Introduction The coronavirus lockdown in 2020 resulted in a worldwide suspension of professional sports. The first major professional football league to restart after the lockdown was the German Bundesliga. This study investigates whether the injury incidence increased after the restart of the season with only 9 days of regular preparation time and without any friendly matches in comparison to three control periods. Materials and methods In a prospective cohort study, injury analysis (at least 1 day of absence from official football matches or training sessions) of the German Bundesliga registry was standardised according to Hägglund et al. (Br J Sports Med 39:340–346, 2005) and Fuller et al. (Clin J Sports Med 16:97–106, 2006) for data collection and to previous publications for the validated use of media sources for injury registration. The study period after the lockdown in May and June of the 2019–2020 season was compared to three control periods: the period directly before the lockdown, the beginning of the 2019–2020 season and the 2018–2019 season final. Results The nine match days after the restart of the 2019–2020 season showed an overall injury incidence of 4.9 per 1000 h football. This rate was significantly lower than that of the previous season final (9 last match days, overall injury incidence: 6.9 per 1000 h football; p < 0.001) and not increased compared to the rates after the summer break (9 match days; incidence: 5.5/1000 h, p > 0.05) or the winter break (8 match days; incidence: 5.6/1000 h, p > 0.05). Conclusion The period after the unexpected break in the 2019–2020 season due to the coronavirus lockdown and the rapid return to competition showed no increase in the injury rate compared to the pre-lockdown period and a lower injury rate than in the previous season final. The unintentional mid-season rest with its potential for physical recovery and individual fitness training seems to have had a positive effect on injury occurrence.

Purpose ACL injuries are one of the most severe injuries in football, but medical consequences and performance outcomes after return to competition are only rarely investigated. Aim of this study was to analyse the time of return to competition (RTC) in German professional, semi-professional and amateur football. Also, this investigation highlights the rate of career ending and performance outcome after RTC in different playing levels by the measurement of playing level, performed matches and played minutes. Methods Database of this investigation is the ‘ACL registry in German Football’ with prospectively collected injury data. Between 2014 and 2018, four seasons in professional (1st–3rd league), semi-professional (4th–6th league) and amateur leagues (7th league) were analysed regarding the return to competition period and performance parameters. Data were collected for three subsequent seasons after injury and compared with the pre-injury and injury season. Data collection was performed using standardized methods. Results A total of 607 ACL injuries were registered during the 4-year period with a mean RTC time of 337.1 day (SD: 183). After primary ACL ruptures, the fastest RTC was found in professional football (247.3 days), while in semi-professional (333.5 d; p < 0.0001) and amateur football (376.2 d; p < 0.0001) a prolonged absence was detected. Re-ruptures occurred in 17.8% (n = 108) and showed similar trend with fastest RTC in professionals (289.9 days; p = 0.002). Within the first three seasons after injury, 92 players (36.7%) in semi-professional and 24 (20%) in professionals had to end their career. Keeping the level of play was only possible for 48 (47.5%) of professionals, while only 47 (29.6%) of semi-professionals and 43 (28.1%) of amateurs were able to. Only in professional football, no significant difference could be seen in the played minutes and games after 2 years compared to the pre-injury season. Conclusion Lower playing levels and re-ruptures are the main factors for a prolonged return to competition after ACL rupture in German football. Significant reduction in playing level and a high rate of career endings were found for all levels of play. However, only professional players were able to regain their playing minutes and games 2 years after injury, while lower classed athletes did not reach the same amount within 3 years. Level of evidence Level III.

Purpose Anterior cruciate ligament (ACL) injuries are a common severe type of football injury at all levels of play. A football-specific ACL registry providing both prospective ACL injury data according to the skill level and risk factors for ACL injury is lacking in the literature. Methods This study is based on the prospective ‘ACL registry in German Football’ implemented in the 2014–15 season. Professional (1st–3rd league), semi-professional (4th–6th league) and amateur leagues (7th league) were analysed regarding the incidence and risk factors for ACL injuries. Injuries were registered according to the direct reports of the injured players to the study office and double-checked via media analysis. After injury registration, the players received a standardised questionnaire. Data were analysed from the 2014–15 to the 2018–19 football season. Results Overall, 958 ACL injuries were registered during the 5-year study period. The incidence of ACL injuries was highest in amateur football (0.074/1000 h football exposure) compared to professional (0.058/1000 h; p < 0.0001) and semi-professional football (0.043/1000 h; p < 0.0001). At all skill levels, match incidence (professional: 0.343; semi-professional: 0.249; amateur: 0.319) was significantly higher than training incidence (professional: 0.015; semi-professional: 0.004; amateur: 0.005). Major risk factors were previous ACL injury (mean: 23.3%), other knee injuries (mean: 19.3%) and move to a higher league (mean: 24.2%). Conclusion This sports-specific ACL registry provides detailed information on the incidence and risk factors for ACL injuries in football over five years. Risk factors are skill level, match exposure, move to a higher league and previous knee injury. These factors offer potential starting points for screening at-risk players and applying targeted prevention. Level of evidence II.

Introduction Intracapsular femoral neck fractures are one of the most common fractures in Germany. Nevertheless, the epidemiology and treatment modalities are not described comprehensively. For this reason, this study highlights the epidemiology of femoral neck fractures in different age groups and summarizes treatment strategies within the period from 2009 to 2019 based on nationwide data. Materials and methods In this retrospective cohort study all cases of intracapsular femoral neck fractures (ICD-10: S72.0) between 2009 and 2019 in Germany were analyzed with regard to epidemiology, incidence and treatment. Operation and procedure classification system (OPS)- codes in combination with intracapsular femoral neck fracture as main diagnosis were taken to investigation. Data was provided by the Federal Statistical Office of Germany (Destatis). Results A total of 807,834 intracapsular femoral neck fractures with a mean incidence of 110.0 per 100,000 inhabitants annually was detected within eleven years. In 68.8% of all fractures patients were female. Most patients were older than 70 years (82.4%), and 56.7% were older than 80 years. The overall increase of fracture numbers between 2009 and 2019 was 23.2%. Joint replacement has been most often performed (80.4%). Hemiarthroplasty (56.8%) and total hip arthroplasty (22.8%) were the most common procedures with an increase of 27.1 and 38.6%, respectively. The proportion of cemented hemiarthroplasties was 86.2% while 51.3% of all total hip arthroplasties were totally or partially cemented. Osteosyntheses were mainly conducted using dynamic compression screws (34.0%), conventional screws (31.3%) and nails (22.2%). Conclusion The incidence of intracapsular femoral neck fractures in Germany has been increasing continuously within the last decade. In particular, patients over 80 years suffered predominantly from this type of fracture. The majority was treated with a joint replacement procedure, mainly cemented hemiarthroplasty.

Introduction Football is the most popular sport worldwide and results in a high frequency of injuries. So far, mainly injuries in professional football have been investigated, and the literature lacks data regarding detailed injury epidemiology and current prevention data in amateur football tournaments. Materials and methods A prospective cohort study investigated an international amateur football tournament, the UEFA Regions’ Cup, which took place in 2019 in Germany. Injury epidemiology, current prevention strategies of the teams and the implementation of the UEFA concussion protocol were investigated in detail by means of standardized injury definitions and data samples for football (Fuller et al., Scand J Med Sci Sports 16:83–92, https://doi.org/10.1111/j.1600-0838.2006.00528.x, 2006). Results 138 player of 8 teams participated in this study, while 39 players were excluded. Overall injury incidence was 12.5 per 1000 h total football exposure, 43.5 per 1000 h for match exposure. No injuries were registered during training. Injury prevalence was 14.1% per player and 1.1 injuries per match were registered. The lower extremity was predominantly affected by injuries (71.4%) and the majority of injuries (78.6%) were non-severe injury types like contusions (50%) and sprains (18.2%). Two head injuries, one contusion and one skin lesion, were handled by the guidelines of the UEFA concussion protocol. 44.4% of the players indicated at least one previous injury before tournament, 45.3% of them during the last two football seasons before start of the tournament. Injury prevention performance was included in all participating teams during the tournament by warm up or training strategies (100%). During the warm-up program just 5 exercises of the FIFA 11 + program was detected by this investigation in participating teams to be done by more half of the teams. Running exercises were the most frequently performed exercises, while trunk muscle exercises were less represented (14.3%). Conclusion This study presents for the first time epidemiological injury and prevention data of the UEFA Regions Cup. Injury incidence was higher compared to injury reports of regular seasons, but lower compared to other amateur football tournaments. Currently used prevention programs revealed trunk muscle exercises as often neglected.