Injuries in Professional Male Soccer Players in the Netherlands: A Prospective Cohort Study

Context:Injuries are a major adverse event in a soccer player''s career. Reducing injury incidence requires a thorough knowledge of the epidemiology of soccer injuries.Objective:To investigate the incidence and characteristics of injuries in the Dutch premier soccer league.Design:Cohort study.Setting:The Dutch premier soccer league.Results:A total of 286 injuries were recorded, affecting 62.7% of the players. The overall injury incidence was 6.2 injuries per 1000 player-hours, 2.8 in training sessions and 32.8 in matches. Most of the recorded injuries were acute (68.5%). Eight percent of the injuries were classified as recurrent. Injuries were most likely to be located in the lower extremities (82.9%). Injury time loss ranged from 1 to 752 days, with a median of 8 days. Knee injuries had the greatest consequences in terms of days of absence from soccer play (on average, 45 days). The most common diagnosis was muscle/tendon injury of the lower extremities (32.9%).Conclusions:Injury risk in the Dutch premier soccer league is high, especially during matches. Preventive measures should focus on the most common diagnoses, namely, muscle/tendon injuries of the lower extremities.Key Words: football, incidence, epidemiology, elite athletes

Key Points

• Injury risk in the Dutch premier soccer league is high; during 1 season, 62.7% of the players sustained an injury.
• Injuries most often affected the lower extremities (groin, posterior thigh, knee, lower leg/Achilles tendon, and ankle).
• Recurrent injuries caused longer absences than did first-time injuries, and knee injuries had the greatest consequences in time lost from soccer play.
• Preventive measures should focus on the most common diagnoses, namely, muscle/tendon injuries of the lower extremities.

Soccer is the sport with the greatest participation globally.¹ More than 200 million people from 203 nations are members of the Federation of International Football Associations (FIFA), while the Union of European Football Associations (UEFA) has 23 million members in 51 countries.² Outdoor soccer was played by 2635 clubs and approximately 60 500 teams in the Netherlands during the 2011–2012 season. There are currently more than 1.2 million licensed members of the Royal Netherlands Football Association, 45% of whom are adult males.³To obtain a good ranking in competition, soccer players have to be talented, well trained, and healthy, so injuries are a major adverse event in a soccer player''s career. Medical and surgical treatment and rehabilitation interrupt the player''s activity for a period ranging from a few weeks to several months.² If many injuries are sustained, team results can suffer.⁴ Reducing the injury incidence and increasing player safety requires a thorough knowledge of the epidemiology of soccer injuries.⁵ One major problem in the epidemiologic assessment of soccer injuries, however, is the methodologic inconsistency among studies. For example, injury definitions and methods for data collection and recording often differ considerably among studies.^6,7Investigations that describe injury risk and injury patterns in professional soccer have typically been conducted during tournaments,^8–11 have involved only teams at the highest European level,^10,12 have covered only part of a season,¹³ or were related to only 1 team.^14,15 Limited published research has included data on injuries within 1 national professional male soccer competition and involving multiple teams. Hence, little is known about the differences among countries in injury risk and injury patterns in professional male soccer players. During the last 10 years, acute and overuse injuries during matches and training sessions within national professional male soccer competitions have been recorded in Denmark¹³ and Sweden.^16–18 In view of the differences in performance level, medical support, match frequencies, and climate, it is plausible that the incidence and severity of soccer injuries may differ between Scandinavian and other European soccer leagues.¹⁸ Therefore, our study aimed to prospectively record injuries in the Dutch premier soccer league to investigate the incidence and characteristics of injuries in male professional soccer players during 1 entire soccer season.     

Percutaneous radiofrequency ablation for early hepatocellular carcinoma: Risk factors for survival

AIM: To evaluate outcomes of radiofrequency ablation(RFA) therapy for early hepatocellular carcinoma(HCC) and identify survival- and recurrence-related factors. METHODS: Consecutive patients diagnosed with early HCC by computed tomography(CT) or magnetic resonance imaging(MRI)(single nodule of ≤ 5 cm, or multi-(up to 3) nodules of ≤ 3 cm each) and who underwent RFA treatment with curative intent between January 2010 and August 2011 at the Instituto do Cancer do Estado de S o Paulo, Brazil were enrolled in the study. RFA of the liver tumors(with 1.0 cm ablative margin) was carried out under CT-fluoro scan and ultrasonic image guidance of the percutaneous ablation probes. Procedure-related complications were recorded. At 1-mo post-RFA and 3-mo intervals thereafter, CT and MRI were performed to assess outcomes of complete response(absence of enhancing tissue at the tumor site) or incomplete response(enhancing tissue remaining at the tumor site). Overall survival and diseasefree survival rates were estimated by the Kaplan-Meier method and compared by the log rank test or simple Cox regression. The effect of risk factors on survival was assessed by the Cox proportional hazard model. RESULTS: A total of 38 RFA sessions were performed during the study period on 34 patients(age in years: mean, 63 and range, 49-84). The mean follow-up time was 22 mo(range, 1-33). The study population showed predominance of male sex(76%), less severe liver disease(Child-Pugh A, n = 26; Child-Pugh B, n = 8), and single tumor(65%). The maximum tumor diameters ranged from 10 to 50 mm(median, 26 mm). The initial(immediately post-procedure) rate of RFAinduced complete tumor necrosis was 90%. The probability of achieving complete response was significantly greater in patients with a single nodule(vs patients with multi-nodules, P = 0.04). Two patients experienced major complications, including acute pulmonary edema(resolved with intervention) and intestinal perforation(led to death). The 1- and 2-year overall survival rates were 82% and 71%, respectively. Sex, tumor size, initial response, and recurrence status influenced survival, but did not reach the threshold of statistical significance. Child-Pugh class and the model for end-stage liver disease score were identified as predictors of survival by simple Cox regression, but only Child-Pugh class showed a statistically significant association to survival in multiple Cox regression analysis(HR = 15; 95%CI: 3-76 mo; P = 0.001). The 1-and 2-year cumulative disease-free survival rates were 65% and 36%, respectively. CONCLUSION: RFA is an effective therapy for local tumor control of early HCC, and patients with preserved liver function are the best candidates.     

Restriction of cell lysis by homologous complement: II. Protection of erythrocytes against lysis by newly activated complement

Our previous work revealed that homologous complement (C) was ineffective in lysing antibody-sensitized erythrocytes (EA) even at high concentrations. It was also shown that activation of complement on homologous EA resulted in the binding of C9 and the formation of EA bearing complement proteins C1 through C9 (EAC1-9), yet few hemolytic sites were formed. Instead, as shown here, the formation of homologous EAC1-9 caused the cells to become resistant to lysis even by heterologous complement during a second incubation. In contrast, when homologous EAC1-8 were produced by incubating EA with C9-depleted serum, such intermediates were not protected against lysis by heterologous complement during a second incubation. Furthermore, homologous C9 on EAC1-9 was able to reduce the hemolytic efficiency of heterologous complement without blocking C activation and the formation of new C5b-9 complexes. Protection was not modified when homologous EAC1-9 were produced in one step, by incubation of EA with serum, or sequentially by adding C9 to EAC1-8. The minimum number of 9-sites required to confer a protective effect on EAC1-9 was less than 200 per cell. Thus, in addition to its known effect in heterologous cell killing, homologous C9 is capable of protecting homologous cells against inadvertent complement lysis.     

Monoclonal antibodies against the 70-kilodalton iron-regulated protein of Neisseria meningitidis are bactericidal and strain specific.

When grown under iron limitation, Neisseria meningitidis expresses a number of outer membrane proteins (OMPs), one of which is a 70-kilodalton (kDa) major OMP. After immunization of mice with outer membrane preparations of iron-depleted cells of strain H44/76 (B:15:P1.7,16), hybridoma cell lines producing monoclonal antibodies against the 70-kDa OMP were obtained. Some of these monoclonal antibodies demonstrated strong bactericidal activity against the homologous strain H44/76 in the presence of human complement, suggesting potential application of the 70-kDa OMP as a vaccine component. However, none of the 10 selected monoclonal antibodies was able to recognize the corresponding protein from five heterologous strains of various serosubtyping characteristics. A polyclonal anti-70-kDa OMP serum also did not react with the other strains. This result shows that immunodominant surface-exposed epitopes of the meningococcal 70-kDa iron-limitation-inducible OMP are strain specific.     

The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial

BACKGROUND: Ankle sprains are the most common injuries in a variety of sports. HYPOTHESIS: A proprioceptive balance board program is effective for prevention of ankle sprains in volleyball players. STUDY DESIGN: Prospective controlled study. METHODS: There were 116 male and female volleyball teams followed prospectively during the 2001-2002 season. Teams were randomized by 4 geographical regions to an intervention group (66 teams, 641 players) and control group (50 teams, 486 players). Intervention teams followed a prescribed balance board training program; control teams followed their normal training routine. The coaches recorded exposure on a weekly basis for each player. Injuries were registered by the players within 1 week after onset. RESULTS: Significantly fewer ankle sprains in the intervention group were found compared to the control group (risk difference = 0.4/1000 playing hours; 95% confidence interval, 0.1-0.7). A significant reduction in ankle sprain risk was found only for players with a history of ankle sprains. The incidence of overuse knee injuries for players with history of knee injury was increased in the intervention group. History of knee injury may be a contraindication for proprioceptive balance board training. CONCLUSIONS: Use of proprioceptive balance board program is effective for prevention of ankle sprain recurrences.     

Strategies for the prevention of volleyball related injuries

Although the overall injury rate in volleyball and beach volleyball is relatively low compared with other team sports, injuries do occur in a discipline specific pattern. Epidemiological research has revealed that volleyball athletes are, in general, at greatest risk of acute ankle injuries and overuse conditions of the knee and shoulder. This structured review discusses both the known and suspected risk factors and potential strategies for preventing the most common volleyball related injuries: ankle sprains, patellar tendinopathy, and shoulder overuse.     

Trial of dextromethorphan/quinidine to treat levodopa‐induced dyskinesia in Parkinson's disease

Background : Nondopaminergic pathways represent potential targets to treat levodopa‐induced dyskinesia in Parkinson's disease (PD). This pilot‐study (NCT01767129) examined the safety/efficacy of the sigma‐1 receptor‐agonist and glutamatergic/monoaminergic modulator, dextromethorphan plus quinidine (to inhibit rapid dextromethorphan metabolism), for treating levodopa‐induced dyskinesia. Methods : PD patients were randomized to dextromethorphan/quinidine (45 mg/10 mg twice daily)/placebo in two 2‐week double‐blind, crossover treatment periods, with intervening 2‐week washout. After 14 days, a 2‐hour intravenous levodopa‐infusion was administered. Patient examinations were videotaped before infusion (“off” state) and every 30 minutes during and afterwards until patients returned to “off.” The primary endpoint was dyskinesia‐severity during infusion measured by Unified Dyskinesia Rating Scale part 3 area‐under‐curve scores (blinded expert rated). Additional endpoints included other dyskinesia/motor assessments, global measures of clinical‐change, and adverse‐events. Results : A total of 13 patients were randomized and completed the study (efficacy‐evaluable population). Dyskinesia‐severity was nonsignificantly lower with dextromethorphan/quinidine than placebo during infusion (area‐under‐curve 966.5 vs 1048.8; P = .191 [efficacy‐evaluable patients]), and significantly lower in a post‐hoc sensitivity analysis of the per‐protocol‐population (efficacy‐evaluable patients with ≥ 80% study‐drug‐compliance, n = 12) when measured from infusion start to 4‐hours post–infusion completion (area‐under‐curve 1585.0 vs 1911.3; P = .024). Mean peak dyskinesia decreased significantly from infusion‐start to return to “off” (13.3 vs 14.9; P = .018 [efficacy‐evaluable patients]). A total of 9 patients rated dyskinesia “much/very much improved” on dextromethorphan/quinidine versus 1‐patient on placebo. Dextromethorphan/quinidine did not worsen PD‐motor scores, was generally well tolerated, and was associated with more frequent adverse events. Conclusion : This study provides preliminary evidence of clinical benefit with dextromethorphan/quinidine for treating levodopa‐induced dyskinesia in PD. Larger studies with a longer treatment duration need to corroborate these early findings. © 2017 International Parkinson and Movement Disorder Society