (p less than .001). Four/11 patients had a greater than 90% reduction in VEDs. There were no adverse clinical effects during the period of drug administration. However, metoprolol produced small declines of 14% in the forced expiratory volume in 1 sec (FEB1) and 21% in the forced expiratory flow rate between 25% and 75% of the forced vital capacity (FVC) (FEF25-75). These data suggest that iv metoprolol is effective in reducing the frequency of VEDs in patients with COPD, although the extent of reduction in VEDs shows considerable interindividual variation. Metoprolol can be administered iv without inducing clinical bronchospasm in most patients.

Mexiletine and quinidine in ventricular ectopy

The antidysrhythmic efficacy and tolerance of mexiletine and quinidine were compared in 26 ambulatory patients with chronic ventricular ectopy. Thirteen patients were treated with mexiletine and 13 with quinidine. The treatment groups were comparable in age and cardiac diagnoses, in frequency of untreated ventricular ectopy, in the presence of complex forms, and in previous drug failures. After two 24-hr ambulatory ECG recordings, the patients were treated according to a double-blind, dose-ranging protocol. Efficacy was defined as reduction in ventricular ectopic frequency by at least 70% in a comparison of two 24-hr ambulatory ECG recordings after drug with the two pretreatment recordings. Suppression of ventricular ectopic frequency by at least 70% was achieved in seven mexiletine-treated patients and eight quinidine-treated patients. Neither drug consistently abolished complex forms of ectopy. The incidence of adverse effects was of the same order in the two groups. We conclude that mexiletine is as effective as quinidine in the suppression of ventricular ectopy. Use of both drugs is limited by adverse effects.

Suppression of atrial ectopy with intravenous metoprolol in chronic obstructive pulmonary disease patients

To determine the efficacy of a cardioselective beta blocker in the treatment of atrial ectopy in patients with chronic obstructive pulmonary disease (COPD), we administered intravenous metoprolol (0.2 mg/kg) to six patients with atrial ectopic depolarizations (AEDs) and chronic partially reversible airflow limitation (FEV1 = 1.24 +/- 0.21 liter, mean +/- S.E.). Metoprolol reduced the mean frequency of AEDs from 713 +/- 237 per hour to 218 +/- 127 per hour. Furthermore, three of six patients experienced an 85 per cent or greater decrease in AEDs. No changes were observed in FEV1, FVC, or FEF25-75 over the course of the study. These data suggest that intravenous metoprolol is effective in reducing the frequency of AEDs and that it can be administered to patients with COPD without causing an increase in airflow limitation.

Kinetics of the digoxin-aspirin combination

Digoxin interacts kinetically with many drugs in man. These interactions may result in digoxin toxicity. Aspirin has been shown to raise serum digoxin levels in the dog. We evaluated the effect of aspirin on digoxin single-dose kinetics in eight healthy adults. Aspirin induced no change in digoxin total body clearance, volume of distribution, elimination half-life, or renal or creatinine clearance. Trough serum salicylate levels ranged from 93 to 163 microgram/ml. We conclude that no alteration is required in digoxin dosing when aspirin is used.

Fluorescent lifetimes of molecules on silver-island films

The fluorescence of molecules on silver-island films exhibits nonexponential decay and is several orders of magnitude more rapid than on a silica surface, while the total emission intensity is slightly increased. This behavior results from the electromagnetic coupling between the fluorescing molecules and the plasmon resonances of the silver islands. We obtain good agreement with a model that uses the same theory for the electromagnetic coupling as has been used to account for surface-enhanced Raman scattering.

Effect of antidysrhythmic drugs on the heart rate and blood pressure response to treadmill exercise

The heart rate and blood pressure response to exercise are clinically important parameters evaluated during treadmill testing. These responses may be altered by cardiac drugs. We evaluated the effect of procainamide and disopyramide on the heart rate and blood pressure response to treadmill exercise in 9 healthy volunteers. Each subject performed one Bruce protocol treadmill test while on each of three treatments: placebo, procainamide 1.0 g t.i.d.; disopyramide 150 mg t.i.d. The order of the treatments was randomized in a Latin square design. The study was conducted double-blind. The drugs slightly increased the resting heart rate, but had no significant effect on exercising heart rate or blood pressure. We conclude that the use of procainamide or disopyramide does not interfere with the interpretation of results of treadmill testing.

Optical absorption resonances of dye-coated silver-island films

We have used Mie theory to account for the features of the transmission spectra of dye-coated silver-island films. The unusual behavior of the spectra arises from the effect of the dispersion and damping of the optical response of the absorbing coating on the structural resonances of the silver islands. Our modeling indicates that the power dissipation in the dye coating is enhanced compared with the dissipation of dye deposited on a nonresonant structure. These results help elucidate the excitation mechanisms of Raman and fluorescent emission of adsorbates at rough silver interfaces.

Optical characterization of powders: the use of Mie theory and composite media models

The measurement of the optical response of materials occurring as finely divided powders is difficult due to the complex interaction of the optical wave with the material. Guided by methods used to study the optical properties of composite media, we have developed experimental and theoretical techniques for characterizing the optical properties of powders. We have applied these techniques to two supported catalysts and have observed several optical effects arising from the very small particle size of these materials.