Effect of functional bracing on knee injury in skiers with anterior cruciate ligament reconstruction: a prospective cohort study

BACKGROUND: The role of knee bracing in anterior cruciate ligament reconstructions is controversial. HYPOTHESIS: Functional bracing will have an effect on subsequent knee injury in skiers with anterior cruciate ligament reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: From 1991 to 1997, 11606 skiers at a major destination ski resort underwent preseason knee screening. The anterior cruciate ligament-reconstructed group consisted of 820 skiers who had had an anterior cruciate ligament reconstruction 2 years or more earlier. Of these, 257 skiers selected the use of functional knee brace during skiing. The dependent variable was subsequent knee injury, identified via workers' compensation records. Covariates included age, gender, ski occupation, Lachman grade, pivot-shift grade, KT-1000 arthrometer manual maximum displacement, and use of a functional brace. Univariate and multivariate risk factors for subsequent knee injury were determined. RESULTS: In this study, 257 skier-employees with anterior cruciate ligament reconstruction wore braces and 563 skier-employees with anterior cruciate ligament reconstruction did not. Braced skiers had significantly higher preseason rates of grade II or higher Lachman and pivot-shift tests (braced, 29% and 22%, respectively; nonbraced, 11% and 10%, respectively; P < .05). Sixty-one subsequent knee injuries were identified, 51 (8.9 injuries/100 knees/ski season) in the nonbraced group and 10 (4.0 injuries/100 knees/ski season) in the braced group (P = .009). Nonbraced skiers were 2.74 times more likely to suffer subsequent injury than were braced skiers (odds ratio, 2.74 [confidence interval, 1.2-4.9]). Logistic regression modeling identified nonbracing as a significant independent multivariate risk factor for subsequent knee injury in the high-demand skiers with anterior cruciate ligament reconstruction. CONCLUSION: Because of the increased risk of subsequent knee injury in nonbraced skiers, the authors recommend functional bracing for skiers with anterior cruciate ligament reconstruction. Whether the protective effect of functional bracing can be extrapolated to other high-demand patients is yet to be determined.     

Injury risk factors among telemark skiers

We performed a population survey of telemark skiers over two ski seasons to determine specific risk factors for injury. The survey inquired about the skier's sex, experience, equipment used, injuries, and number of days skied in each season. The respondents completed the surveys whether or not they were injured while skiing. We received 677 responses from telemark skiing clubs, with 19,962 skier-days of data. The number of self-reported injuries was 178, for an overall self-reported injury rate of 8.9 per 1000 skier-days. Knee injuries (N = 48) were the most common injury (27%), followed by thumb (N = 32, 18%) and shoulder (N = 21, 12%) injuries. Specific risk factors for injury were identified with multivariate regression and survival analysis. The skill level of the skier had a significant injury-sparing effect, as did the use of plastic telemark boots. The protective effect of the plastic boots was likely due to the increased stability they provided compared with traditional leather boots. There were fewer knee injuries with the recently available releasable bindings for telemark skis. Sex and age had no significant impact on injury rates in this study population. As all reported deaths associated with telemark sking were due to environmental hazards, skiers must continue to pay close attention to these hazards in the backcountry.     

Registration of cruciate ligament injuries in Norwegian top level team handball. A prospective study covering two seasons

All cruciate ligament injuries in the three upper divisions for men and women (3392 players) in Norwegian team handball in the 1989-90 and 1990–91 seasons were registered. A questionnaire was mailed to all injured players. Ninety-three cruciate ligament injuries were registered; 87 in the anterior cruciate ligament (ACL), and six in the posterior cruciate ligament (PCL). Among women, 1.8% were injured compared with 1.0% of the men. In the first division, the risk of being injured was considerably higher: 4.5% of the players had a cruciate ligament injury. There were 0.97 cruciate ligament injuries per 1000 playing hours in the three divisions taken together. Seventy-five per cent of the injuries occurred during games. Ninety-five per cent involved no contact between players. Activities in which the friction between shoe and floor was significant caused 55% of the injuries. Injuries caused by running into another player contributed to only 5% of the injuries. No significant differences were observed in injury incidence during matches between different types of floors (parquet, Pulastic and other synthetic sufaces).     

Alpine ski injuries and their prevention

Alpine skiing is a popular sport with significant risk of injury. Since the 1970s, injury rates have dropped from approximately 5 to 8 per 1000 skier-days to about 2 to 3 per 1000 skier-days. The nature of the injuries has also been transformed over the same period. Lower leg injuries are becoming less common while the incidence of knee sprains and upper extremity injuries is becoming more common. Much of this change can be attributed to advancements in binding technology, which effectively reduces lower leg injury, but does not adequately address the issue of knee sprains. Along with design, binding adjustment and maintenance are important preventative factors. Poorly adjusted bindings have been correlated with increased injury rates. Upper extremity injuries constitute approximately one-third of skiing injuries, with ulnar collateral ligament sprains and shoulder injuries being the most common. Strategies to prevent these include proper poling technique and avoidance of non-detachable ski pole retention devices. Spinal injuries in skiers have been traditionally much less common than in snowboarders, but this disparity is likely to diminish with the recent trend of incorporating snowboarding moves into skiing. Strategies to help reduce these injuries include promoting the development of terrain parks and focussing on proper technique during such moves. Head injuries have been increasing in incidence over recent decades and account for more than half of skiing-related deaths. The issue of ski helmets remains controversial while evidence for their efficacy remains under debate. There is no evidence to demonstrate that traditional ski instruction reduces injury frequency. More specific programmes focussed on injury prevention techniques are effective. The question of pre-season conditioning to prevent injuries needs further research to demonstrate efficacy.     

Are oral contraceptive use and menstrual cycle phase related to anterior cruciate ligament injury risk in female recreational skiers?

Oral contraceptive use and menstrual cycle phase are suggested to influence the risk of anterior cruciate ligament (ACL) injuries in female athletes. However, only few data are available for recreational sports. Therefore, female recreational skiers with a non-contact ACL injury and age-matched controls completed a self-reported questionnaire relating to menstrual history, oral contraceptive use and previous knee injuries. Menstrual history data were used to group subjects into either preovulatory or postovulatory phases of menstrual cycle. Our findings suggest that oral contraceptive use did not show any protective effect against ACL injuries nor did self-reported previous knee injuries show any association with ACL injury rate in recreational alpine skiing. Analysis of menstrual history data revealed that recreational skiers in the preovulatory phase were significantly more likely to sustain an ACL injury than were skiers in the postovulatory phase.     

The relationship between menstrual cycle phase and anterior cruciate ligament injury: a case-control study of recreational alpine skiers

BACKGROUND: Female athletes suffer a greater incidence of anterior cruciate ligament tears compared with male athletes when participating in common sports; however, very little is known about the factors that explain this disparity. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Female recreational alpine skiers with an anterior cruciate ligament rupture and age-matched control skiers provided a serum sample and self-reported menstrual history data immediately after injury. Both serum concentrations of progesterone and menstrual history were then used to group subjects into either preovulatory or postovulatory phases of the menstrual cycle. RESULTS: Analysis of serum concentrations of progesterone revealed that alpine skiers in the preovulatory phase of the menstrual cycle were significantly more likely to tear their anterior cruciate ligaments than were skiers in the postovulatory phase (odds ratio, 3.22; 95% confidence interval, 1.09-9.52; P = .027). Analysis of menstrual history data found similar results, but the difference was not statistically significant (odds ratio, 2.38; 95% confidence interval, 0.86-6.54; P = .086). CONCLUSION: The likelihood of sustaining an anterior cruciate ligament injury does not remain constant during the menstrual cycle; instead, the risk of suffering an anterior cruciate ligament disruption is significantly greater during the preovulatory phase of the menstrual cycle compared with the postovulatory phase. CLINICAL RELEVANCE: Phase of menstrual cycle may be one of the risk factors that influence knee ligament injury among female alpine skiers. The findings from this study should be considered in subsequent studies designed to identify persons at risk for anterior cruciate ligament injury and to develop intervention strategies.     

Comparative injury rates of uninjured, anterior cruciate ligament-deficient, and reconstructed knees in a skiing population.

To evaluate the risks of skiing after anterior cruciate ligament injury with or without reconstruction, we performed a 3-year study of 5646 skiers employed by a large ski resort. All skiers underwent knee ligament examinations before entering the study. The participants were divided into three groups based on whether they had never had an anterior cruciate ligament injury (N = 4748), were unilaterally deficient of the ligament (N = 138), or had undergone a unilateral reconstruction of the ligament at least 1 year before (N = 274). The rates of knee injuries requiring evaluation by a physician or time off work were calculated. The results of the reconstructed knees were further evaluated to determine whether ligament repair with semitendinosus/gracilis or patellar tendon autograft had a higher injury rate. Compared with knees with intact anterior cruciate ligaments, ligament-deficient knees had a 6.2-times higher rate of injuries, and knees in which the ligament had been reconstructed had a 3.1-times higher rate. The differences between each of the three groups were significant. Injuries to ligament-intact knees were less severe, with 13% requiring surgery, while 39% of the injuries in the ligament-deficient and 41% of the injuries in the reconstructed-ligament knees required surgery. The rates of injury for the graft types were not significantly different, but skiers with a semitendinosus/gracilis tendon autograft were significantly more likely to rupture their graft than skiers with a patellar tendon autograft.     

Alpine ski bindings and injuries. Current findings.

In spite of the fact that the overall incidence of alpine ski injuries has decreased during the last 25 years, the incidence of serious knee sprains usually involving the anterior cruciate ligament (ACL) has risen dramatically since the late 1970s. This trend runs counter to a dramatic reduction in lower leg injuries that began in the early 1970s and to date has lowered the risk of injury below the knee by almost 90%. One of the primary design objectives of modern ski boots and bindings has been to protect the skier from tibia and ankle fractures. So, in that sense, they have done an excellent job. However, despite advances in equipment design, modern ski bindings have not protected the knee from serious ligament trauma. At the present time, we are unaware of any binding design, settings or function that can protect both the knee and lower extremities from serious ligament sprains. No innovative change in binding design appears to be on the horizon that has the potential to reduce the risk of these severe knee injuries. Indeed, only 1 study has demonstrated a means to help reduce this risk of serious knee sprains, and this study involved education of skiers, not ski equipment. Despite the inability of bindings to reduce the risk of severe knee injuries there can be no doubt that improvement in ski bindings has been the most important factor in the marked reduction in incidence of lower leg and ankle injuries during the last 25 years. The authors strongly endorse the application of present International Standards Organisation (ISO) and American Society for Testing and Materials (ASTM) standards concerning mounting, setting and maintaining modern 'state of the art' bindings.     

Reduction of injuries in downhill skiing by use of an instructional ski-video: a prospective randomised intervention study

Despite various attempts at prevention, injury in downhill skiing continues to be a worrisome recreational problem. The purpose of this study was to test the effect of an instructional ski video on the behaviour and injuries of 763 downhill skiers. They were enrolled in two study groups, based on whether or not an instructional video had been shown in their bus on the way to a skiing resort. The video focussed on information regarding how to get started in downhill skiing and injury prevention. The outcome parameters, behaviour (binding test and adjustment), injury risk, type and consequence, were registered on the return trip 8 days later by a questionnaire. In the intervention group all outcome parameters changed significantly. The binding test was performed by 86% in the intervention group and by only 59% in the control group (P < 0.05). Adjustment of the bindings was done by 22% in the intervention group vs 14% in the control group. Regarding injury risk, 205 injuries were seen in 158 persons (20.7%) which is 26 injured skiers per 1000 skier-days and 33.6 injuries per 1000 skier-days. In the intervention group 16% of all skiers were injured vs 23% in the control group, yielding a reduction in injury risk of 30% (P < 0.05). Injuries caused by falls were seen in 12.6% in the intervention group vs 16.2% in the control group (P < 0.05). Injuries caused by collision were seen in 6% of the intervention group vs 12% in the control group (P < 0.05). The overall mean injury risk was 16 injuries per 1000 falls. Knee injuries made up 32.6% of the total. For inexperienced skiers the knee injury risk was significantly lower if the bindings had been tested (P < 0.05). Therefore, an instructional ski video can change the behaviour of downhill skiers and reduce the injury risk and consequences significantly. Received: 26 March 1997 Accepted: 20 December 1997     

Injury profile of competitive alpine skiers: a five-year cohort study

Purpose

The aim of this study was to make a survey of injuries in young elite alpine skiers.

Methods

During 5 years, all students at the Swedish Ski High schools were prospectively followed regarding injuries, time of exposure, injury location, type of injury, injury severity and gender. Four hundred and thirty-one skiers, 215 males and 216 females completed the entire study.

Results

Of 431 skiers, 193 (91 males, 102 females) sustained 312 injuries during the 5-year study period. The injury incidence for males was 1.62 injuries/1,000 ski hours or 2.97 injuries/100 months at a Ski High school, and the corresponding values for females were 1.77 and 3.25, respectively. Forty-one percent of the injuries involved the knee, 69% were ligament injuries, and 49% were classified as severe injuries. Of 190 injured skiers, 120 injured their left leg (P = 0.0097). This was their first time injury. The risk of sustaining a re-injury or a new injury increased the sooner the first time injury occurred (P = 0.001).

Conclusion

There was a high risk for alpine ski students to sustain an injury during their education at the Swedish Ski High schools. Most injuries, especially ligament injuries, occurred in the knee joint in both males and females. Both genders were more likely to sustain injuries to the left than to the right leg. Nearly 50% of the injuries were classified as severe.

Level of evidence

II.     

Spinal injuries in skiers and snowboarders

Spinal injuries are among the most devastating injuries associated with recreational sports. Snowboarding spinal injury patterns have not been described. During two seasons (1994 to 1995 and 1995 to 1996), 34 skiers and 22 snowboarders suffered serious spinal injuries (fracture or neurologic deficit or both) at two ski areas in British Columbia, Canada. Ski patrol records, the Provincial Trauma Database, and hospital records were reviewed. Injury rates were based on computerized lift-ticket data and a population estimate of 15% snowboarders (ski patrol observation). The incidence of spinal injury among skiers was 0.01 per 1000 skier-days, and among snowboarders was 0.04 per 1000 snowboarder-days. Mean age was 34.5 years for skiers and 22.4 years for snowboarders. Seventy percent of the skiers were men, whereas all of the snowboarders were men. Jumping (intentional jump > 2 meters) was the cause of injury in 20% of skiers and 77% of snowboarders. Neither age nor sex accounted for any significant portion of this difference. The rate of spinal injuries among snowboarders is fourfold that among skiers. Although jumping is the primary cause of injury, it is an intrinsic element of snowboarding. Until research defines effective injury-prevention strategies, knowledge of the risk of snowboarding should be disseminated and techniques for safe jumping should be taught.     

The epidemiology of knee injuries in Iranian male professional soccer players

Detailed injury epidemiology is an invaluable tool for minimising risk associated with sporting injuries. The aim of this study was to investigate epidemiology of knee injuries in Iranian male professional soccer players. In total, 390 soccer players of 16 clubs were studied during one season. A total of 43 injured soccer players were interviewed and 16 team physicians were consulted. All information was collected through standard questionnaires. Furthermore, medical personal prospectively reported time-loss injuries sustained by players over one season and the knee injuries were evaluated. The results showed that in total, from 390 players, 43 of them suffered knee injuries (14.9 per 100 players). The anterior cruciate ligament was the most commonly injured ligament of the knee, in which 12.5% were accompanied by injuries to the medial meniscus and medial collateral ligament. There was a significant difference in incidence of injury between the preferred (62.9%) and non-preferred leg (37.1%). Most injuries were characteristically severe (82.3%). Most injuries occurred in away games (52.94%), mostly in the second half and most commonly in the final 15 min (35.3%). The incidence of non-contact injuries (66.12%) was significantly higher than contact injuries (33.87%). It can be concluded that the incidence of knee injury was high (0.12 injuries per team per match). Injury tends to be more common in match play and mostly at the end of season. Midfielders suffered more knee injuries. Most injuries occurred in the losing teams.     

Effect of Alpine ski boot cuff release on knee joint force during the backward fall

The modern rigid alpine ski boot has been associated with an increase in severe knee joint injuries. A new design that allows the rear portion of the upper cuff of the boot (rear spoiler) to open when a posterior directed force is applied to it (similar to when a skier falls back on the ski) is investigated. Motion analysis was combined with kinetic measures to estimate the shear and compressive forces at the knee joint using a link-segment model while subjects fell backward to provoke ski boot cuff release. The rear spoiler opening was found to reduce anterior cruciate ligament directed shear force while increasing compressive force at the joint. We conclude that both compressive force and reduced anterior cruciate directed shear force have been associated with protective mechanisms at the knee joint. This occurred over a very brief period of time, however, and the influence this may have on knee injury prevention is discussed.     

Anterior cruciate lesions and the protective components of ski bindings]

Serious internal injuries of the knee make up today for the main share of alpine skiing casualties. As well the frequency of such mishaps, as the type of injury and the analysis of how the events happen to unfold, make obvious the requirement for a better protection of the knee joint, and more specifically, of the anterior cruciate ligament. The main role in this regard falls to the ski binding systems. To this end, adding a back fall release trigger, in introducing a vertical elasticity component, may be adequate to avoid the peak strength impulse which acts on the anterior cruciate ligament during an unprotected fall backwards.     

Anterior cruciate ligament injuries in young females playing soccer at senior levels

The aim of this investigation was to study the consequences of anterior cruciate ligament injuries in female soccer players. Special interest was focused on young female soccer players (< 16 years) sustaining anterior cruciate ligament injuries when playing at a senior level, which means playing together with players 19 years or older. In Sweden, all players belonging to an organized soccer club are insured by the same insurance company, the Folksam Insurance Company. Data of all soccer-related knee injuries in females reported to the Folksam Insurance Company between 1994 and 1998 were collected. A questionnaire was sent to 978 females who were registered to have sustained a knee injury before the age of 20 years. The response rate was 79%. Three hundred and ninety-eight female soccer players who had sustained an anterior cruciate ligament injury before the age of 19 years were analysed. Most of their anterior cruciate ligament injuries had been diagnosed using arthroscopy or magnetic resonance imaging (84%). Thirty-eight percent of the players had been injured before the age of 16 years. Of these, 39% were injured when playing in senior teams. When playing in senior teams 59% of the players below the age of 16 years and 44% of the players 16 years or older sustained their ACL injuries during contact situations. At the time of this investigation (2-7 years after the anterior cruciate ligament injury), altogether 78% (n = 311) reported that they had stopped playing soccer. The most common reason (80%) was symptoms from their anterior cruciate ligament-injured knee. It appears that many young female soccer players injure their anterior cruciate ligament when playing at a senior level. Therefore, we suggest that female soccer players under the age of 16 years should be allowed to participate only in practice sessions but not games at a senior level.     

Cross-country skiing injuries and biomechanics

Cross-country skiing exercises most of the joints, muscles and tendons in the body giving the skier an all around workout. This, in combination with a low incidence of injury, makes cross-country skiing an ideal recreational and competitive sport. The new skating techniques developed during the last decade have resulted in greater velocity. The maximum speed during the diagonal stride technique is 6 m/sec compared to 8 to 9 m/sec when skating and double poling. Top-level skiers today use strong and ultra light skis of fiberglass and graphite. The ski weight is less than 500g. Today's skating technique does not require any waxing and only the cambered portion of the ski is waxed when performing the diagonal stride. The preparation of the ski course has improved with the development of special track machines. This allows top-level skiers to reach 60 to 80 km/h on downhill slopes, which has resulted in an increased risk of injury. Because cross-country skiing takes place wherever snow is available, it is difficult to establish accurate injury rates in comparison to alpine skiing which is performed on very specialised terrain at ski areas. Studies estimate the cross-country ski injury rate in Sweden to be around 0.2 to 0.5 per thousand skier days. A prospective study of cross-country ski injuries conducted in Vermont revealed an injury rate of 0.72 per thousand skier days. 75% of the injuries sustained by members of the Swedish national cross-country ski team during 1983 and 1984 were overuse injuries while 25% resulted from trauma. The most common overuse injuries included medial-tibial stress syndrome, Achilles tendon problems and lower back pain. Most common among traumatic injuries were ankle ligament sprains and fractures, muscle ruptures, and knee ligament sprains. Shoulder dislocation, acromioclavicular separation and rotator cuff tears are not infrequent in cross-country skiing. Injuries to the ulnar collateral ligament of the metacarpal phalangeal joint of the thumb (Stener's lesion) is the most common ski injury involving the upper extremity. Cross-country skiers 16 to 21 years of age complained more frequently of mild lower back pain than similarly aged non-skiers. This may result from repetitive hyperextension motions during the kick phase and the recurring spinal flexion and extension during the double poling phase. Repeated slipping on hard and icy tracks infrequently produce partial tears or microtrauma in the muscle tendinous units of the groin.(ABSTRACT TRUNCATED AT 400 WORDS)     

Skiing injuries among Danes in Austria

During the winter of 1986–1987, 1123 skiing injuries among 66,298 Danes in the Austrian Alps were treated by a physician. The male-female ratio was 1.0. The incidence of skiing injuries was 2.5 per 1000 skiers per day; 0.3% of the skiers (84 women and 98 men) suffered a fracture. Significantly more women suffered knee distorsions and ligament injuries than men. In contrast, men suffered more luxations and distorsion of the shoulder, head contusions and tibial fractures than women. Lesions of the thumb were equally distributed between women and men. Preventive efforts should be addressed to the knee, ankle and thumb.