Biomedical subjects

J Ekstrand

Publications and source records attributed to J Ekstrand.

At least 19 recordsLinked to original sources

PubMed2006

Risk of injury in elite football played on artificial turf versus natural grass: a prospective two-cohort study.

OBJECTIVE: To compare injury risk in elite football played on artificial turf compared with natural grass. DESIGN: Prospective two-cohort study. SETTING: Male European elite football leagues. PARTICIPANTS: 290 players from 10 elite European clubs that had installed third-generation artificial turf surfaces in 2003-4, and 202 players from the Swedish Premier League acting as a control group. MAIN OUTCOME MEASURE: Injury incidence. RESULTS: The incidence of injury during training and match play did not differ between surfaces for the teams in the artificial turf cohort: 2.42 v 2.94 injuries/1000 training hours and 19.60 v 21.48 injuries/1000 match hours for artificial turf and grass respectively. The risk of ankle sprain was increased in matches on artificial turf compared with grass (4.83 v 2.66 injuries/1000 match hours; rate ratio 1.81, 95% confidence interval 1.00 to 3.28). No difference in injury severity was seen between surfaces. Compared with the control cohort who played home games on natural grass, teams in the artificial turf cohort had a lower injury incidence during match play (15.26 v 23.08 injuries/1000 match hours; rate ratio 0.66, 95% confidence interval 0.48 to 0.91). CONCLUSIONS: No evidence of a greater risk of injury was found when football was played on artificial turf compared with natural grass. The higher incidence of ankle sprain on artificial turf warrants further attention, although this result should be interpreted with caution as the number of ankle sprains was low.

Adolescent↗

PubMed2006

Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons.

BACKGROUND: Previous injury is often proposed to be a risk factor for football injury, but most studies rely on players reporting their own medical history and are thus potentially subject to recall bias. Little is known about the natural variation in injury pattern between seasons. OBJECTIVES: To study whether prospectively recorded injuries during one season are associated with injuries sustained during the following season, and to compare injury risk and injury pattern between consecutive seasons. METHODS: The medical staffs of 12 elite Swedish male football teams prospectively recorded individual exposure and time loss injuries over two full consecutive seasons (2001 and 2002). A multivariate model was used to determine the relation between previous injury, anthropometric data, and the risk of injury. RESULTS: The training and match injury incidences were similar between seasons (5.1 v 5.3 injuries/1000 training hours and 25.9 v 22.7/1000 match hours), but analysis of injury severity and injury patterns showed variations between seasons. Players who were injured in the 2001 season were at greater risk of any injury in the following season compared with non-injured players (hazard ratio 2.7; 95% confidence interval 1.7 to 4.3, p<0.0001). Players with a previous hamstring injury, groin injury, and knee joint trauma were two to three times more likely to suffer an identical injury in the following season, whereas no such relation was found for ankle sprain. Age was not associated with an increased injury risk. CONCLUSIONS: This study confirmed previous results showing that previous injury is an important risk factor for football injury. Overall injury incidences were similar between consecutive seasons, indicating that an injury surveillance study covering one full season can provide a reasonable overview of the injury problem among elite football players in a specific environment. However, a prolonged study period is recommended for analyses of specific injury patterns.

Adolescent↗

PubMed2006

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries.

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football injuries; this has made inter-study comparisons difficult. An Injury Consensus Group was established under the auspices of FIFA Medical Assessment and Research Centre. Using a nominal group consensus model approach, a working document that identified the key issues related to definitions, methodology and implementation was discussed by members of the group during a 2-day meeting. Following this meeting, iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis and causation are proposed. Proforma for recording players' baseline information, injuries and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented. The definitions and methodology proposed in the consensus statement will ensure that consistent and comparable results will be obtained from studies of football injuries.

Athletic Injuries↗

PubMed2006

High risk of new knee injury in elite footballers with previous anterior cruciate ligament injury.

BACKGROUND: Anterior cruciate ligament (ACL) injury is a severe event for a footballer, but it is unclear if the knee injury rate is higher on returning to football after ACL injury. OBJECTIVE: To study the risk of knee injury in elite footballers with a history of ACL injury compared with those without. METHOD: The Swedish male professional league (310 players) was studied during 2001. Players with a history of ACL injury at the study start were identified. Exposure to football and all time loss injuries during the season were recorded prospectively. RESULTS: Twenty four players (8%) had a history of 28 ACL injuries in 27 knees (one rerupture). These players had a higher incidence of new knee injury of any type than the players without ACL injury (mean (SD) 4.2 (3.7) v 1.0 (0.7) injuries per 1000 hours, p = 0.02). The risk of suffering a knee overuse injury was significantly higher regardless of whether the player (relative risk 4.8, 95% confidence interval 2.0 to 11.2) or the knee (relative risk 7.9, 95% confidence interval 3.4 to 18.5) was used as the unit of analysis. No interactive effects of age or any other anthropometric data were seen. CONCLUSION: The risk of new knee injury, especially overuse injury, was significantly increased on return to elite football after ACL injury regardless of whether the player or the knee was used as the unit of analysis.

Adult↗

PubMed2006

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries.

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football (soccer) injuries, making interstudy comparisons difficult. Therefore an Injury Consensus Group was established under the auspices of Fédération Internationale de Football Association Medical Assessment and Research Centre. A nominal group consensus model approach was used. A working document on definitions, methodology, and implementation was discussed by the group. Iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity, and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis, and causation are proposed. Proforma for recording players' baseline information, injuries, and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented.

Athletic Injuries↗

PubMed2005

Impact of social standing on sports injury prevention in a WHO safe community: intervention outcome by household employment contract and type of sport.

OBJECTIVES: As physical activity is promoted as part of a healthy lifestyle, sports injuries are becoming an important public health concern in many countries. The objective of this study is to investigate rates of sports injuries before and after implementation of a WHO Safe Community program. METHODS: Sports injury data were collected pre- and post-implementation from all individuals below 65 years of age during 1 year in the targeted municipality (population 41,000) and in a control municipality (population 26,000). A quasi-experimental design was used and individuals were divided into three categories based on household relationship to the labour market. RESULTS: There were no differences between socio-economic categories regarding pre-intervention injury rates. No statistically significant post-intervention changes in injury rate were observed in the control area or among any females in either area. In the intervention area, a statistically significant (p = 0.011) decrease in injury rate was observed among male members of households in which the vocationally important member was employed. A statistically significant decrease was observed in injuries sustained in team sports among male members of households in which the vocationally important member was employed (p = 0.001) and among members of households in which the vocationally important member was self employed (p<0.05). CONCLUSIONS: The study indicates areas for improvement in the civic network based WHO Safe Community model. The results show that females, participants in individual sports, and members of non-vocationally active households were less affected by the interventions. These facts have to be addressed in planning future community based sports injury prevention programmes and their evaluations.

Adolescent↗

PubMed2005

UEFA Champions League study: a prospective study of injuries in professional football during the 2001-2002 season.

BACKGROUND: No previous study on adult football involving several different countries has investigated the incidence and pattern of injuries at the highest club competitive level. OBJECTIVE: To investigate the risk exposure, risk of injury, and injury pattern of footballers involved in UEFA Champions League and international matches during a full football season. METHOD: Eleven top clubs (266 players) in five European countries were followed prospectively throughout the season of 2001-2002. Time-lost injuries and individual exposure times were recorded during all club and national team training sessions and matches. RESULTS: A total of 658 injuries were recorded. The mean (SD) injury incidence was 9.4 (3.2) injuries per 1000 hours (30.5 (11.0) injuries per 1000 match hours and 5.8 (2.1) injuries per 1000 training hours). The risk of match injury was significantly higher in the English and Dutch teams than in the teams from France, Italy, and Spain (41.8 (3.3) v 24.0 (7.9) injuries per 1000 hours; p = 0.008). Major injuries (absence > 4 weeks) constituted 15% of all injuries, and the risk of major injury was also significantly higher among the English and Dutch teams (p = 0.04). National team players had a higher match exposure, with a tendency towards a lower training injury incidence than the rest of the players (p = 0.051). Thigh strain was the most common injury (16%), with posterior strains being significantly more common than anterior ones (67 v 36; p < 0.0001). CONCLUSIONS: The risk of injury in European professional football is high. The most common injury is the thigh strain typically involving the hamstrings. The results suggest that regional differences may influence injury epidemiology and traumatology, but the factors involved are unclear. National team players have a higher match exposure, but no higher risk of injury than other top level players.

Adult↗

PubMed2005

Methods for epidemiological study of injuries to professional football players: developing the UEFA model.

A problem with epidemiological studies of football injuries is the inconsistent manner in which injury is defined and data are collected. Projects have been initiated to study the incidence and causes of injury in football, but there is no uniformly accepted reporting system. In this report, some common pitfalls encountered in the recording of injury are addressed, and practical guidelines for epidemiological studies are provided. An injury reporting system developed for the UEFA Football Safety Project for studies on professional footballers is used as a starting point for a general discussion on injury registration and compared with other existing reporting systems. The recording definition of injury may vary between studies depending on its purpose. A time loss injury definition is practical for all playing levels, and, as a minimum, results on time loss injuries should therefore always be reported separately to allow direct comparisons between studies. There is a need to agree on a uniform sports injury classification system with corresponding diagnostic criteria, as well as standardised return to play criteria after injury.

Athletic Injuries↗

PubMed2004

A congested football calendar and the wellbeing of players: correlation between match exposure of European footballers before the World Cup 2002 and their injuries and performances during that World Cup.

OBJECTIVES: To investigate the correlation between exposure of footballers in European clubs to match play in the months before the World Cup 2002 and their injuries and performances during that World Cup. METHODS: The team doctors at 11 of the best football clubs in Europe prospectively recorded players' exposure and injuries during the 2001-2002 season (July 2001-May 2002). Sixty five players participated in the World Cup in Korea/Japan (June 2002). During the World Cup, the clubs reported injuries sustained by these players, and their performance was evaluated by three international experts. RESULTS: The number of team matches during the season varied between 40 and 76 for the different countries involved. The individual player had a mean of 36 matches during the season. Top players played more matches, especially during the final period of the season. Players who participated in the World Cup played more matches during the season than those who did not (46 v 33 matches). World Cup players did not show any increased risk of injury during the season. About 29% incurred injuries during the World Cup, and 32% performed below their normal standard. The players who underperformed had played more matches during the 10 weeks before the World Cup than those who performed better than expected (12.5 v 9, p<0.05). Twenty three (60%) of the 38 players who had played more than one match a week before the World Cup incurred injuries or underperformed during the World Cup. CONCLUSIONS: There is considerable variation in the number of matches played per season in European professional football leagues. Top level players are obliged to play many matches especially during the final period of the season.

Adult↗

PubMed2001

Mercury exposure in utero and during infancy.

Mercury in blood samples was speicated from mothers and their infants up to 2 mo after delivery. There were significant correlations between umbilical cord blood and maternal blood for methylmercury (MeHg) and inorganic mercury (I-Hg) levels. The MeHg levels in cord blood were significantly higher than in maternal blood, while I-Hg levels were significantly higher than in maternal blood, while I-Hg levels were about the same. The maternal MeHg and I-Hg levels remained stable during the sampling period, whereas the MeHg concentration in infant blood decreased more than 45% between the 72-h and 2 mo sampling times. The I-Hg levels in infant blood were low at birth, and remained low during the sampling period. The results of the present study do not support I-Hg absorption through milk as a significant source of exposure. However, the number of observations is small, and a larger study is warranted in order to verify the data.

Adult↗

PubMed2001

Reconstruction of the anterior cruciate ligament with the iliotibial band autograft in patients with chronic knee instability.

We performed combined internal and external anterior cruciate ligament (ACL) reconstruction with the iliotibial band autograft in 169 consecutive patients with chronic ACL insufficiency who were followed up for 24-61 months. Of these, 155 (91%) agreed to an additional independent observer follow-up after 24-92 months. Eight patients (5%) had sustained a rerupture/elongation of the graft and were operated on again; nine (6%) had sustained a tear of the contralateral ACL. Knee function and activity increased after the reconstruction. Lysholm scores improved from median 81 preoperatively to 99 at follow-up and Tegner scores from median 4 to 7. At follow-up 97 (71%) were active at the same level as prior to injury. In 17 of the 40 patients (12%) dropping to a lower activity level this was due to knee problems. The side-to-side difference in anterior-posterior knee laxity was more than 3 mm in 18 knees (13%) and more than 5 mm in 3 knees (2%). Including eight reruptures, this results in a "stability" failure rate of 8.8%. The overall IKCD rating showed normal knee function in 88 (73%) and nearly normal knee function in 30 (25%). Anterior knee pain was present in 14 (10%) of the patients at follow-up. Patients with isolated ACL injury had higher Lysholm scores and Tegner scores than patients with associated injuries. No clinical signs of varus knee development were seen. Of the 155 patients 94% would have the procedure repeated if necessary with the knowledge that they have today. The combined internal and external iliotibial band procedure can restore knee stability and function in the majority of chronic ACL-insufficient knees.

Activities of Daily Living↗

PubMed2001

Expression of keratins in normal, immortalized and malignant oral epithelia in organotypic culture.

Keratins have been extensively studied in tissues and cultured keratinocytes but limited information is available on epithelia reconstructed in vitro. The aim of this study was to examine keratin expression in organotypic epithelia with normal (NOK), immortalized (SVpgC2a) and malignant (SqCC/Y1) human buccal cells. Organotypic epithelia were derived from 10 days of culture at the air-liquid interface of collagen gels containing human oral fibroblasts using a standardized serum-free medium. Sections were stained immunohistochemically with selected mono-specific antibodies to a range of keratins. Organotypic epithelia showed sharp differences in keratin expression and distribution. K4/K13, K1/K10, K6/K16 were variably expressed in NOK and SqCC/Y1 but were not detected in SVpgC2a. K5 was expressed in all organotypic epithelia but K14 was absent in SVpgC2a. K7 and K8 showed variable expression while K18 was expressed uniformly in all epithelia. K19 was expressed consistently in NOK and K20 was distributed heterogeneously in SVpgC2a. Overall, organotypic cultures of normal keratinocytes express many of the same keratins as buccal mucosa. Further, the loss of keratins in SVpgC2a and their retention in SqCC/Y1 have several features in common with the respective keratin profile of oral epithelial dysplasia and well-differentiated oral squamous cell carcinoma. Although qualitative and quantitative differences exist compared to keratin expression in vivo, these cell lines in organotypic culture may serve in studies of the multi-step progression of oral cancer.

Carcinoma, Squamous Cell↗

PubMed2001

Reconstruction of anterior cruciate ligament deficient knees in soccer players with an iliotibial band autograft. A prospective study of 132 reconstructed knees followed for 4 (2-7) years.

One hundred and thirty-two consecutive soccer players (117 males and 15 females, median age 23, range 16-39 years) underwent primary reconstruction of the anterior cruciate ligament (ACL) with an iliotibial band (ITB) autograft. All patients were followed prospectively for a minimum of 2 years. One hundred and eighteen patients (89%) attended an independent observer follow-up after a median of 47 (24-92) months. The time before participating in soccer was a median of 7 (5-24) months. At a median of 4 years, 80 (68%) were still active soccer players, while 38 had changed activity to a lower level. Twenty-five gave up soccer playing for reasons unrelated to the knee, and 13 (11%) gave up due to problems from the reconstructed knee. The Lysholm score improved from a median of 82 (range 42-99, mean [SD] 80.5 [+/-11.9]) points prior to the operation to a median of 99 (range 57-100, mean [SD] 94.6 [+/-8.5]) at follow-up. The Tegner score improved from a median of 3.5 (0-7) preoperatively to 9 (1-10). Four patients (3%) sustained a rupture of the graft: three ruptures occurred among the 15 females (20%), and one was seen among the 117 males (0.8%) (P=0.01). Eight per cent had predominantly minor cosmetic complaints from the donor-site hernia, while 51% had temporary discomfort from the staples used for graft fixation. Using the ITB autograft for ACL reconstruction, we found excellent and good results in soccer players with ACL deficiency and high demands for optimal knee function. The failure rate in general was comparable with other methods, and the majority was still active in soccer sports at a median of 4 years after surgery. An unacceptably high rerupture rate was registered in female players.

Adolescent↗

PubMed2001

Site of action of GABA(B) receptor for vagal motor control of the lower esophageal sphincter in ferrets and rats.

BACKGROUND & AIMS: Stimulation of gamma-aminobutyric acid B metabotropic receptors (GBRs) by baclofen reduces the incidence of transient lower esophageal sphincter (LES) relaxations. The GBR effect may be a result of a central site of action in the dorsal vagal complex, where upper gastrointestinal vagal reflexes are integrated. Therefore, we first localized GBR immunostaining in the dorsal vagal complex. Next, we tested the hypothesis that baclofen modulates LES motor tone via GBR expressed by vagal efferent neurons. METHODS: An antibody against the human GBR1b isoform was characterized and used for immunocytochemistry in rats and ferrets. Functional studies involved microinjection of L-glutamate into the caudal dorsal motor nucleus of the vagus to evoke an LES relaxation in decerebrate unanesthetized ferrets. RESULTS: In both species, GBR1b was expressed in preganglionic motor neurons and, in ferrets, the receptor was highly expressed in identified LES-projecting preganglionic neurons. GBR1b immunostaining was also pronounced in the subnucleus centralis of the nucleus tractus solitarius. This distribution implicates GBR in control of the esophageal phase of swallowing at the level of the central program generator. In functional studies, centrally evoked LES relaxation (-73% +/- 8% mm Hg) was significantly attenuated after 7 micromol/kg intravenous baclofen (-37% +/- 10%; N = 5). CONCLUSIONS: These data all suggest that GBR agonists inhibit LES relaxation via a site of action associated with vagal motor outflow to the LES.

Amino Acid Sequence↗

PubMed2001

Mercury uptake and kinetics after ingestion of dental amalgam.

The aim of the present study was to investigate the G-1 uptake of mercury (Hg) after intake of a single dose of amalgam-Hg, followed by pharmacokinetic analysis of the data. Eleven volunteers without amalgam fillings ingested 1.00 g amalgam powder. Hg in plasma vs. time was analyzed with a two-compartment model by means of mixed-effects modeling. A fraction of the absorption rate of Hg to the central compartment was inversely proportional to the plasma ferritin levels. The population mean half-life of the terminal phase of Hg in plasma was 37 days, with a considerable standard deviation in the population. The absorbed fraction of the administered dose was estimated to be about 0.04%. It is concluded that the G-1 uptake of Hg is of quantitative importance during dental treatment.

Administration, Oral↗

PubMed2000

Immunocytochemical distribution of the GABA(B) receptor splice variants GABA(B) R1a and R1b in the rat CNS and dorsal root ganglia.

The anatomical distribution of the GABA(B) receptor (GBR) splice variants GBR1a and 1b in the CNS has not previously been studied. In the present study, distribution of the splice variants was mapped using immunohistochemistry. Polyclonal antibodies against splice variant unique epitopes were raised in rabbits. Affinity purified antibodies were used according to routine immunohistochemical procedures in sections from the rat CNS or dorsal root ganglia (DRG). The staining intensity was high in the cerebral cortex but lower in basal ganglia and the hippocampus. In the cerebellum, there was a marked difference in the distribution of GBR1a- and 1b-like immunoreactivity (LI). GBR1a-LI was preferentially localised in the granule cell layer whilst GBR1b-LI was mostly found in Purkinje cells and in the molecular layer. Cell bodies of the deep cerebellar nuclei stained for the GBR1a antibody while terminals surrounding the cell bodies were strongly labelled with the GBR1b antibody. A similar pre- vs postsynaptic pattern was seen in several nuclei ventral or caudal to the cerebellum (e.g. the cochlear nucleus, the facial nucleus, the spinal cord) but not in regions rostral to the cerebellum. In the spinal cord, strong labelling for both antibodies was seen in the dorsal horn. The GBR1b but not the GBR1a antibody stained tanycytes in the epithelium of the 3rd ventricle and in the central canal at the brain stem level. DRG neurons were positive for both the GBR1a and 1b antibody, but the former stained the cells much more intensely. Satellite cells were labelled with the GBR1b antibody. The most important aspect of these findings is that in some nuclei, GBR1b may mediate inhibition of transmitter release while in the same regions, GBR1a may mediate postsynaptic inhibition. Further, the observations support previous findings that GBR1b is the predominant splice variant in Purkinje cells.

Animals↗

PubMed2000

Retrospective study of orthodontic bonding without liquid resin.

The aim of this study was to evaluate the retention of fixed orthodontic appliances bonded without liquid resin with the use of a retrospective study design. Patients from each of 2 consultant orthodontists in the same specialty clinic were chosen under strict selection criteria. In the test group (n = 37), composite material (Phase II) without liquid resin was used to bond full arch fixed appliances onto patients' upper teeth. Patients' appliances, which were bonded with Phase II composite and liquid resin, were used as the control group (n = 37). The duration of the appliance survival, from the date of appliance bonding to the date of first accidental bracket loss, was analyzed by Kaplan-Meier product limit method and log-rank test. Our data suggested that supragingival orthodontic metal brackets seemed to bond on healthy enamel surfaces and to work equally well either with or without the use of liquid resin. The total percentages of bond failure, roughly 6%, were similar in both test and control groups. Approximately 73% of all patients in the test group and 57% of the patients in the control group experienced no bond failure at all throughout the entire course of treatment.

Adolescent↗

PubMed2000

In vitro shear bond strength of orthodontic bondings without liquid resin.

This study aimed at evaluating the early shear bond strength of enamel-composite-bracket adhesion accomplished without the use of liquid resin. Orthodontic brackets were bonded to the buccal surfaces of healthy extracted premolars in the test group by Transbond XT (n = 8) and Phase II (n = 8) composites but not the enclosed liquid resins in these products. Brackets bonded with the same materials (n = 8 for each) along with their corresponding liquid resin served as controls. The specimens were tested for shear bond strength after 24-h storage in water at 37 degrees C. The fractured surfaces were graded with Adhesive Remnant Index (ARI) under a 2x-dissection microscope. Enamel of the randomly selected test and control specimens was dissolved by 20% formic acid. Afterwards, the enamel side of the bonding materials in both groups (n = 4) was examined under the scanning electron microscope. ANOVA was used for statistical analyses. Our laboratory data suggest that the enamel adhesion produced by these two commercial materials without the use of liquid resin does not differ significantly in their early in vitro shear bond strength.

Acrylic Resins↗