Hypothesized mechanisms of death in swimming: a systematic review.

BACKGROUND: The study aims to update the specific classification of mechanisms of death in swimming and to demonstrate these categories are reasonable, by analyzing more characteristics of death cases, evaluating the available evidence and determining their quality. METHODS: Original articles were queried from PubMed, Web of Science, Embase databases, Cochrane Library, and Scopus. Included studies, which were evaluated as level 4 evidence or higher according to the Oxford Centre for Evidence-Based Medicine, discussed hypothesized mechanisms of death in swimming. Parameters analyzed in this study included decedents' characteristics, outcome measures, findings, methodological index for non-randomized studies (MINORS), and critical evaluation of each study classified by death mechanism. RESULTS: A total of twenty-five studies were included for further analysis: fourteen were associated with cardiovascular diseases, two were about cerebrovascular diseases, two contained respiratory diseases, seven were about hazardous conditions and three contained other drownings, which provided evidence for mechanisms of death. CONCLUSIONS: It is found that cardiovascular disease is the main cause or contributing factor of death in swimming. Respiratory diseases and cerebrovascular diseases are difficult to be definitive mechanism categories due to insufficient evidence. Hazardous conditions appear to be one of the possible risk factors because there are more cases of deaths from unsafe environments in swimming, but further statistics and research are still needed to support this view. Our study may have important implications for developing potential prevention strategies for sports and exercise medicine. TRIAL REGISTRATION: PROSPERO ID (CRD42021267330). Registered Aug 13th 2021.

The Effect of Lateral Extra-articular Tenodesis in an ACL-Reconstructed Knee With Partial Medial Meniscectomy: A Biomechanical Study.

BACKGROUND: Knee laxity increases with medial meniscectomy in anterior cruciate ligament (ACL)-reconstructed knees; however, the biomechanical effect of an additional lateral extra-articular tenodesis (LET) is unknown. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the kinematic effect of a LET in knees that underwent combined ACL reconstruction (ACL-R) and partial medial meniscus posterior horn (MMPH) meniscectomy. It was hypothesized that the addition of LET would reduce laxity in the ACL-reconstructed knee. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen human cadaveric knees (mean age, 41.5 years) were tested using a robotic system under 3 loads: (1) 89.0 N of anterior tibial (AT) load, (2) 5 N·m of internal rotation (IR) tibial torque, and (3) a simulated pivot shift-a combined valgus of 7 N·m and IR torque of 5 N·m-at 0°, 15°, 30°, 45°, 60°, and 90° of knee flexion. Kinematic data were acquired in 4 states: (1) intact, (2) ACL-R, (3) ACL-R + partial MMPH meniscectomy (MMPH), and (4) ACL-R + partial MMPH meniscectomy + LET (MMPH+LET). RESULTS: In response to AT loading, there was a significant increase seen in AT translation (ATT) in the MMPH state at all knee flexion angles compared with the ACL-R state, with the highest increase at 90° of knee flexion (mean difference, 3.1 mm) (P < .001). Although there was a significant decrease in ATT at 15° of knee flexion with MMPH+LET (P = .022), no significant differences were found at other knee flexion angles (P > .05). In MMPH with IR torque, a significant increase was observed in IR at all knee flexion angles except 90° compared with the ACL-R state (range, 2.8°-4.9°), and this increase was significantly decreased at all flexion angles with the addition of LET (range, 0.7°-1.6°) (P < .05). CONCLUSION: Performing a partial MMPH meniscectomy increased ATT and IR in response to AT and IR loads compared with the isolated ACL-R state in a cadaveric model. However, when the LET procedure was performed after partial MMPH meniscectomy, a significant decrease was seen at all knee flexion angles except 90° in response to IR and torque, and a significant decrease was seen at 15° of knee flexion in response to AT load. CLINICAL RELEVANCE: LET may be a useful adjunct procedure after ACL-R with partial MMPH meniscectomy to reduce knee laxity.

Augmenting ACL Repair With Suture Tape Improves Knee Laxity: A Biomechanical Study.

Background: Anterior cruciate ligament (ACL) repair is an alternative to reconstruction; however, suture tape support may be necessary to achieve adequate outcomes. Purposes: To investigate the influence of suture tape augmentation (STA) of proximal ACL repair on knee kinematics and to evaluate the effect of the 2 flexion angles of suture tape fixation. Study Design: Controlled laboratory study. Methods: Fourteen cadaveric knees were tested using a 6 degrees of freedom robotic testing system under anterior tibial (AT) load, simulated pivot-shift (PS) load, and internal rotation (IR) and external rotation loads. Kinematics and in situ tissue forces were evaluated. Knee states tested were (1) ACL intact, (2) ACL cut, (3) ACL repair with suture only, (4) ACL repair with STA fixed at 0° of knee flexion, and (5) ACL repair with STA fixed at 20° of knee flexion. Results: ACL repair alone did not restore the intact ACL AT translation at 0°, 15°, 30°, or 60° of flexion. Adding suture tape to the repair significantly decreased AT translation at 0°, 15°, and 30° of knee flexion but not to the level of the intact ACL. With PS and IR loadings, only ACL repair with STA fixed at 20° of flexion was not significantly different from the intact state at all knee flexion angles. ACL suture repair had significantly lower in situ forces than the intact ACL with AT, PS, and IR loadings. With AT, PS, and IR loadings, adding suture tape significantly increased the in situ force in the repaired ACL at all knee flexion angles to become closer to that of the intact ACL state. Conclusion: For complete proximal ACL tears, suture repair alone did not restore normal knee laxity or normal ACL in situ force. However, adding suture tape to augment the repair resulted in knee laxity closer to that of the intact ACL. STA with fixation at 20° of knee flexion was superior to fixation with the knee in full extension. Clinical Relevance: The study findings suggest that ACL repair with STA fixed at 20° could be considered in the treatment of femoral sided ACL tears in the appropriate patient population.

Arthroscopic centralization reduces extrusion of the medial meniscus with posterior root defect in the ACL reconstructed knee.

PURPOSE: The purpose of this study was to evaluate the effects of arthroscopic meniscal centralization reinforcement for a medial meniscus (MM) posterior root defect on knee kinematics and meniscal extrusion in the anterior cruciate ligament reconstructed (ACLR) knee. The hypothesis was that the medial meniscus centralization would reduce extrusion and anterior laxity in ACLR knee with a medical meniscal defect. METHODS: Fourteen fresh-frozen human cadaveric knees were tested using a six-degrees-of-freedom robotic system under the following loading conditions: (a) an 89.0 N anterior tibial load, (b) 5.0 Nm internal and external rotational torques, (c) a 10.0 Nm valgus and varus loadings, and (d) a combined 7.0 Nm valgus moment and then a 5.0 Nm internal rotation torque as a static simulated pivot shift. The tested knee states included: (1) anatomic single-bundle cruciate ligament reconstruction with intact medial meniscus (MM Intact), (2) anatomic single-bundle cruciate ligament reconstruction with medial meniscus posterior root defect (MM Defect), (3) Anatomic single-bundle cruciate ligament reconstruction with medial meniscus arthroscopic centralization (MM Centralization). Medial meniscus arthroscopic centralization was performed using 1.4 mm anchors with #2 suture. The MM extrusion (MME) was measured using ultrasound under unloaded and varus loading conditions at 0° and 30° of flexion. RESULTS: Anterior tibial translation (ATT) increased significantly with MM posterior root defect compared to MM intact at all flexion angles. With MM centralization, ATT was not significantly different from the intact meniscus at 15° and 30° of flexion. Meniscus extrusion increased significantly with the root defect compared to intact meniscus and decreased significantly with meniscal centralization compared to the root defect at both flexion angles. CONCLUSIONS: In ACL reconstruction, cases involving irreparable medial meniscal posterior root tears, applying arthroscopic centralization for avoiding the meniscal extrusion should be considered. Clinically, in ACL reconstruction cases with irreparable medial meniscal posterior root tears, applying arthroscopic meniscal centralization for avoiding the meniscal extrusion should be considered. Meniscal centralization decreases the extrusion of the MM and offers improvements in knee laxity.

Effectiveness of "Stop the Bleed" Courses: A Systematic Review and Meta-analysis.

OBJECTIVE: Our object was to comprehensively analyze the existing body of evidence to evaluate the Stop the Bleed (STB) course effectiveness and satisfaction and find the direction of improvement for the future. STUDY DESIGN: A literature search with the term "Stop the Bleed" in the electronic databases PubMed, Web of Science, EMBASE, Cochrane Library was performed, retrieving records from January 1, 2013 to April 13, 2022 based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram. In addition, all selected papers' references were examined for qualified studies that were missed during the first search. Original publications were included that reported on (1) clinical studies of the STB course implementation; and (2) studies comparing students' hemostasis ability and attitude (comfort, confidence, and willingness) before and after the STB course. The literature search and data extraction were done independently by 2 writers. To establish consensus, disagreements will be handled with the help of a third reviewer. For data synthesis, the most inclusive data from studies with repeated data were abstracted. Changes in hemostasis questionnaire scoring and operation evaluation after the STB course were the main outcomes. RESULTS: This systematic review and meta-analysis includes 36 trials with a total of 11,561 trainees. Thirty-one of them were undertaken in the USA, while the other 5, accounting for 13.9%, were conducted in other regions. Among various evaluation methods, 3 trials with 927 trainees indicated that scores of correct uses of tourniquet significantly increased after the STB course (mean difference of post versus pre groups, 44.28; 95% CI 41.24-47.32; p < 0.001). Significant difference was also observed in the willingness to apply a hemostatic dressing in a real-world situation (risk ratio for post versus pre groups, 1.28; 95% CI 1.08-1.52; p = 0.004) (7 studies and 2360 participants). The results indicate that hemostasis knowledge and skills after the STB course had improved, but statistics indicated that STB courses implemented in the USA were more effective than other regions. CONCLUSIONS AND RELEVANCE: Meta-analysis showed that comparison before and after the STB course were significantly different. However, the outcome measures in each study were different and could not, therefore, be compiled in all cases. The effectiveness and worth of implementation of STB in different countries should be continuously evaluated in the future.

No Difference in Knee Kinematics Between Anterior Cruciate Ligament-First and Posterior Cruciate Ligament-First Fixation During Single-Stage Multiligament Knee Reconstruction: A Biomechanical Study.

Background: For combined reconstruction of both the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), there is no consensus regarding which graft should be tensioned and fixed first. Purpose: The purpose of this study was to determine which sequence of graft tensioning and fixation better restores normal knee kinematics. The hypothesis was that ACL-first fixation would more closely restore normal knee kinematics, graft force, and the tibiofemoral orientation in the neutral (resting) position compared with PCL-first fixation. Study Design: Controlled laboratory study. Methods: A total of 15 unpaired human cadaveric knees were examined using a robotic testing system under the following 4 conditions: (1) 89.0-N anterior tibial load at different knee angles; (2) 89.0-N posterior tibial load at different knee angles; (3) combined rotational 7.0-N·m valgus and 5.0-N·m internal rotation load (simulated pivot shift) at 0°, 15°, and 30° of flexion; and (4) 5.0-N·m external rotation load at 0°, 15°, and 30° of flexion. The 4 evaluated knee states were (1) intact ACL and PCL (intact), (2) ACL and PCL deficient (deficient), (3) combined anatomic ACL-PCL reconstruction fixing the ACL first (ACL-first), and (4) combined anatomic ACL-PCL reconstruction fixing the PCL first (PCL-first). A 9.0 mm-diameter quadriceps tendon autograft was used for the ACL graft, tensioned with 40.0 N at 30° of flexion. A 9.5 mm-diameter hamstring tendon autograft (gracilis and semitendinosus, quadrupled loop, and augmented with an additional allograft strand if needed), tensioned with 40.0 N at 90° of flexion, was used for the PCL graft. Results: There were no statistically significant differences between ACL-first and PCL-first fixation regarding knee kinematics. ACL-first fixation restored anterior tibial translation to the intact state at all tested knee angles, while PCL-first fixation showed higher anterior tibial translation than the intact state at 90° of flexion (9.05 ± 3.05 and 5.87 ± 2.40 mm, respectively; P = .018). Neither sequence restored posterior tibial translation to the intact state at 30°, 60°, and 90° of flexion. At 15° of flexion, PCL-first fixation restored posterior tibial translation to the intact state, whereas ACL-first fixation did not. Conclusion: There were no differences in knee laxity between ACL-first and PCL-first fixation with the ACL graft fixed at 30° and the PCL graft fixed at 90°. Clinical Relevance: This study showed that there was no evidence to support the use of one tensioning sequence over the other in single-stage multiligament knee reconstruction.

Comparison of two teaching methods for stopping the bleed: a randomized controlled trial.

BACKGROUND: The "Stop the Bleed" (STB) campaign has achieved remarkable results since it was launched in 2016, but there is no report on the teaching of an STB course combined with a trauma patient simulator. This study proposes the "problem-, team-, and evidence-based learning" (PTEBL) teaching method combined with Caesar (a trauma patient simulator) based on the STB course and compares its effect to that of the traditional teaching method among outstanding doctoral candidates training in haemostasis skills. METHOD: Seventy-eight outstanding doctoral candidate program students in five and eight-year programs were selected as the research subjects and were randomly divided into a control group (traditional teaching method, n = 34) and an experimental group (PTEBL teaching method combined with Caesar, n = 44). Their confidence in their haemostasis skills and willingness to rescue injured victims were investigated before and after the course in both groups. RESULT: Students' self-confidence in their STB skills and the willingness to rescue improved after the class in both groups. Compared with the control group, students in the experimental group were more confident in compressing with bandages and compressing with a tourniquet after a class (compressing with bandages: control group 3.9 ± 0.8 vs. experimental group 4.3 ± 0.7, P = 0.014; compressing with a tourniquet: control group 3.9 ± 0.4 vs. experimental group 4.5 ± 0.8, P = 0.001) More students in the experimental group than the control group thought that the use of Caesar for scenario simulation could improve learning (control group 55.9% vs. experimental group 81.8%, P = 0.024), and using this mannequin led to higher teacher-student interaction (control group 85.3% vs. experimental group 97.7%, P = 0.042). The overall effectiveness of the teaching was better in the experimental group than in the control group (control group 85.3% vs. experimental group 97.7%, P = 0.042). There was a significant positive correlation between teacher-student interactions and the overall effectiveness of teaching (R = 1.000; 95% CI, 1.000-1.000; P < 0.001). CONCLUSION: The PTEBL teaching method combined with Caesar can effectively improve student mastery of STB skills and overcome the shortcomings of traditional teaching methods, which has some promotional value in the training of outstanding doctoral candidates in STB skills.