Knee Injury Rates Research Articles

Fatigue-related changes in stance leg mechanics during sidestep cutting maneuvers

Background The increased number of women participating in sports has been paralleled by a greater knee injury rate in women compared to men. Among these injuries, those occurring to the anterior cruciate ligament are commonly observed during sidestep cutting maneuvers. In addition, general fatigue appears to correlate with injuries to the passive structures during a game. The purpose of the study was to examine the fatigue-related changes in lower limb mechanics during a cutting maneuver in female athletes. Methods Twelve college female soccer players were recruited. Sidestep cutting maneuvers were performed prior to, and after a fatiguing exercise (60-min shuttle run). Fatigue state was evaluated by calculating power output from countermovement jumps performed before and after the shuttle run. Three-dimensional stance leg hip, knee and ankle kinematics and kinetics during the cutting task were calculated and reported as initial ground contact angle, ranges of motion and peak moments of the stance phase. Cutting maneuver stance leg mechanics were analyzed through repeated measures two-way ANOVAs ( P < 0.05). Findings Jumping power output decrements suggested fatigue was induced. Sagittal and frontal planes kinematics and kinetics of the cutting task did not change after fatigue. In the transverse plane, the hip, knee and ankle joints were more externally rotated at touchdown, and during stance the knee underwent greater internal rotation. Interpretation Increased knee internal rotation has potentially important implication for increased injury risk when combined with unexpected perturbation faced in a game. Also, the fact that the sub-maximal level of fatigue did not lead to greater dynamic changes suggests a possible threshold of fatigue before function is dramatically affected.

Epidemiology of Knee Injuries among Boys and Girls in US High School Athletics

Background The knee joint is the second most commonly injured body site and the leading cause of high school sports-related surgeries. Knee injuries are among the most economically costly sports injuries and may require subsequent surgery or extensive and expensive rehabilitation. Purpose To report the incidence, risk, and severity of high school knee injuries across sports, genders, and type of exposure. Study Design Descriptive epidemiology study. Methods During the 2005–2006 and 2006–2007 school years, 100 US high schools were randomly selected for a nationally representative sample. Certified athletic trainers tracked injuries using an online injury surveillance system, High School RIO™, in 9 high school sports. Results There were 1383 knee injuries reported during 3 551 131 athlete exposures for a rate of 3.89 knee injuries per 10 000 athlete exposures. Although boys had a higher overall rate of knee injury (rate ratio, 1.38; confidence interval, 1.22–1.55), girls were twice as likely to sustain knee injuries requiring surgery (major knee injuries) than were boys (injury proportion ratio, 1.98; confidence interval, 1.45–2.70) and twice as likely to incur noncontact major knee injuries (injury proportion ratio, 1.98; confidence interval, 1.23–3.19) as were boys. Although illegal play was identified as a contributing factor in only 5.7% of all knee injuries, 20% of knee injuries resulting from illegal play required surgery. Conclusion Knee injury rates and patterns varied by sport, gender, and type of exposure. Identified gender differences included differences in injury rates, injury severity, and basic injury mechanism. Further surveillance is crucial for the development of targeted, evidence-based injury prevention strategies to reduce the morbidity and economic impact of knee surgeries.

The quadriceps angle and the incidence of knee injury in Indian long-distance runners

Objective. To investigate the incidence of knee injuries in runners and to determine the proportion of injuries involving abnormal quadriceps (Q)-angles. Design. One hundred male Indian runners between the ages of 25 and 65 years from 5 athletic clubs in Durban volunteered to participate in the study. The Q-angle was measured using a goniometer. Other relevant information was obtained using a validated questionnaire. The data were analysed by comparing measured Q-angles with ‘normal' values of Q-angles obtained from the literature. A paired t-test at a probability of 0.05 was used. Setting. Data were collected at club meetings. Main outcome measure. The primary outcome of the study was to determine the proportion of runners with abnormal Q-angles. Thereafter the rate of knee injuries in runners with abnormal Q-angles was determined. Results. Data from 88 runners were usable. Fifty-one per cent of the runners sustained knee injuries. Fifty-eight per cent of the sample had abnormal Q-angles. Sixty-seven per cent of the runners with abnormal Q-angles sustained knee injuries. Conclusion. More runners with abnormal Q-angles sustained knee injuries. There is a need to determine reference values for Q-angles for the South African population, the proportion of the population that present with abnormal Q-angles, and the reasons for this. South African Journal of Sports Medicine Vol. 19 (1) 2007: pp. 9-11

Biomechanical outcomes of a knee neuromuscular exercise programme among adolescent basketball players: A pilot study

Objective The objective was to test if a neuromuscular exercise programme would improve jump-shot landing technique of male adolescent basketball players. Design A non-equivalent pre-test–post-test control group experimental design was used. Setting Intervention (a 6-week neuromuscular exercise programme) took place at club practise venues and motion analysis at a biomechanics laboratory. Participants Five case and five matched control subjects participated. Main outcome measures Six high-speed (120 Hz), Oxford Metrics Vicon 370 cameras (Oxford Metrics, Oxford, UK) and a strain gauge AMTI force plate (AMTI Inc., Newton, MA, USA) synchronised were used to analyse three-dimensional (3-D) knee kinetics and kinematics of a jump-shot landing. Vertical ground reaction force, knee joint angles and negative work were calculated. Results Repeated ANOVA tests were used to compare the peak vertical ground reaction force, knee flexion, and total negative work prior to and following the exercise intervention. There was an overall significant difference for time of testing (pre-and-post intervention) and group allocation (case or control) for peak ground reaction force, knee flexion and negative working when landing from a jump-shot. Conclusion The improvements noted in the performance of case subjects suggest that neuromuscular exercises could aid in the reduction of injury rate or severity of knee injuries sustained during game play.

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...

Structured Exercises to Prevent Lower Limb Injuries in Young Handball Players

To investigate the effect of a structured warm-up program in reducing the occurrence of knee and ankle injuries in teenage handball players. Block randomized controlled trial with a sample size designed to achieve 90% power with [alpha] = 5% to detect a relative risk (RR) reduction of 50%. Clubs within the randomization blocks were matched by region, playing level, and number and sex of players. Norwegian Handball Federation clubs in the 16-year and 17-year divisions during the 2002 to 2003 season. Clubs in the division were invited to participate in the study before the season (n = 123 clubs recruited; 85% of the 145 invited clubs). After 3 clubs were excluded or dropped out, 1837 eligible players (uninjured at baseline) aged 15 to 17 years (86% young women) were included in the analysis. Coaches of the intervention group clubs (958 players) were instructed in exercises to improve awareness and control of knees and ankles during standing, running, cutting, jumping, and landing. The program comprised exercises with the ball, including the use of the wobble board and balance mat, for warm-up, technique, balance, and strength. Players were to spend 4 to 5 minutes on each group of exercises for a total of 15 to 20 minutes at the first 15 training sessions and thereafter once per week. Coaches recorded attendance and details of the sessions on standard forms. Coaches of the control group clubs (879 players) were asked to continue with their usual training methods and to record types and volume of exercises used. The primary outcome measure was an acute injury to the knee or ankle during a match or training session that required the player to have medical attention or miss part of the next session. Secondary outcomes were any injury to the lower limbs, injuries overall, and injuries to the upper limb. Injuries were recorded by physiotherapists blinded to group assignment who were in contact with the coaches at least every month. The physiotherapists interviewed injured players in person or by telephone as soon as possible (range, 1 day to 4 months). During the season 262 players (14%) were injured at least once (241 acute and 57 overuse injuries). In intention-to-treat analysis, the intervention group had lower risks than the control group of acute knee or ankle injuries (RR, 0.53; 95% CI, 0.35-0.81), lower limb injuries (RR, 0.51; CI, 0.36-0.73), any injury (RR, 0.49; CI, 0.36-0.68), and upper limb injuries (RR, 0.37; CI, 0.20-0.69). Rate ratios for moderate and major injuries (absence from play for 8 to > or =21 days) were lower for the intervention group for all injuries (P < 0.001) and for acute knee or ankle injuries (P < or = 0.03). Fewer players in the intervention group had > or =2 injuries. Risk of injury did not differ for young men and women. Crossovers to the other intervention occurred in 13% of the intervention clubs (noncompliance with the training program) and 22% of the control clubs (use of similar preventive exercises to the intervention group). The rate of acute knee and ankle injuries and all injuries to young handball players was reduced by half by a structured program designed to improve knee and ankle control during play.

Anterior Cruciate Ligament Tear Prevention in the Female Athlete

Anterior Cruciate Ligament Tear Prevention in the Female Athlete

Use of Discretionary Protective Equipment and Rate of Lower Extremity Injury in High School Athletes

Use of protective equipment is an important sports injury prevention strategy, yet use of protective equipment by high school athletes has seldom been studied. The authors analyzed data from a 3-year (1996-1999), stratified, two-stage cluster sample of athletes from 12 organized sports in 100 North Carolina high schools (n = 19,728 athlete-seasons). Information on each athlete's use of protective equipment and prior injury was collected during the preseason. Prospective information on injuries and weekly participation in games and practices was collected during the playing season. Use of lower extremity discretionary protective equipment tended to decrease the overall rate of lower extremity injury (rate ratio (RR) = 0.91, 95% confidence interval (CI): 0.72, 1.15). However, this slight protective effect was entirely due to kneepad use (for knee injury, RR = 0.44, 95% CI: 0.27, 0.74). Knee brace use and ankle brace use were associated with increased rates of knee injury (RR = 1.61, 95% CI: 1.08, 2.41) and ankle injury (RR = 1.74, 95% CI: 1.11, 2.72), respectively. This could be due to slippage of the brace during use, increased fatigue due to the energy cost of wearing a brace, or bias in the study. Further investigation into the effects of brace use is warranted.

Sports-Related Knee Injuries in Female Athletes

Knee injuries occur commonly in sports, limiting field and practice time and performance level. Although injury etiology relates primarily to sports specific activity, female athletes are at higher risk of knee injury than their male counterparts in jumping and cutting sports. Particular pain syndromes such as anterior knee pain and injuries such as noncontact anterior cruciate ligament (ACL) injuries occur at a higher rate in female than male athletes at a similar level of competition. Anterior cruciate ligament injuries can be season or career ending, at times requiring costly surgery and rehabilitation. Beyond real-time pain and functional limitations, previous injury is implicated in knee osteoarthritis occurring later in life. Although anatomical parameters differ between and within the sexes, it is not likely this is the single reason for knee injury rate disparities. Clinicians and researchers have also studied the role of sex hormones and dynamic neuromuscular imbalances in female compared with male athletes in hopes of finding the causes for the increased rate of ACL injury. Understanding gender differences in knee injuries will lead to more effective prevention strategies for women athletes who currently suffer thousands of ACL tears annually. To meet the goal in sports medicine of safely returning an athlete to her sport, our evaluation, assessment, treatments and prevention strategies must reflect not only our knowledge of the structure and innervations of the knee but neuromuscular control in multiple planes and with multiple forces while at play.

Delayed Anterior Cruciate Ligament Reconstruction in Adolescents with Open Physes

Background Treatment of anterior cruciate ligament rupture in adolescents with open physes is controversial. Hypothesis Delaying reconstruction until the physes bridge will affect the rate of additional knee injuries. Study Design Case control. Methods The physes group was 13 adolescents with open physes whose anterior cruciate ligament reconstructions were delayed until their physes bridged. Specific types of activity were absolutely restricted during the delay. The physes groups’ rates of additional injuries, identified arthroscopically at reconstruction, were compared to rates among 116 skeletally mature adolescents. The comparison adolescents were stratified into four groups by interval from injury to reconstruction (< 1 week, 1 to 6 weeks, 6 to 26 weeks, >26 weeks). Results The additional injury rates in the physes and four comparison groups were 46%, 50%, 47%, 43%, and 69%, respectively. Severity of additional injury, mechanism of injury, and rate of additional surgical procedures were similar among the groups. Conclusions There was no evidence that intentionally delayed anterior cruciate ligament reconstruction increased the rate of additional knee injuries. Delayed reconstruction is a valid treatment option for adolescents with open physes at injury. Absolute activity restriction is key to decreasing the risk of additional knee injuries.

Valgus knee motion during landing in high school female and male basketball players.

The purpose of this study was to utilize three-dimensional kinematic (motion) analysis to determine whether gender differences existed in knee valgus kinematics in high school basketball athletes when performing a landing maneuver. The hypothesis of this study was that female athletes would demonstrate greater valgus knee motion (ligament dominance) and greater side-to-side (leg dominance) differences in valgus knee angle at landing. These differences in valgus knee motion may be indicative of decreased dynamic knee joint control in female athletes. Eighty-one high school basketball players, 47 female and 34 male, volunteered to participate in this study. Valgus knee motion and varus-valgus angles during a drop vertical jump (DVJ) were calculated for each subject. The DVJ maneuver consisted of dropping off of a box, landing and immediately performing a maximum vertical jump. The first landing phase was used for the analysis. Female athletes landed with greater total valgus knee motion and a greater maximum valgus knee angle than male athletes. Female athletes had significant differences between their dominant and nondominant side in maximum valgus knee angle. The absence of dynamic knee joint stability may be responsible for increased rates of knee injury in females but is not normally measured in athletes before participation. No method for accurate and practical screening and identification of athletes at increased risk of ACL injury is currently available to target those individuals that would benefit from neuromuscular training before sports participation. Prevention of female ACL injury from five times to equal the rate of males would allow tens of thousands of young females to avoid the potentially devastating effects of ACL injury on their athletic careers.

PROSPECTIVE ONE-YEAR FOLLOW-UP OF KNEE INJURIES IN LEISURE-TIME PHYSICAL ACTIVITIES

PURPOSE To compare the risks of knee injuries in various commuting and lifestyle activities as well as in recreational and competitive sports in 15-to74-year-old Finnish population. METHODS 3 657 subjects were randomly selected from the nationwide population register of Finland. The subjects recorded all their physical activities that lasted over 15 minutes and registered all injuries that were sustained in these activities. The subjects were interviewed three times by telephone during the follow-up year. The knee injury risk per 1000 exposure hours was calculated for each activity. The effect of age and sex on the injury risk was also evaluated. RESULTS Fifteen percent of all reported injuries in the cohort (n=321) affected the knee. The risk of knee injury per 1000 exposure hours was 0.44 (95% CI 0.39 to 0.50) in recreational and competitive sports, 0.06 (95% CI 0.04 to 0.09) in commuting activities, and 0.04 (95% CI 0.03 to 0.06) in lifestyle activities. The highest knee injury incidence rates were seen in squash (5.4), judo (2.2), rinkball (2.1), floorball (2.0), wrestling (1.8), volleyball (1.4), skating (1.1), soccer (1.1), ice hockey (1.1) and track and field sports (1.1). In commuting (p = 0.046) and lifestyle (p = 0.038) activities the risk of knee injuries significantly increased with age. In recreational and competitive sports, in turn, the knee injury incidence significantly decreased with age (p < 0.001). In commuting activities (Hazard Ratio, HR= 5.99), endurance sports (1.40), and power and contact sports (2.10) the risk of knee injury was higher in women than in men. CONCLUSION The risk of knee injury is almost ten times higher in recreational and competitive sports than in commuting or lifestyle activities. The knee injury rates are high especially in various team sports and ball games. Large absolute number of knee injuries occurs during low-to-moderate intensity activities indicating that preventive efforts are needed also among less-demanding activities.

Knee injuries in motor vehicle collisions: a study of the National Accident Sampling System database for the years 1979–1995

A detailed study of knee injuries recorded in the 1979–1995 National Accident Sampling System database maintained by the National Highway Traffic Safety Administration was conducted. Injuries to other body regions were also considered in order to illustrate the relative frequency of knee injuries. This study demonstrated that knee injuries constitute ≈10% of all injuries recorded every year. However, the majority of these injuries were of low severity (i.e. contusions, abrasions, lacerations) with an abbreviated injury score (AIS) of 1. Most knee injuries occurred following a frontal collision with no intrusion. The study also indicated most knee fractures occur in crashes where the vehicle velocity differences (Δ Vs) were less than 45 kmph, with some occurring at Δ Vs as low as 10 kmph. Serious non-fracture knee injuries (i.e. ligament tears) rated AIS 2 accounted for 20 out of every 1000 injuries and predominantly occurred at Δ Vs below 25 kmph. In this study it was noted that women were more likely to experience a knee contusion than men. This study further suggests that knee impact scenarios have remained relatively constant over the years as the knee injury rates showed little variation. The rate of lap and shoulder belt use was lower in occupants who experienced a knee injury vs. the rate in the overall database and airbags were present in only a small number of cases. As this study largely included only vehicles without airbags it provides a good baseline for analysis of the influence of the airbag on knee injury trends in the future.

Sex-related injury patterns among selected high school sports.

This cohort observational study was undertaken to test the hypothesis that the incidence of injuries for girls participating in high school sports is greater than that for boys. From 1995 through 1997, players were included in our study if they were listed on the school's varsity team roster for boys' or girls' basketball, boys' or girls' soccer, boys' baseball, or girls' softball. Injuries and opportunities for injury were recorded daily. Certified athletic trainers reported injury and exposure data. Based on 39,032 player-seasons and 8988 reported injuries, the injury rates per 100 players for softball (16.7) and for girls' soccer (26.7) were higher than for baseball (13.2) and boys' soccer (23.4). The knee injury rates per 100 players for girls' basketball (4.5) and girls' soccer (5.2) were higher than for their male counterparts. Major injuries occurred more often in girls' basketball (12.4%) and soccer (12.1%) than in boys' basketball (9.9%) and soccer (10.4%). Baseball players (12.5%) had more major injuries than softball players (7.8%). There was a higher number of surgeries, particularly knee and anterior cruciate ligament surgeries, for female basketball and soccer players than for boys or girls in other sports.

The incidence of injury in Texas high school basketball. A prospective study among male and female athletes.

Recent publications have reported differences in the incidence, rate, risk, and type of sports injury among men and women. We undertook a prospective study to determine the incidence of injury among high school basketball players and to examine the differences in injury type, incidence, rate, and risk between male and female athletes. During a single basketball season, an injury survey of girls' varsity teams at 100 class 4A and 5A high schools in Texas was conducted. These data were previously reported. We surveyed the same 100 high schools during a subsequent season to gather injury data from the boys' varsity teams. The athletic trainer collected data on each reportable injury and reported the data weekly to the University Interscholastic League. A reportable injury was defined as one that occurred during a practice or a game, resulted in missed practice or game time, required physician consultation, or involved the head or the face. The boys' and girls' data were compared and statistically analyzed. The rate of injury was 0.56 among the boys and 0.49 among the girls. The risk of injury per hour of exposure was not significantly different between the two groups. In both groups, the most common injuries were sprains, and the most commonly injured area was the ankle, followed by the knee. Female athletes had a significantly higher rate of knee injuries including a 3.79 times greater risk of anterior cruciate ligament injuries. For both sexes, the risk of injury during a game was significantly higher than during practice.

Association between the menstrual cycle and anterior cruciate ligament injuries in female athletes.

Anterior cruciate ligament injury rates are four to eight times higher in women than in men. Because of estrogen's direct effect on collagen metabolism and behavior and because neuromuscular performance varies during the menstrual cycle, it is logical to question the menstrual cycle's effect on knee injury rates. Of 40 consecutive female athletes with acute anterior cruciate ligament injuries (less than 3 months), 28 (average age, 23 +/- 11 years) met the study criteria of regular menstrual periods and noncontact injury. Details concerning mechanism of injury, menstrual cycle, contraceptive use, and previous injury history were collected. A chi-square test was used to compute observed and expected frequencies of anterior cruciate ligament injury based on three different phases of the menstrual cycle: follicular (days 1 to 9), ovulatory (days 10 to 14), and luteal (day 15 to end of cycle). A significant statistical association was found between the stage of the menstrual cycle and the likelihood for an anterior cruciate ligament injury (P = 0.03). In particular, there were more injuries than expected in the ovulatory phase of the cycle. In contrast, significantly fewer injuries occurred in the follicular phase. These hormones may be a factor in the knee ligament injury dilemma in women.

Knee injuries in women collegiate rugby players.

We evaluated the prevalence and patterns of knee injuries in 810 women collegiate rugby players. Injuries that resulted in players missing at least one game were recorded and a questionnaire was used to delineate players' rugby and knee injury history. There were 76 total knee injuries in 58,296 exposures. This resulted in a 1.3 knee injury rate per 1000 exposures. Twenty-one anterior cruciate ligament tears were reported for a 0.36 incidence per 1000 exposures. Other injuries included meniscal tears (25), medical collateral ligament sprains (23), patellar dislocations (5), and posterior cruciate ligament tears (2). Sixty-one percent of the medial collateral ligament sprains occurred in rugby forwards and 67% of anterior cruciate ligament tears occurred in rugby backs. All other injuries occurred with equal frequency in backs and forwards. This study demonstrates that knee injury rates in women's collegiate rugby are similar to those reported for other women's collegiate sports. The overall rate of anterior cruciate ligament injury in women's rugby, however, is slightly higher than that reported for women soccer and basketball players.

Evaluation of knee braces in Swedish ice hockey players.

In this retrospective investigation we have determined the rate and types of knee injuries among Swedish ice hockey players, and related these data to the use of knee braces. Thirty-seven of the originally selected 50 hockey teams (74%) of elite or first division calibre took part in the study, and 600 players answered a questionnaire. A total of 254 previous knee injuries sustained while playing hockey were reported by 243 players; tears of the medical collateral ligament (60%), meniscus (15%) or anterior cruciate ligament (12%) were the most commonly reported injuries. Prophylactic knee braces were worn by 138 (23%) of the players. Of these, 122 (88%) had earlier sustained a knee injury, and 16 had not. A total of 17 knee injuries had occurred while the players were wearing a brace. Six of these players had previously uninjured knees while 11 had repeat injury in a brace despite earlier successful rehabilitation or operation. The most common injury in braced knees was a tear of the medial collateral ligament. We conclude that the number of knee injuries is high among Swedish ice hockey players, and that the efficacy of functional knee braces to reduce knee injuries is questionable.

Clinical Significance and Evaluation of Prophylactic Knee Brace Studies in Football

A review of nine studies of prophylactic knee braces in American tackle football found some support for the use of double-hinge braces in high school but little support for their use at the collegiate level. Problems with bias and confounding make it necessary that caution be exercised in the interpretation of the results of these studies, however,. To which groups these results might apply must also be considered. The two studies that assigned braces randomly found lower injury rates among high school and high-school-sized players for knee injuries and knee ligament injuries. Conversely a large, multiteam collegiate study found a significantly higher rate of knee injuries among brace users, a difference that remained when controlled for position, skill, and previous injury.

A Review of the Use of Prophylactic Knee Braces in Football

A review of nine studies of prophylactic knee braces worn by players in American tackle football lends some support for the use of double-hinged braces at the high-school level. Evidence for their use at the college level seems less persuasive. Caution should be exercised in interpreting these studies owing to the probable presence of bias and confounding variables and to difficulty in generalizing results beyond the study populations. The two studies that assigned braces randomly found lower injury rates for knees and knee ligaments among high-school and high-school size players. Conversely, a large, multiteam collegiate study found a significantly higher rate of knee injuries among brace users, a difference that remained when controlled for position, skill, and previous injury.