Do changes in middle-distance running kinematics contribute to the age-related decline in performance?

OBJECTIVES:The aim of this study was to assess ageing-related changes in middle-distance running kinematics and performance in master athletes. METHODS:Male athletes (n=157; 57±13.3 years) competing in the 800- and 1500-m runs at the German Master Athletics Outdoor Championships 2018 were filmed and the bending-over angle, brake angle, leg-stiffness angle, propulsion angle and hip-flexion angle measured. RESULTS:Leg-stiffness and propulsion angle decreased with age (all p<.001), while bending-over, brake and hip-flexion angle increased (all p<.001). Bending-over, propulsion and hip-flexion angles were smaller in 800- than 1500-m races, while the brake angle was larger in 800- than 1500-m races (all p<.001), with no significant difference in leg-stiffness angle between disciplines. In the last round, hip flexion was lower compared to earlier rounds in both distances (p<.001). Age was the major predictor for performance in both races (800-m Radj2=0.74; p<.001, 1500-m Radj2=0.80; p<.001), with a minor impact of technique (improved Radj2 to 0.84 and 0.86, respectively). CONCLUSIONS:The study revealed that the ageing-related decline in running performance of master athletes was primarily explicable by age with only a small contribution of changes in sprint kinematics

Experimental Trauma Models: An Update

Treatment of polytrauma patients remains a medical as well as socioeconomic challenge. Although diagnostics and therapy improved during the last decades, multiple injuries are still the major cause of fatalities in patients below 45 years of age. Organ dysfunction and organ failure are major complications in patients with major injuries and contribute to mortality during the clinical course. Profound understanding of the systemic pathophysiological response is crucial for innovative therapeutic approaches. Therefore, experimental studies in various animal models are necessary. This review is aimed at providing detailed information of common trauma models in small as well as in large animals

Single versus double bundle in posterior cruciate ligament (PCL) reconstruction: a meta-analysis

Posterior cruciate ligament (PCL) reconstruction can be performed using single bundle (SB) and double bundle (DB) techniques. The present study investigated whether DB PCL reconstruction is superior to SB reconstruction in terms of patient reported outcome measures (PROMs) and joint stability. In December 2021 Embase, Google Scholar, Pubmed, Scopus databases were accessed. All clinical trials comparing SB versus DB reconstruction to address PCL insufficiency in skeletally mature patients were considered. Data from 483 procedures were retrieved. The mean follow-up was 31.0 (28.0 to 107.6) months, and the mean timespan between injury and surgery was 11.3 (6 to 37) months. The mean age of the patients was 29.3 ± 3.8&nbsp;years. 85 of 483 patients (18%) were women. At a mean of 31.0&nbsp;months post reconstruction, ROM (P = 0.03) was slightly greater in the SB group, while the Tegner score (P = 0.03) and the Telos stress (P = 0.04) were more favorable in the DB cohort. Similarity was found in instrumental laxity (P = 0.4) and Lysholm score (P = 0.3). The current evidence does not support the use of DB techniques for PCL reconstruction. Both methods could restore knee stability and motion with satisfactory short term patient reported outcome measures. Further high quality clinical trials are required to validate these results on a larger scale

Outcomes and complications of the reamer irrigator aspirator versus traditional iliac crest bone graft harvesting: a systematic review and meta-analysis

Background The reamer irrigator aspirator (RIA) is a relatively recent device that is placed in the medullary canal of long bones to harvest a large volume of bone marrow, which is collected in a filtered canister. This study compares outcomes and complications of the RIA versus a traditional iliac crest bone graft (ICBG) for the treatment of bone defects. Methods This meta-analysis was conducted according to the PRISMA guidelines. The Embase, Google Scholar, PubMed, and Scopus databases were accessed in June 2021. All clinical trials comparing the RIA and ICBG with a minimum of 6 months follow-up were included. Results Data from 4819 patients were collected. The RIA group demonstrated lower site pain (P &lt; 0.0001), fewer infections (P = 0.001), and a lower rate of adverse events (P &lt; 0.0001). The ICBG group demonstrated a greater rate of bone union (P &lt; 0.0001). There was no difference between groups in VAS (P = 0.09) and mean time to union (P = 0.06). Conclusion The current evidence supports the use of the RIA, given its low morbidity and short learning curve

Platelet-rich plasma (PRP) augmentation does not result in more favourable outcomes in arthroscopic meniscal repair: a meta-analysis

Background The efficacy and safety of platelet-rich plasma (PRP) augmentation for arthroscopic meniscal repair is controversial. This meta-analysis compared arthroscopic meniscal repair performed in isolation or augmented with PRP. Methods The present study was conducted according to PRISMA 2020 guidelines. Pubmed, Web of Science, Google Scholar and Embase were accessed in August 2021. All the clinical trials which compared arthroscopic meniscal repair performed in isolation or augmented with PRP were included. Results Eight hundred thirty-seven patients were included: 38% (318 of 837 patients) were women; the mean age of the patients was 35.6 (range, 20.8-64.3) years; the mean follow-up was 26.2 (range, 6-54) months. Similarity was found in analogue scale (VAS) (P = 0.5) and Lysholm (P = 0.9), and International Knee Documentation Committee (IKDC) scores (P = 0.9). Similarity was found in the rate of failure (P = 0.4) and rate of revision (P = 0.07). Conclusion The current published scientific evidence does not support PRP augmentation for arthroscopic meniscal repair

Chondral injuries in patients with recurrent patellar dislocation: a systematic review

Background Patellar dislocations in patients presenting with recurrent patellofemoral instability can damage the surrounding structures, limiting patient's participation to recreational activities and quality of life. This study evaluated frequency, location, and extent of associated injuries in patients with recurrent patellar dislocation. Methods This systematic review was conducted according to the PRISMA checklist. PubMed, Google scholar, Embase, and Web of Science databases were accessed in July 2021. All the published clinical studies reporting frequency, location, and extent of soft tissue lesions in patients with recurrent patellar dislocations were accessed. Results Data from 9 articles (232 patients) were retrieved. The mean age of the included patients was 21.2 +/- 5.6 years. 84.8% of patients suffering from recurrent patellar dislocations demonstrated patellar chondral defects: medial facet (34.9%), while patellar crest (34.8%) and lateral facet (17%). 27.8% of patients demonstrated trochlear chondral injuries. Conclusion Chondral defects of the medial facet and the crest of the patella are the most common in patients with recurrent patellofemoral instability

Funding Era Free Speech Theory: Applying Traditional Speech Protection to the Regulation of Anonymous Cyberspace

Abstract Background Blunt trauma is the most frequent mechanism of injury in multiple trauma, commonly resulting from road traffic collisions or falls. Two of the most frequent injuries in patients with multiple trauma are chest trauma and extremity fracture. Several trauma mouse models combine chest trauma and head injury, but no trauma mouse model to date includes the combination of long bone fractures and chest trauma. Outcome is essentially determined by the combination of these injuries. In this study, we attempted to establish a reproducible novel multiple trauma model in mice that combines blunt trauma, major injuries and simple practicability. Methods Ninety-six male C57BL/6 N mice (n = 8/group) were subjected to trauma for isolated femur fracture and a combination of femur fracture and chest injury. Serum samples of mice were obtained by heart puncture at defined time points of 0 h (hour), 6 h, 12 h, 24 h, 3 d (days), and 7 d. Results A tendency toward reduced weight and temperature was observed at 24 h after chest trauma and femur fracture. Blood analyses revealed a decrease in hemoglobin during the first 24 h after trauma. Some animals were killed by heart puncture immediately after chest contusion; these animals showed the most severe lung contusion and hemorrhage. The extent of structural lung injury varied in different mice but was evident in all animals. Representative H&E-stained (Haematoxylin and Eosin-stained) paraffin lung sections of mice with multiple trauma revealed hemorrhage and an inflammatory immune response. Plasma samples of mice with chest trauma and femur fracture showed an up-regulation of IL-1β (Interleukin-1β), IL-6, IL-10, IL-12p70 and TNF-α (Tumor necrosis factor- α) compared with the control group. Mice with femur fracture and chest trauma showed a significant up-regulation of IL-6 compared to group with isolated femur fracture. Conclusions The multiple trauma mouse model comprising chest trauma and femur fracture enables many analogies to clinical cases of multiple trauma in humans and demonstrates associated characteristic clinical and pathophysiological changes. This model is easy to perform, is economical and can be used for further research examining specific immunological questions

Operative Management of Avascular Necrosis of the Femoral Head in Skeletally Immature Patients: A Systematic Review

Purpose: Osteonecrosis of the femoral head (ONFH) is common in skeletally immature patients. The management of ONFH is controversial, with limited evidence and unpredictable results. This study systematically reviewed the current operative modalities and clinical outcomes of surgical management for ONFH in skeletally immature patients. Methods: The present study was conducted according to the PRISMA 2020 guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in October 2021. All the published clinical studies reporting data concerning the surgical management of ONFH in skeletally immature patients were included. Results: This review included 122 patients (127 hips). 38.2% (46 of 122) were female. The mean age of the patients was 14.2 +/- 2.3 years. The mean duration of the follow-up was 55.3 +/- 19.6 months. The Harris Hip Score improved from 68.8 +/- 11.9 at baseline to 90.5 +/- 6.5 at last follow-up (p &lt; 0.0001). Femoral head collapse and secondary hip degeneration were the most common complications. Conclusion: Several surgical techniques are available and effective for the management of ONFH in skeletally immature patients. This study evidenced high heterogeneity of the surgical procedures and eligibility criteria. Further high-quality investigations are required to establish proper indications and surgical modalities

NUMERISCHES MODELL FÜR DIE SIMULATION EINER LASERSTRAHLSCHWEIßUNG VON QUARZGLAS

Ausgehend von den fundierten Erfahrungen, die für das Schweißen von verschiedensten Metallen vorliegen, wird an der Professur Stahlbau der Bauhaus-Universität Weimar ein neuartiges Verfahren zum CO2-Laserstrahlschweißen von Quarzglas numerisch untersucht. Dabei kommt die kommerzielle FE-Software SYSWELD® zum Einsatz. Die erforderlichen Versuche werden in Zusammenarbeit mit dem Institut für Fügetechnik und Werkstoffprüfung GmbH aus Jena realisiert. Die numerische Analyse wird eingesetzt, um geeignete Prozessparameter zu bestimmen und deren Auswirkungen auf die transienten thermischen und mechanischen Vorgänge, die während des Schweißvorgangs ablaufen abzubilden. Um die aus der Simulation erhaltenen Aussagen zu überprüfen, ist es erforderlich, das Berechnungsmodell mittels Daten aus Versuchsschweißungen zu kalibrieren. Dabei sind die verwendeten Materialmodelle sowie die der Simulation zugrunde gelegten Materialkennwerte zu validieren. Es stehen verschiedene rheologische Berechnungsmodelle zur Auswahl, die die viskosen Materialeigenschaften des Glases abbilden. Dabei werden die drei mechanischen Grundelemente, die HOOKEsche Feder, der NEWTONsche Dämpfungszylinder und das ST.-VENANT-Element miteinander kombiniert. Die Möglichkeit, thermische und mechanische Vorgänge innerhalb des Glases während des Schweißvorgangs und nach vollständiger Abkühlung, vorhersagen zu können, gestattet es den Schweißvorgang über eine Optimierung der Verfahrensparameter gezielt dahingehend zu beeinflussen, die Wirtschaftlichkeit des Schweißverfahrens zu verbessern, und ein zuverlässiges Schweißergebnis zu erhalten. Dabei können auch nur unter hohem experimentellen Aufwand durchführbare Versuche simuliert werden, um eine Vorhersage zu treffen, ob es zweckmäßig ist, den Versuch auch in der Praxis zu fahren. Dies führt zu einer Reduzierung des experimentellen Aufwandes und damit zu einer Verkürzung des Entwicklungszeitraumes für das angestrebte Verfahren