Analysis of Pushing Forces During the Water Polo Eggbeater: Reliability and Validity of a Novel Approach.

Water polo players benefit from greater odds of success when maintaining their tactical position against their opponents. This study evaluated the reliability and validity of a water-based resistance test to replicate this skill.Thirty-three water polo players participated in this study (19 males and 14 females, 14 from senior and 19 from junior national teams). Data were collected during two regular training sessions, separated by one week, using a load cell to instrument a weight stack resistance setup on the pool deck. Performance parameters such as mean force, maximum force, mean peak force and total impulse were defined with custom Python scripts. Test-retest reliability was assessed using intra-class correlations (ICC3,1). Group comparisons were explored between male and female players. Level of significance was set at p < 0.05. The reliability findings were high to very high for the mean force, maximum force, mean peak force, inter-stroke range, and total impulse (ICC 0.85-0.93, p < 0.01). Group comparisons showed significantly greater values in male players for these variables (p < 0.01, ES = 1.05-9.36) with large to very large effect sizes. However, there was no significant difference in endurance measured between sexes (p = 0.88, ES = 0.04). This study presents a methodology with satisfactory metrological qualities for field applications using simple and affordable equipment. The testing apparatus presented in this study can readily be replicated in a variety of training environments by practitioners working with water polo teams. Coaches can use this approach to evaluate individual player progress or to compare performance across a group of water polo players.

Injury outcomes across Canadian trauma systems: a historical cohort study.

PURPOSE: Most North American trauma systems have designated trauma centres (TCs) including level I (ultraspecialized high-volume metropolitan centres), level II (specialized medium-volume urban centres), and/or level III (semirural or rural centres). Trauma system configuration varies across provinces and it is unclear how these differences influence patient distributions and outcomes. We aimed to compare patient case mix, case volumes, and risk-adjusted outcomes of adults with major trauma admitted to designated level I, II, and III TCs across Canadian trauma systems. METHODS: In a national historical cohort study, we extracted data from Canadian provincial trauma registries on major trauma patients treated between 2013 and 2018 in all designated level I, II, or III TCs in British Columbia, Alberta, Quebec, and Nova Scotia; level I and II TCs in New Brunswick; and four TCs in Ontario. We used multilevel generalized linear models to compare mortality and intensive care unit (ICU) admission and competitive risk models for hospital and ICU length of stay (LOS). Ontario could not be included in outcome comparisons because there were no population-based data from this province. RESULTS: The study sample comprised 50,959 patients. Patient distributions in level I and II TCs were similar across provinces but we observed significant differences in case mix and volumes for level III TCs. There was low variation in risk-adjusted mortality and LOS across provinces and TCs but interprovincial and intercentre variation in risk-adjusted ICU admission was high. CONCLUSIONS: Our results suggest that differences in the functional role of TCs according to their designation level across provinces leads to significant variations in the distribution of patients, case volumes, resource use, and clinical outcomes. These results highlight opportunities to improve Canadian trauma care and underline the need for standardized population-based injury data to support national quality improvement efforts.

RéSUMé: OBJECTIF: La plupart des systèmes de traumatologie nord-américains disposent de centres de traumatologie (CT) désignés, y compris de niveau I (centres métropolitains ultraspécialisés à volume élevé), de niveau II (centres urbains spécialisés à volume moyen) et/ou de niveau III (centres semi-ruraux ou ruraux). La configuration des systèmes de traumatologie varie d'une province à l'autre et nous ne savons pas comment ces différences influent sur la répartition de la patientèle et sur les issues. Notre objectif était de comparer le mélange de cas des patient·es, le volume de cas et les issues ajustées en fonction du risque des adultes ayant subi un traumatisme majeur admis·es dans des CT désignés de niveaux I, II et III dans l'ensemble des systèmes de traumatologie canadiens. MéTHODE: Dans une étude de cohorte historique nationale, nous avons extrait des données des registres provinciaux canadiens de traumatologie sur les patient·es ayant subi un traumatisme majeur traité·es entre 2013 et 2018 dans tous les CT désignés de niveau I, II ou III en Colombie-Britannique, en Alberta, au Québec et en Nouvelle-Écosse, les CT de niveau I et II au Nouveau-Brunswick, et dans quatre CT en Ontario. Nous avons utilisé des modèles linéaires généralisés à plusieurs niveaux pour comparer la mortalité, les admissions en unité de soins intensifs (USI) et les modèles de risque compétitif pour la durée du séjour à l'hôpital et à l'USI. L'Ontario n'a pas pu être inclus dans les comparaisons des devenirs parce qu'il n'y avait pas de données démographiques pour cette province. RéSULTATS: L'échantillon de l'étude comptait 50 959 patient·es. La répartition des patient·es dans les CT de niveaux I et II était similaire d'une province à l'autre, mais nous avons observé des différences significatives dans le mélange des cas et les volumes pour les CT de niveau III. Il y avait une faible variation de la mortalité ajustée en fonction du risque et des durées de séjour entre les provinces et les CT, mais la variation interprovinciale et intercentre des admissions à l'USI ajustées en fonction du risque était élevée. CONCLUSION: Nos résultats suggèrent que les différences dans le rôle fonctionnel des CT selon leur niveau de désignation d'une province à l'autre entraînent des variations importantes dans la répartition des patient·es, le nombre de cas, l'utilisation des ressources et les issues cliniques. Ces résultats mettent en évidence les possibilités d'amélioration des soins de traumatologie au Canada et soulignent la nécessité de disposer de données normalisées sur les blessures dans la population pour appuyer les efforts nationaux d'amélioration de la qualité.

Case study of IMU loads and self-reported fatigue monitoring of water polo goalkeepers preparing for the Olympic games.

Introduction: Measurement of training in water polo goalkeepers has focused first on psycho-physiological variables, but also on external volume estimated with wearable sensors. However, there are limited studies exploring training monitoring in water polo goalkeepers longitudinally. Methods: Three female senior national team goalkeepers participated in this study from May to August 2021. Internal loads were defined using session rating of perceived exertion (sRPE). Tri-axial accelerations and angular velocities were measured with an inertial measurement unit (IMU) placed on the lower back to measure external loads. Relationships between self-reported and IMU-derived metrics were explored using Spearman correlations. Two-way ANOVAs were used to assess differences between session types and between athletes. Results: In total, 247 sessions were collected (159 practices, 67 matches and 21 game warm up), with 155 sessions having complete data. IMU metrics, such as number of kicks, number of jumps or player-load showed high correlation with each other (ρ = 0.80-0.88). There was also a moderate correlation (ρ = 0.47, 95% CI = 0.33-0.58) between sRPE and player-load measured with the IMU. ANOVA tests showed that there were significant differences between athletes for sRPE (p < 0.01) but not for player load (p = 0.47). There were no interactions between athletes and training types, except for index score (p < 0.01). Conclusions: This study shows that monitoring of training loads can be performed successfully in water polo goalkeepers using a combination of self-reported and IMU measures. Self-reported outcomes can be expected to vary significantly across athletes within the same session, while IMU metrics vary across training situations. Finally, coaches should be mindful of missing data, as they can skew the interpretation of training loads.

Validation of Automatically Quantified Swim Stroke Mechanics Using an Inertial Measurement Unit in Paralympic Athletes.

Biomechanics and training load monitoring are important for performance evaluation and injury prevention in elite swimming. Monitoring of performance and swim stroke parameters is possible with inertial measurement units (IMU) but has not been validated in para-swimmers. The purpose of this study was to validate a single IMU-based system to accurately estimate pool-swam lap time, stroke count (SC), stroke duration, instantaneous stroke rate (ISR), and distance per stroke (DPS). Eight Paralympic athletes completed 4 × 50 m swims with an IMU worn on the sacrum. Strokes cycles were identified using a zero-crossing algorithm on the medio-lateral (freestyle and backstroke) or forward-backward (butterfly and breaststroke) instantaneous velocity data. Video-derived metrics were estimated using Dartfish and Kinovea. Agreement analyses, including Bland-Altman and Intraclass Correlation Coefficient (ICC), were performed on all outcome variables. SC Bland-Altman bias was 0.13 strokes, and ICC was 0.97. ISR Bland-Altman biases were within 1.5 strokes/min, and ICCs ranged from 0.26 to 0.96. DPS Bland-Altman biases were within 0.20 m, and ICCs ranged from 0.39 to 0.93. A single-IMU system can provide highly valid performance and swim stroke monitoring data for elite para-swimmers for the majority of strokes, with the exception of backstroke. Future work should improve bilateral stroke detection algorithms in this population.

Pre- and posttransfer computed tomography imaging in Canadian trauma centers: A multicenter retrospective cohort study.

BACKGROUND: Multiple clinical practice guidelines recommend minimizing radiation in trauma patients but there is a knowledge gap on the importance of this problem for trauma transfers. We aimed to estimate the incidence of pretransfer and repeat posttransfer computed tomography (CT) overall and in patients with an indication for immediate transfer, to assess interhospital practice variation, to identify predictors, and to quantify the influence of pretransfer CT on time to transfer. Methods We conducted a retrospective multicenter cohort study on patients transferred to major trauma centers from 2013 to 2019. Multilevel generalized linear regression was used to generate intraclass correlation coefficients (ICCs) to assess interhospital variation, multilevel logistic regression to generate odds ratios for each predictor, and geometric mean ratios to quantify the influence of CT on time to transfer. Results Of 18,244 patients included, 8501 (47%) had a pretransfer CT and one-quarter (26%) had a repeat posttransfer CT. Interhospital variation was moderate for pretransfer CT (5%-66%, ICC 12.5%) and for repeat posttransfer CT (7%-44%, ICC 14.7%). Pretransfer imaging was more frequent in elders and in males and repeat posttransfer imaging decreased over the study period but was more frequent in patients transferred in from Level III/IV centers than nondesignated hospitals. Time to transfer was doubled in patients who had a pretransfer CT. CONCLUSIONS: Results suggest that pretransfer CT and repeat posttransfer CT are frequent and are subject to significant practice variation. In addition, pretransfer CT is associated with increased times to transfer though additional studies are needed to demonstrate causation. These results highlight potential opportunities to reduce low-value imaging for trauma transfers.

Quantifying Utilitarian Outcomes to Inform Triage Ethics: Simulated Performance of a Ventilator Triage Protocol under Sars-CoV-2 Pandemic Surge Conditions.

BACKGROUND: Equitable protocols to triage life-saving resources must be specified prior to shortages in order to promote transparency, trust and consistency. How well proposed utilitarian protocols perform to maximize lives saved is unknown. We aimed to estimate the survival rates that would be associated with implementation of the New York State 2015 guidelines for ventilator triage, and to compare them to a first-come-first-served triage method. METHODS: We constructed a simulation model based on a modified version of the New York State 2015 guidelines compared to a first-come-first-served method under various hypothetical ventilator shortages. We included patients with SARs-CoV-2 infection admitted with respiratory failure requiring mechanical ventilation to three acute care hospitals in New York from 3/01/2020 and 5/27/2020. We estimated (1) survival rates, (2) number of excess deaths, (3) number of patients extubated early or not allocated a ventilator due to capacity constraints, (4) survival rates among patients not allocated a ventilator at triage or extubated early due to capacity constraints. RESULTS: 807 patients were included in the study. The simulation model based on a modified New York State policy did not decrease mortality, excess death or exclusion from ventilators compared to the first-come-first-served policy at every ventilator capacity we tested using COVID-19 surge cohort patients. Survival rates were similar at all the survival probabilities estimated. At the lowest ventilator capacity, the modified New York State policy has an estimated survival of 28.5% (CI: 28.4-28.6), compared to 28.1% (CI: 27.7-28.5) for the first-come-first-served policy. CONCLUSIONS: This simulation of a modified New York State guideline-based triage protocol revealed limitations in achieving the utilitarian goals these protocols are designed to fulfill. Quantifying these outcomes can inform a better balance among competing moral aims.

Intensity of hospital resource use following traumatic brain injury: a multicentre cohort study, 2013-2016.

BACKGROUND: The knowledge gap regarding acute care resource use for patients with traumatic brain injury (TBI) impedes efforts to improve the efficiency and quality of the care of these patients. Our objective was to evaluate interhospital variation in resource use for patients with TBI, identify determinants of high resource use and assess the association between hospital resource use and clinical outcomes. METHODS: We conducted a multicentre retrospective cohort study including patients aged 16 years and older admitted to the inclusive trauma system of Quebec following TBI, between 2013 and 2016. We estimated resource use using activity-based costs. Clinical outcomes included mortality, complications and unplanned hospital readmission. Interhospital variation was evaluated using intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Correlations between hospital resource use and clinical outcomes were evaluated using correlation coefficients on weighted, risk-adjusted estimates with 95% CIs. RESULTS: We included 6319 patients. We observed significant interhospital variation in resource use for patients discharged alive, which was not explained by patient case mix (ICC 0.052, 95% CI 0.043 to 0.061). Adjusted mean resource use for patients discharged to long-term care was more than twice that of patients discharged home. Hospitals with higher resource use tended to have a lower incidence of mortality (r -0.347, 95% CI -0.559 to -0.087) and unplanned readmission (r -0.249, 95% CI -0.481 to 0.020) but a higher incidence of complications (r 0.491, 95% CI 0.255 to 0.666). CONCLUSION: Resource use for TBI varies significantly among hospitals and may be associated with differences in mortality and morbidity. Negative associations with mortality and positive associations with complications should be interpreted with caution but suggest there may be a trade-off between adverse events and survival that should be evaluated further.

Interhospital Variations in Resource Use Intensity for In-hospital Injury Deaths: A Retrospective Multicenter Cohort Study.

OBJECTIVE: Evaluate interhospital variation in resource use for in-hospital injury deaths. BACKGROUND: Significant variation in resource use for end-of-life care has been observed in the US for chronic diseases. However, there is an important knowledge gap on end-of-life resource use for trauma patients. METHODS: We conducted a multicenter, retrospective cohort study of injury deaths following hospitalization in any of the 57 trauma centers in a Canadian trauma system (2013-2016). Resource use intensity was measured using activity-based costing (2016 $CAN) according to time of death (72 h, 3-14 d, ≥14 d). We used multilevel log-linear regression to model resource use and estimated interhospital variation using intraclass correlation coefficients (ICC). RESULTS: Our study population comprised 2044 injury deaths. Variation in resource use between hospitals was observed for all 3 time frames (ICC = 6.5%, 6.6%, and 5.9% for < 72 h, 3-14 d, and ≥14 d, respectively). Interhospital variation was stronger for allied health services (ICC = 18 to 26%), medical imaging (ICC = 4 to 10%), and the ICU (ICC = 5 to 6%) than other activity centers. We observed stronger interhospital variation for patients < 65 years of age (ICC = 11 to 34%) than those ≥65 (ICC = 5 to 6%) and for traumatic brain injury (ICC = 5 to 13%) than other injuries (ICC = 1 to 8%). CONCLUSIONS: We observed variation in resource use intensity for injury deaths across trauma centers. Strongest variation was observed for younger patients and those with traumatic brain injury. Results may reflect variation in level of care decisions and the incidence of withdrawal of life-sustaining therapies.

Derivation and validation of actionable quality indicators targeting reductions in complications for injury admissions.

PURPOSE: Approximately, one out of five patients hospitalized following injury will develop at least one hospital complication, more than three times that observed for general admissions. We currently lack actionable Quality Indicators (QI) targeting specific complications in this population. We aimed to derive and validate QI targeting hospital complications for injury admissions and develop algorithms to identify patient charts to review. METHODS: We conducted a retrospective cohort study including patients with major trauma admitted to any level I or II adult trauma center an integrated Canadian trauma system (2014-2019). We used the trauma registry to develop five QI targeting deep vein thrombosis/pulmonary embolism (DVT/PE), decubitus ulcers, delirium, pneumonia and urinary tract infection (UTI). We developed algorithms to identify patient charts to revise on consultation with a group of clinical experts. RESULTS: The study population included 14,592 patients of whom 5.3% developed DVT or PE, 2.7% developed a decubitus ulcer, 8.6% developed delirium, 14.7% developed pneumonia and 7.3% developed UTI. The indicators demonstrated excellent predictive performance (Area Under the Curve 0.81-0.87). We identified 4 hospitals with a higher than average incidence of at least one of the targeted complications. The algorithms identified on average 50 and 20 charts to be reviewed per year for level I and II centers, respectively. CONCLUSION: In line with initiatives to improve the quality of trauma care, we propose QI targeting reductions in hospital complications for injury admissions and algorithms to generate case lists to facilitate the review of patient charts.

Adherence to Clinical Practice Guideline Recommendations on Low-Value Injury Care: A Multicenter Retrospective Cohort Study.

OBJECTIVES: Low-value clinical practices have been identified as one of the most important areas of excess healthcare spending. Nevertheless, there is a knowledge gap on the scale of this problem in injury care. We aimed to identify clinical practice guideline (CPG) recommendations pertaining to low-value injury care, estimate how frequently they are used in practice, and evaluate interhospital variations in their use. METHODS: We identified low-value clinical practices from internationally recognized CPGs. We conducted a retrospective cohort study using data from a Canadian trauma system (2014-2019) to calculate frequencies and assess interhospital variations. RESULTS: We identified 29 low-value practices. Fourteen could be measured using trauma registry data. The 3 low-value clinical practices with the highest absolute and relative frequencies were computed tomography (CT) in adults with minor head injury (n = 5591, 24%), cervical spine CT (n = 2742, 31%), and whole-body CT in minor or single-system trauma (n = 530, 32%). We observed high interhospital variation for decompressive craniectomy in diffuse traumatic brain injury. Frequencies and interhospital variations were low for magnetic resonance imaging, intracranial pressure monitoring, inferior vena cava filter use, and surgical management of blunt abdominal injuries. CONCLUSIONS: We observed evidence of poor adherence to CPG recommendations on low-value CT imaging and high practice variation for decompressive craniectomy. Results suggest that adherence to recommendations for the 10 other low-value practices is high. These data can be used to advance the research agenda on low-value injury care and inform the development of interventions targeting reductions in healthcare overuse in this population.

A Delphi study to identify prehospital and emergency department trauma care modifiers for older adults.

Background: Older patients (age ≥ 65 yr) with trauma have increased morbidity and mortality compared to younger patients; this is partly explained by undertriage of older patients with trauma, resulting in lack of transfer to a trauma centre or failure to activate the trauma team. The objective of this study was to identify modifiers to the prehospital and emergency department phases of major trauma care for older adults based on expert consensus. Methods: We conducted a modified Delphi study between May and September 2019 to identify major trauma care modifiers for older adults based on national expert consensus. The panel consisted of 24 trauma care professionals from across Canada from the prehospital and emergency department phases of care. The survey consisted of 16 trauma care modifiers. Three online survey rounds were distributed. Consensus was defined a priori as a disagreement index score less than 1. Results: There was a 100% response rate for all survey rounds. Three new trauma care modifiers were suggested by panellists. The panel achieved consensus agreement for 17 of the 19 trauma care modifiers. The prehospital modifier with the strongest agreement to transfer to a trauma centre was a respiratory rate less than 10 or greater than 20 breaths/min or need for ventilatory support. The emergency department modifier with the strongest level of agreement was obtaining 12-lead electrocardiography following the primary and secondary survey. Conclusion: Using a modified Delphi process, an expert panel agreed on 17 trauma care modifiers for older adults in the prehospital and emergency department settings. These modifiers may improve the delivery of trauma care for older adults and should be considered when developing local and national trauma guidelines.

Contexte: Les polytraumatisés âgés (≥ 65 ans) sont exposés à un risque plus grand de morbidité et de mortalité comparativement aux jeunes polytraumatisés; cela s'explique en partie par un triage inadéquat des patients âgés victimes de traumatismes, qui fait en sorte qu'on ne les oriente pas vers un centre de traumatologie ou qu'on ne fait pas intervenir l'équipe de traumatologie. L'objectif de la présente étude était d'identifier les éléments de soins à modifier au stade préhospitalier et en médecine d'urgence lors de la prise en charge des cas de traumatismes graves chez les adultes âgés, sur la base d'un consensus d'experts. Méthodes: Nous avons procédé à une analyse Delphi modifiée entre mai et septembre 2019 pour recenser les éléments de soins à modifier chez les polytraumatisés âgés à partir d'un consensus national d'experts. Le panel d'experts se composait de 24 professionnels en traumatologie du Canada entier chargés des soins au stade préhospitalier et en médecine d'urgence. Le questionnaire portait sur 16 éléments à modifier en traumatologie. Trois questionnaires successifs ont été distribués en ligne. Le consensus était défini a priori par un indice de désaccord inférieur à 1. Résultats: Le taux de réponse a été de 100 % pour les 3 questionnaires. Les membres du comité ont suggéré 3 nouveaux éléments à modifier. Le comité est arrivé à un consensus pour 17 des éléments à modifier sur 19. L'élément préhospitalier ayant fait l'objet du plus solide consensus concernant le transfert vers un centre de traumatologie était une fréquence respiratoire inférieure à 10 ou supérieure à 20 respirations/minute ou la nécessité d'une assistance respiratoire. L'élément à modifier parmi les soins prodigués à l'urgence ayant fait l'objet du plus solide consensus après les 2 premiers questionnaires était l'obtention d'un électrocardiogramme à 12 dérivations. Conclusion: À l'aide d'une analyse Delphi modifiée, un comité d'expert s'est entendu sur 17 éléments de soins à modifier chez les polytraumatisés âgés au stade préhospitalier et en médecine d'urgence. Ces éléments pourraient améliorer les soins aux adultes âgés et méritent d'être pris en compte lors de la création de lignes directrices locales et nationales en traumatologie.

Instantaneous velocity estimation for the four swimming strokes using a 3-axis accelerometer: Validation on paralympic athletes.

Inertial measurement unit systems (IMU) are increasingly used in sports. However, no algorithm evaluating the instantaneous swimming velocity has been validated on the four swimming strokes, or on dive start. Our objective is to develop and validate a new method to measure instantaneous swimming velocity on athletes presenting various musculoskeletal and neurological impairments and swimming one of the four swimming strokes. Seven Paralympic athletes were involved and performed a total of 18 trials of 50 m in real conditions. All trials were recorded with a 3-axis accelerometer, a tethered device and a video camera. The instantaneous velocity was computed by drift-free integration of the forward acceleration. For all trials, Bland-Altman analyses showed a bias of 0.03-0.06 m.s-1 with the tethered device, with 95% LOA lower than 0.31-0.80 m.s-1, RMSE was 0.14-0.39 m.s-1, and ICC amounted 0.494-0.941. No significant difference was found for the mean 50 m velocities between the accelerometer, the tethered device and the video camera. The results obtained for freestyle were comparable to those obtained with GPS in outdoor pools. Those obtained for backstroke, breaststroke and butterfly were very encouraging. Our method is simple, reliable, advantageous compared to tethered devices, and could be easily used in the field by coaches.

Value of repeat CT for nonoperative management of patients with blunt liver and spleen injury: a systematic review.

PURPOSE: To evaluate the effectiveness of routine repeat computed tomography (CT) for nonoperative management (NOM) of adults with blunt liver and/or spleen injury. METHODS: We conducted a systematic review of randomized and non-randomized controlled trials (RCTs), quasi-experimental and observational studies of repeat CT in adult patients with blunt abdominal injury. We searched Medline, Embase, Web of Science, and Cochrane Central from their inception to October 2020 using Cochrane guidelines. Primary outcomes were change in clinical management (e.g., emergency surgery, embolization, blood transfusion, clinical surveillance), mortality, and complications. Secondary outcomes were hospital readmission and length of stay. RESULTS: Search results yielded 1611 studies of which 28 studies including 2646 patients met our inclusion criteria. The majority reported on liver (n = 9) or spleen injury (n = 16) or both (n = 3). No RCTs were identified. Meta-analyses were not possible because no study performed direct comparisons of study outcomes across intervention groups. Only seven of the twenty-eight studies reported whether repeat CT was routine or prompted by clinical indication. In these 7 studies, among the 254 repeat CT performed, 188 (74%) were routine and 8 (4%) of these led to a change in clinical management. Of the 66 (26%) repeated CT prompted by clinical indication, 31 (47%) led to a change in management. We found no data allowing comparison of any other outcomes across intervention groups. CONCLUSION: Routine repeat CT without clinical indication is not useful in the management of patients with liver and/or spleen injury. However, effect estimates were imprecise and included studies were of low methodological quality. Given the risks of unnecessary radiation and costs associated with repeat CT, future research should aim to estimate the frequency of such practices and assess practice variation. LEVEL OF EVIDENCE: Systematic reviews and meta-analyses, Level II.

Inter-hospital variation in surgical intensity for trauma admissions: A multicentre cohort study.

BACKGROUND: Guidelines for injury care are increasingly moving away from surgical management towards less invasive procedures but there is a knowledge gap on how these recommendations are influencing practice. We aimed to assess inter-hospital variation in surgical intensity for injury admissions and evaluate the correlation between hospital surgical intensity and mortality/complications. METHODS: We included adults admitted for major trauma between 2006 and 2016 in a Canadian provincial trauma system. Analyses were stratified for orthopaedic (n = 16 887), neurological (n = 12 888) and torso injuries (n = 9816). Surgical intensity was quantified with the number of surgical procedures <72 hours. Inter-hospital variation was assessed with the intra-class correlation coefficient (ICC). We assessed the correlation between the risk-adjusted mean number of surgical procedures and risk-adjusted incidence of mortality and complications using Pearson correlation coefficients (r). RESULTS: Moderate inter-hospital variation was observed for orthopaedic surgery (ICC = 14.0%) whereas variation was low for torso surgery (ICC = 2.7%) and neurosurgery (ICC = 0.8%). Surgical intensity was negatively correlated with hospital mortality for torso injury (r = -.32, P = .02) and neurotrauma (r = -.65, P = .08). A strong positive correlation was observed with hospital complications for orthopaedic injuries (r = .36, P = .006) whereas the opposite was observed for neurotrauma (r = -.71, P = .05). CONCLUSIONS: Results should be interpreted with caution as they may be a result of residual confounding. However, they may suggest that there are opportunities for quality improvement in surgical care for injury admissions, particularly for orthopaedic injuries. Moving forward, we should aim to prospectively evaluate adherence to guidelines on non-operative management and their impact on mortality and morbidity.

Resource use for older people hospitalised due to injury in a Canadian integrated trauma system: a retrospective multicenter cohort study.

BACKGROUND: Injuries represent one of the leading causes of preventable morbidity and mortality. For countries with ageing populations, admissions of injured older patients are increasing exponentially. Yet, we know little about hospital resource use for injured older patients. Our primary objective was to evaluate inter-hospital variation in the risk-adjusted resource use for injured older patients. Secondary objectives were to identify the determinants of resource use and evaluate its association with clinical outcomes. METHODS: We conducted a multicenter retrospective cohort study of injured older patients (≥65 years) admitted to any trauma centres in the province of Quebec (2013-2016, N = 33,184). Resource use was estimated using activity-based costing and modelled with multilevel linear models. We conducted separate subgroup analyses for patients with trauma and fragility fractures. RESULTS: Risk-adjusted resource use varied significantly across trauma centres, more for older patients with fragility fractures (intra-class correlation coefficients [ICC] = 0.093, 95% CI [0.079, 0.102]) than with trauma (ICC = 0.047, 95% CI = 0.035-0.051). Risk-adjusted resource use increased with age, and the number of comorbidities, and varied with discharge destination (P < 0.001). Higher hospital resource use was associated with higher incidence of complications for trauma (Pearson correlation coefficient [r] = 0.5, 95% CI = 0.3-0.7) and fragility fractures (r = 0.5, 95% CI = 0.3-0.7) and with higher mortality for fragility fractures (r = 0.4, 95% CI = 0.2-0.6). CONCLUSIONS: We observed significant inter-hospital variations in resource use for injured older patients. Hospitals with higher resource use did not have better clinical outcomes. Hospital resource use may not always positively impact patient care and outcomes. Future studies should evaluate mechanisms, by which hospital resource use impacts care.

Hip-Knee-Ankle (HKA) angle modification during gait in healthy subjects.

BACKGROUND: Achieving a neutral static Hip-Knee-Ankle angle (sHKA) measured on radiographs has been considered a factor of success for total knee arthroplasty (TKA). However, recent studies have shown that sHKA seems to have no effect on TKA survivorship. sHKA is not representative of the dynamic loading occurring during gait, unlike the dynamic HKA (dHKA). RESEARCH QUESTION: The primary objective was to see if the sHKA is predictive of the dynamic HKA (dHKA). A secondary objective was to document to what degree the dHKA changes during gait. METHODS: We analysed 3D knee kinematics during gait of a cohort of 90 healthy individuals with the KneeKG™ system. dHKA was calculated and compared with sHKA. Knees were considered "Stable" if the dHKA remained in valgus or varus for greater than 95% of the corresponding phase, and "Changer" otherwise. Patient characteristics of the Stable and Changer knees were compared to find associated factors. RESULTS: Absolute variation of dHKA during gait was 10.9 ± 5.3° for the whole cohort. The variation was less for the varus knees (10.3 ± 4.8°), than for the valgus knees (12.8 ± 6.1°, p = 0.008). We found low to moderate correlations (r = 0.266 to 0.553, p < 0.001) between sHKA and dHKA values for varus knees and no significant correlation for valgus knees. Twenty two percent (36/165) of the knees were considered Changers. The proportion of knees that were Changers was 15% of the varus versus 39% of the valgus (p < 0.001). SIGNIFICANCE: Lower limb radiographic measures of coronal alignment have limited value for predicting dynamic measures of alignment during gait.

Patient-level resource use for injury admissions in Canada: A multicentre retrospective cohort study.

BACKGROUND: Variations in adjusted costs have been observed among trauma centres in the United States but patient outcomes were not better in centres with higher costs. Attempts to improve injury care efficiency are hampered by insufficient patient-level information on resource use and on the drivers of resource use intensity. OBJECTIVES: To estimate patient-level resource use for injury admissions, identify determinants of resource use intensity, and evaluate inter-hospital variations in resource use. METHODS: We conducted a retrospective cohort study including ≥16-year-olds admitted to adult trauma centres in a mature, inclusive Canadian trauma system between 2014 and 2016. We extracted data from the trauma registry and hospital financial reports. We estimated resource use with activity-based costs, identified determinants of resource use intensity using a multilevel linear model and assessed the relative importance of each determinant with Cohen's f2. We evaluated inter-provider variations with intraclass correlation coefficients (ICC) and 95% confidence intervals. RESULTS: We included 32,411 patients. Median costs per admission were $4857 (Quartiles 1 and 3 2961-8448). The most important contributors to total resource use were the medical ward (57%), followed by the operating room (OR; 23%) and the intensive care unit (13%). The strongest determinant of resource use intensity was discharge destination (Cohen's f2 = 7%). The most resource intense patient group was spinal cord injuries with $11,193 (7115-17,606) per admission. While resource use increased with increasing age for the medical ward, it decreased with increasing age for the OR. Resource use was 18% higher in level I centres compared to level IV centres and we observed significant variations in resource use across centres (ICC = 5% [4-6]), particularly for the OR (28% [20-40]). CONCLUSIONS: Resource use for acute injury care in Quebec is not solely due to the clinical status of patients. We identified determinants of resource use that can be used to establish evidence-based resource allocations and improve injury care efficiency. The method we developed for estimating patient-level, in-hospital resource use for injury admissions and identifying related determinants could be reproduced using local trauma registry data and our unit costs or unit costs specific to each setting.

Kinematic alignment in total knee arthroplasty better reproduces normal gait than mechanical alignment.

PURPOSE: Kinematic alignment technique for TKA aims to restore the individual knee anatomy and ligament tension, to restore native knee kinematics. The aim of this study was to compare parameters of kinematics during gait (knee flexion-extension, adduction-abduction, internal-external tibial rotation and walking speed) of TKA patients operated by either kinematic alignment or mechanical alignment technique with a group of healthy controls. The hypothesis was that the kinematic parameters of kinematically aligned TKAs would more closely resemble that of healthy controls than mechanically aligned TKAs. METHODS: This was a retrospective case-control study. Eighteen kinematically aligned TKAs were matched by gender, age, operating surgeon and prosthesis to 18 mechanically aligned TKAs. Post-operative 3D knee kinematics analysis, performed with an optoelectronic knee assessment device (KneeKG®), was compared between mechanical alignment TKA patients, kinematic alignment TKA patients and healthy controls. Radiographic measures and clinical scores were also compared between the two TKA groups. RESULTS: The kinematic alignment group showed no significant knee kinematic differences compared to healthy knees in sagittal plane range of motion, maximum flexion, abduction-adduction curves or knee external tibial rotation. Conversely, the mechanical alignment group displayed several significant knee kinematic differences to the healthy group: less sagittal plane range of motion (49.1° vs. 54.0°, p = 0.020), decreased maximum flexion (52.3° vs. 57.5°, p = 0.002), increased adduction angle (2.0-7.5° vs. - 2.8-3.0°, p < 0.05), and increased external tibial rotation (by a mean of 2.3 ± 0.7°, p < 0.001). The post-operative KOOS score was significantly higher in the kinematic alignment group compared to the mechanical alignment group (74.2 vs. 60.7, p = 0.034). CONCLUSIONS: The knee kinematics of patients with kinematically aligned TKAs more closely resembled that of normal healthy controls than that of patients with mechanically aligned TKAs. This may be the result of a better restoration of the individual's knee anatomy and ligament tension. A return to normal gait parameters post-TKA will lead to improved clinical outcomes and greater patient satisfaction. LEVEL OF EVIDENCE: III.

Healthy 3D knee kinematics during gait: Differences between women and men, and correlation with x-ray alignment.

BACKGROUND: Normal 3D knee kinematics during gait is still not well understood, especially regarding differences between women and men. RESEARCH QUESTION: The objective of the present study was to characterize 3D knee kinematics during gait in healthy women and men with a validated tool. METHODS: Knee kinematics was analysed with the KneeKG™ system in 90 healthy subjects (49 females and 41 males). 3D knee rotations were compared between women and men, and between right and left knees. Each subject underwent full-length weight-bearing x-rays. Correlations between abduction-adduction angles and lower-limb alignment measures on x-rays were assessed. RESULTS: In the frontal plane, 2.0-5.0° more abduction occurred in women compared to men (0.000 ≤ p ≤ 0.015) throughout the entire gait cycle. In the transverse plane, 2.4-3.7° more external tibial rotation was seen in women than in men (0.002 ≤ p ≤ 0.041) during the initial and mid-swing phases. No difference was found between the right and left knees. Low correlations (-0.52 ≤ r≤-0.41, p < 0.001) were observed between radiographic hip-knee-ankle angle (HKA) and abduction-adduction angles throughout the stance phase. SIGNIFICANCE: Kinematic differences between women and men in the frontal plane can be partly explained by their anatomical differences: women were less in varus than men (HKA of -0.8° vs. -2.6°, p < 0.001). Our study contributes to a better understanding of healthy 3D knee kinematics during gait and highlights the need for accounting of gender differences in future investigations. Better knowledge of natural knee kinematics will be helpful in assessing pathological gait patterns or determining the efficiency of conservative and surgical treatments to restore normal kinematics.

Comparison of soft tissue artifact and its effects on knee kinematics between non-obese and obese subjects performing a squatting activity recorded using an exoskeleton.

BACKGROUND: Rigid attachment systems are one of the methods used to compensate for soft tissue artifact (STA) inherent in joint motion analyses. RESEARCH QUESTION: The goal of this study was to quantify STA of an exoskeleton design to reduce STA at the knee, and to assess the accuracy of 3D knee kinematics recorded with the exoskeleton in non-obese and obese subjects during quasi-static weight-bearing squatting activity using biplane radiography. METHODS: Nine non-obese and eight obese subjects were recruited. The exoskeleton was calibrated on each subject before they performed a quasistatic squatting activity in the EOS® imaging system. 3D models of exoskeleton markers and knee bones were reconstructed from EOS® radiographs; they served to quantify STA and to evaluate differences between the markers and bones knee kinematics during the squatting activity. RESULTS: The results showed that STA observed at the femur was larger in non-obese subjects than in obese subjects in frontal rotation (p = 0.004), axial rotation (p = 0.000), medio-lateral displacement (p = 0.000) and antero-posterior displacement (p = 0.019), while STA observed at the tibia was lower in non-obese subjects than in obese subjects for the three rotations (p < 0.05) and medio-lateral displacement (p = 0.015). Differences between the markers and bones knee kinematics increased with knee flexion and were similar in both groups, except for abduction-adduction: 4.9° for non-obese subjects against 2.3° for obese subjects (p = 0.011). SIGNIFICANCE: This study demonstrated that STA at the femur and its impact on knee abduction-adduction using a specific exoskeleton were greater among non-obese subjects than obese subjects, which is encouraging for future biomechanical studies on pathologies such as osteoarthritis.