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Background It is recommended to have 6 bicortical screws for plate fixation of long bone fractures; however, many metacarpal fractures do not allow 6 screws due to size limitations and proximity of crucial anatomical structures. The purpose of this biomechanical study was to determine whether the mechanical properties of a 4-screw nonlocking construct are noninferior to those of a 6-screw nonlocking construct. Methods Metacarpal sawbones were used to simulate a midshaft, transverse fracture. Nonlocking bicortical screws were placed in the 6-hole plate, and the metacarpals were randomly assigned to 2 equal study groups: (1) 4 screws, 2 on either side of the fracture (4S); and (2) 6 screws, 3 on either side of the fracture (6S). The metacarpals were tested in a cyclic loading mode and load to failure in a cantilever bending mode. Results Maximum deflection was significantly higher for 4S compared with 6S. Cyclic root mean square (RMS) was also significantly greater for 4S at 70 and 100 N. There were no statistically significant differences observed between the 2 constructs for maximum bending load, bending stiffness, and cyclic RMS at 40 N. The maximum bending load in 4S and 6S was 245.6 ± 37.9 N and 230.8 ± 41.9 N, respectively; 4S was noninferior and not superior to 6S. Noninferiority testing was inconclusive for bending stiffness. Conclusions A 4-screw bicortical nonlocking construct is noninferior to a 6-screw bicortical nonlocking construct for fixation of metacarpal fractures, which may be advantageous to minimize disruption of soft tissues while maintaining sufficient construct stability.

Background Prehospital plasma transfusion in trauma reduces mortality. However, the underlying mechanism remains unclear. Reduction in shock severity may play a role. Lactate correlates with physiologic shock severity and mortality after injury. Our objective was to determine if prehospital plasma reduces lactate and if this contributes to the mortality benefit of plasma. Methods Patients in the Prehospital Air Medical Plasma trial in the upper quartile of injury severity (Injury Severity Score, >30) were included to capture severe shock. Trial patients were randomized to prehospital plasma or standard care resuscitation (crystalloid ± packed red blood cells). Regression determined the associations between admission lactate, 30-day mortality, and plasma while adjusting for demographics, prehospital crystalloid, time, mechanism, and injury characteristics. Causal mediation analysis determined what proportion of the effect of plasma on mortality is mediated by lactate reduction. Results A total of 125 patients were included. The plasma group had a lower adjusted admission lactate than standard of care group (coefficient, -1.64; 95% confidence interval [CI], -2.96 to -0.31; p = 0.02). Plasma was associated with lower odds of 30-day mortality (odds ratio [OR], 0.27; 95% CI, 0.08-0.90; p = 0.03). When adding lactate to this model, the effect of plasma on 30-day mortality was no longer significant (OR, 0.36; 95% CI, 0.07-1.88; p = 0.23), while lactate was associated with mortality (OR, 1.74 per 1 mmol/L increase; 95% CI, 1.10-2.73; p = 0.01). Causal mediation demonstrated 35.1% of the total effect of plasma on 30-day mortality was mediated by the reduction in lactate among plasma patients. Conclusion Prehospital plasma is associated with reduced 30-day mortality and lactate in severely injured patients. More than one third of the effect of plasma on mortality is mediated by a reduction in lactate. Thus, reducing the severity of hemorrhagic shock appears to be one mechanism of prehospital plasma benefit. Further study should elucidate other mechanisms and if a dose response exists. Level of evidence Therapeutic, level II.

Background: Surgical scrubbing, gowning, and gloving is challenging for medical trainees to learn in the operating room environment. Currently, there are few reliable or valid tools to evaluate a trainee’s ability to scrub, gown and glove. The objective of this study is to test the reliability and validity of a checklist that evaluates the technique of surgical scrubbing, gowning, and gloving. Methods: This Institutional Review Board-approved study recruited medical students, residents, and fellows from an academic, tertiary care institution. Trainees were stratified based upon prior surgical experience as novices, intermediates, or experts. Participants were instructed to scrub, gown and glove in a staged operating room while being video-recorded. Two blinded raters scored the videos according to the SGG checklist. Reliability was assessed using the intraclass correlation coefficient for total scores and Cohen’s kappa for item completion. The internal consistency and discriminant validity of the SGG checklist were assessed using Cronbach alpha and the Wilcoxon rank sum test, respectively. Results: 56 participants were recruited (18 novices, 19 intermediates, 19 experts). The intraclass correlation coefficient demonstrated excellent inter-rater reliability for the overall checklist (0.990), and the Cohen’s kappa ranged from 0.598 to 1.00. The checklist also had excellent internal consistency (Cronbach’s alpha 0.950). A significant difference in scores was observed between all groups (p < 0.001). Conclusion: This checklist demonstrates a high inter-rater reliability, discriminant validity, and internal consistency. It has the potential to enhance medical education curricula.

BACKGROUND Ligamentous ankle injuries are the most common injuries sustained by athletes and by the general population, with an incidence of approximately 2 million per year in the U.S. Injuries to the ankle syndesmosis (i.e., "high ankle sprains") are generally treated operatively. Although cadaveric studies can evaluate syndesmosis fixation strength, they cannot predict how healing, neuromuscular adaptation, or dynamic loading will affect in vivo biomechanics. Using dynamic biplane radiography (DBR), we tested the hypothesis that syndesmosis repair would restore ankle kinematics and ligament elongation during static and dynamic loading. METHODS A convenience sample of 6 male patients who had undergone fixation (2 screw, 3 suspensory, 1 hybrid) of syndesmosis injury were assessed with use of DBR during forward running, backpedaling, a 45° angled single-leg hop, and 1 static standing trial at 2 to 4.5 years postoperatively. Three-dimensional ankle kinematics and elongation of the distal interosseous ligament, anterior inferior tibiofibular ligament, and the posterior inferior tibiofibular ligament were measured bilaterally. Comparisons were made between the operative and uninjured sides. Clinical outcomes were evaluated with use of the Foot and Ankle Ability Measure. RESULTS Static load increased the lengths of the distal interosseous ligament (p = 0.02 to 0.05) and middle segment of the anterior inferior tibiofibular ligament (p = 0.02) in the operative ankle. The distal syndesmosis length was greater on the operative side during the static unloaded and loaded conditions (p = 0.02). Length of the distal syndesmosis on the operative side was greater than the corresponding healthy syndesmosis length during all 3 dynamic activities. On average, the operative ankle was in less dorsiflexion over the support phase of the angled hop (p = 0.05) and running (p < 0.01). The average Foot and Ankle Ability Measure Activities of Daily Living and Sports subscale scores were 95 and 88, respectively. CONCLUSIONS This study provides the first in vivo evidence of post-fixation changes in biomechanics after syndesmosis repair. Syndesmosis repair fails to restore healthy static and dynamic distal tibiofibular anatomy, even in patients who report good to excellent clinical outcomes. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

This paper presents preliminary work on the development of SterileAR, a software platform for providing real-time feedback to pharmacy students during training in sterile pharmaceutical compounding procedures. Simulation pedagogy requires that the learner receive immediate feedback to recognize procedural errors and internalize learning objectives. Instructors and task trainers are often utilized in tandem to allow deliberate practice for novices in specialized clinical procedures. In this work, we explore the possibility of augmenting sterile compounding procedure training with real-time feedback using augmented reality, machine learning, and computer vision technologies. We present our approaches to developing SterileAR in four iterations, including specific descriptions of successes and failures, and methodologies for capturing object spatial position, overlapping, and occlusion.

Objective Two major teaching methods available for learning the pivot shift test are active teaching with real-time feedback from an instructor and passive teaching through the use of instructional textbooks or videos. The purpose of this study was to determine the effect of active and passive teaching methods on the execution of the proper technique of the pivot shift test. Methods Six orthopaedic surgery residents each performed 110 pivot shift tests on a fresh-frozen, cadaveric pelvis-to-toe specimen with anterior cruciate ligament insufficiency and lateral meniscectomy. Participants performed 10 repetitions before teaching and a total of 100 repetitions after either active or passive teaching. Six degree-of-freedom kinematics of the knee defined by the Grood/Suntay coordinate system were recorded after every fifth repetition using an electromagnetic tracking system. Anterior/posterior translation of the lateral knee compartment during the reduction event was also quantified. Depending on the normality of the data, a two-tailed t-test or Wilcoxon rank-sum test was used for comparisons of kinematics between the active and passive teaching groups and between successful and unsuccessful trials within each teaching group. Statistical significance was set at p Results The success rate after active teaching was 31.7% compared with 30.0% after passive teaching. However, the starting position of the reduction event in the active teaching group was rotated by more than twice the amount of valgus rotation compared with the passive group (7.4°±3.3° vs 3.0°±2.7°; p Conclusion Successful pivot shift tests can be performed after passive teaching, but the standard technique is not as effectively learnt through passive teaching since traditional external rotation during the reduction event was not used as in the active teaching group. Level of evidence V.

The aims of this study were to compare male versus female and dominant versus non-dominant kinematics in the ankle and hindfoot, and to characterize coupled motion between the subtalar and tibiotalar joints during the support phase of gait. Twenty healthy adults walked on a laboratory walkway while synchronized biplane radiographs of the ankle and hindfoot were collected at 100 frames/s. A validated tracking technique was used to measure tibiotalar and subtalar kinematics. Differences between male and female range of motion (ROM) were observed only in tibiotalar (AP and ML) and subtalar (ML) translation (all differences1 mm and all p 0.04). Statistical parametric mapping identified differences between kinematics waveforms of males and females in tibiotalar translation (AP and ML) and eversion, and subtalar ML translation. No differences between dominant and non-dominant sides were observed in ROM or kinematics waveforms. The average absolute side-to-side difference in the kinematics waveforms was 4.1° and 1.5 mm or less for all rotations and translations, respectively. Tibiotalar plantarflexion was coupled to subtalar inversion and eversion during the impact and push-off phases of stance (r = 0.90 and r = 0.87, respectively). This data may serve as a guide for evaluating ankle kinematics waveforms, ROM, symmetry, and restoration of healthy coupled motion after surgical intervention or rehabilitation. The observed kinematics differences between males and females may predispose females to higher rates of ankle and knee injury and suggest sex-dependent ankle reconstruction techniques may be beneficial.

Category: Trauma; Basic Sciences/Biologics Introduction/Purpose: Syndesmotic injuries account for 1-11% of all ankle sprains and are the most predictive factor of chronic ankle dysfunction 6 months after injury. Common surgical techniques include screw fixation (the ‘gold standard’) and dynamic fixation with a suture button device, which may lead to better clinical outcomes than rigid screw. To date, there are no studies comparing the in vivo biomechanics of suture button and rigid screw syndesmotic fixation, and no report of the correlations between biomechanics and patient outcomes. The goal of this study is to characterize the biomechanics of the native ankle syndesmosis, rigid screw fixation, suture button fixation, along with associated patient-reported outcomes. This study will elucidate mechanisms for improved patient-reported outcomes based on the fixation method. Methods: 6 patients (average age:23.6, 4M/1F, 2 suture button, 2 screw fixation and 1 hybrid) consented to participate in this IRB-approved study. After being medically cleared to return to full athletic participation, each participant performed seven movements (two single leg hops (straight and lateral), two alternating single-leg push-offs (front-to-back and side-to-side), vertical jumping, running, and walking within a biplane radiographic system (Figure 1). A validated volumetric model-based tracking system matched patient-specific 3D bone models (obtained from CT) to the synchronized biplane radiographs (Figure 1). Six degree of freedom ankle kinematics were determined for each movement and for the repaired and contralateral ankle of each participant. Patient reported outcomes were also measured using the Foot and Ankle Ability Measure (FAAM) and a Visual Analogue Scale (VAS). Results: The results show that the screw fixation (-0.99 mm) has greater tibiotalar lateral-medial translation of the injured side relative contralateral healthy side compared to the tightrope fixation (-0.73 mm) and hybrid (.05 mm). For the syndesmosis translation, the screw fixation (2.00 mm) also exhibits greater total magnitude of translation compared to the tightrope ((-0.44 mm) and hybrid fixation (1.02 mm). Conclusion: This study shows that the screw fixation exhibits greater translation of the syndemosis and lateral/medial translation of the Talus. This may suggest that this method is inferior to the tight-rope and hybrtid. Future studies will include all the motions and more subjects.

Category: Sports Introduction/Purpose: The percentage of the U.S population that is age 65 and older is expected to rise to 19.3% by the year 2030, up from 13% in 2010. Only 39% of seniors get the recommended amount of weekly exercise. This has led to Medicare sponsored fitness plans to increase of the number of older adults being active. For this percentage it is important that they are aware of safety precautions and ways to prevent injuries. One study showed that in elderly men still active in sports 75% of injuries were located in the lower extremity. The purpose of this study is to trend sports related foot and ankle (SFA) injuries in patients 65 and over that presented emergency departments from 2009 to 2018. Methods: Data was obtained from the National Electronic Injury Surveillance System (NEISS). Injury data is obtained daily from the emergency departments of approximately 100 hospitals across the United States and its territories. This serves as a probability sample of over 5000 hospitals across the country. Each case recorded is given a statistical weight based on the study design. CPSC analysis has the ability to make adjustments to more accurately represent the entire United States population. Hospitals are group in five strata mostly based on hospital size and number of ED visits they receive per year. The database was set with query inputs of patients aged 65 and over that presented with sports related injuries of the lower leg, ankle, foot and toes from 2009 - 2018. Results: An approximate total of 216,334 SFA injuries presented to emergency rooms in persons age 65 and over. Contusions/abrasions accounted for 11.7% of total injuries; lacerations (12.4%); fractures (20.9%); sprains and fractures (22.7%). Other types of injuries accounted for 32.3 %. There was an approximate total of 1,654,666 sports related injuries. Upper extremity had the highest percentage at 24.6%. Ages 65-69 accounted for 38.8 %. The trend for the SFA injuries increased 39.9% from 2009 to 2018, while the trend for overall sports injuries rose 83%. The percentage of SFA out of all sports injuries has decreased 23.6% from 14.81% of total sport injuries in 2009 to 11.32% in 2018. Conclusion: As the population ages, more seniors are remaining active and more are participating in sports. Thus, the increase in the number of sport related injuries. This increase however has outpaced the number of foot and ankle specific sport injuries. Over the time span of the study there has been an increase in percentage of hand, wrist and knee injuries. Further research is needed to delineated which specific sports and activities cause the most SFA injuries. This information can then be used to educate this population on injury prevention.

This article was migrated. The article was not marked as recommended. Background Competency in surgical scrubbing, gowning and gloving (scrubbing-in) procedures is necessary to participate in surgery, but difficult for trainees to learn due to the fast pace of the operating room and limited availability of experts to provide training. Current methods of scrubbing-in procedures are antiquated. Simulation-based education aligns with the paradigm shift occurring in medical education as we transition from passive models. This study utilized the Delphi technique to identify necessary items to include in a scrubbing-in checklist that can be used in future simulation and assessment tools.MethodsSurgeon experts participated in three rounds of a Delphi process. The panel consisted of surgical specialty residents, fellows and attending surgeons from gynecology, urology, general surgery, plastic, orthopedic and neurosurgery.ResultsFrom January 2018 to September 2018, 39 experts from 6 different surgical subspecialties participated in three Delphi survey rounds. Of the 43 items identified during the first round, 30 (70%) resulted with an importance rating > 4.0. During the final round, a consensus of > 85% was reached for 22 total items (73%).ConclusionWe developed a 22-step checklist for scrubbing-in procedures utilizing the Delphi technique. This checklist will enhance undergraduate medical education simulation curriculums and assessments.

Current research has yet to determine how passive dynamics and active neural control contribute to upper limb swing during human locomotion. The present study aimed to investigate these contributions by restricting pelvis motion during walking, thereby altering the upward energy transfer from the swinging lower limbs. Ten healthy individuals walked freely on a treadmill (CON) and with an apparatus that reduced pelvis motion (PR) at three walking speeds (0.9, 1.3, and 1.8m/s). Spatiotemporal characteristics of limb movement and muscle activation were recorded and analyzed. When wearing the apparatus, the ranges of the sagittal and transverse rotations of the trunk and shoulders, as well as vertical trunk center of mass movement all decreased. At higher treadmill speeds, the movement amplitudes of the upper and lower limbs increased. This increase was less pronounced in the upper limbs when the apparatus reduced pelvis motion. However, this decrease in arm swing was accompanied with a preservation of upper and lower limb muscle activity amplitudes. The temporal coordination between upper and lower limbs was also conserved irrespective of the PR or CON conditions. Relating shoulder muscle activities to upper limb kinematics suggested these muscles mainly acted eccentrically, providing evidence that passive elements are a significant factor in arm swing control. However, the conserved muscle activity patterns and temporal coupling of limb movements when pelvis motion was reduced are suggestive of an underlying active maintenance of the locomotor pattern via linked upper and lower limb neural networks.

The goal of this paper is to demonstrate a novel approach that combines Empirical Mode Decomposition (EMD) with Notch filtering to remove the electrical stimulation (ES) artifact from surface electromyogram (EMG) data for interpretation of muscle responses during functional electrical stimulation (FES) experiments. FES was applied to the rectus femoris (RF) muscle unilaterally of six able bodied (AB) and one individual with spinal cord injury (SCI). Each trial consisted of three repetitions of ES. We hypothesized that the EMD algorithm provides a suitable platform for decomposing the EMG signal into physically meaningful intrinsic mode functions (IMFs) which can be further used to isolate electrical stimulation (ES) artifact. A basic EMD algorithm was used to decompose the EMG signals collected during FES into IMFs for each repetition separately. IMFs most contaminated by ES were identified based on the standard deviation (SD) of each IMF. Each artifact IMF was Notch filtered to filter ES harmonics and added to remaining IMFs containing pure EMG data to get a version of a filtered EMG signal. Of all such versions of filtered signals generated from each artifact IMF, the one with maximum signal to noise ratio (SNR) was chosen as the final output. The validity of the filtered signal was assessed by quantitative metrics, 1) root mean squared error (RMSE) and signal to noise (SNR) ratio values obtained by comparing a clean EMG and EMD-Notch filtered signal from the combination of simulated ES and clean EMG and, 2) using EMG-force correlation analysis on the data collected from AB individuals. Finally, the potential applicability of this algorithm on a neurologically impaired population was shown by applying the algorithm on EMG data collected from an individual with SCI. EMD combined with Notch filtering successfully extracted the EMG signal buried under ES artifact. Filtering performance was validated by smaller RMSE values and greater SNR post filtering. The amplitude values of the filtered EMG signal were seen to be consistent for three repetitions of ES and there was no significant difference among the repetition for all subjects. For the individual with a SCI the algorithm was shown to successfully isolate the underlying bursts of muscle activations during FES. The data driven nature of EMD algorithm and its ability to act as a filter bank at different bandwidths make this method extremely suitable for dissecting ES induced EMG into IMFs. Such IMFs clearly show the presence of ES artifact at different intensities as well as pure artifact free EMG. This allows the application of Notch filters to IMFs containing ES artifact to further isolate the EMG. As a result of such stepwise approach, the extraction of EMG is achieved with minimal data loss. This study provides a unique approach to dissect and interpret the EMG signal during FES applications.

The goal of this research is to assess how powered exoskeleton-training for 5 h per week over 20 weeks can change gait parameters to increase walking speed for chronic SCI. Gait parameters include Center of Mass (CoM) excursions, walking velocity, initial double stance time (IDS), single stance time (SS), terminal double stance time (TDS), swing time (SW), and spatial parameters such as step length, step width and stride length. Exoskeleton training had a significant effect on walking velocity due to specific temporal spatial gait parameters (IDS, TDS, Step and Stride Length) and increased stability (CoM).

The goal of this paper is to study the effects of supine and stand retraining (SRT) interventions with and without multi muscle neuromuscular electrical stimulation (NMES) on the neuromuscular EMG responses of the leg muscles for individuals with motor complete SCI during walking on a body-weight support (BWS) treadmill. The main outcome variables were EMG amplitude, integrated EMG and co-contraction indices (co-excitation and co-activation) collected during a 10-minute walking treadmill trial. Data was analyzed for the first, fifth and tenth minute of walking. Results showed that both Supine+NMES and SRT+NMES interventions increased spatial-temporal aspects of muscle activity (mean EMG amplitude and integrated EMG) of lower limb muscles. SRT+NMES (loading) showed greater gains in the proximal anterior leg compartments. On the contrary, SRT without NMES (SRT only) exhibited deterioration of activity within the same muscle groups. Co-contraction indices increased for both post-NMES interventions suggesting that task-specificity of training is important to achieve the fundamental reciprocal firing known to able-bodied gait. These results show that combination of NMES+loading during passive rhythmic gait will induce neuroplasticity in the lower limbs that ultimately provides a potential effective means to recover gait in individuals with SCI.