Changing injury pattern of acute anterior cruciate ligament tears treated at Tampere University Hospital in the 1980s

During the years 1980–1989, 450 patients with an acute anterior cruciate ligament (ACL) rupture were treated at the University Hospital of Tampere, Finland. ACL ruptures were diagnosed by arthroscopy or open surgery. The data were analyzed in terms of patient age, sex, injury etiology, injury type and sports activity to determine the trends in the 1980s. The number of ACL tears seen in the Hospital increased by 247% over this period. Sixty-three percent of the patients were male (mean age 33 years) and 37% female (mean age 39 years), and there were no changes in the sex and age distribution in 1980s. The most common injury type was the isolated ACL rupture (51%), followed by a combination injury of the ACL and medial collateral ligament (38%). Isolated ACL ruptures in the 1980s increased 6.5 times. Sports accounted for 54% of all injuries with out any sign of change in their relative proportion in 1980s. The most common sports causing the rupture were soccer (29%), downhill skiing (20%), cross-country skiing (12%) and volleyball (12%). From 1980 to 1989, there was a decrease (2 times) in ACL injuries sustained in crosscountry skiing and a substantial (30 times) increase in ACL injuries sustained in downhill skiing.     

Relationship between jump landing kinematics and peak ACL force during a jump in downhill skiing: A simulation study

Recent data highlight that competitive skiers face a high risk of injuries especially during off‐balance jump landing maneuvers in downhill skiing. The purpose of the present study was to develop a musculo‐skeletal modeling and simulation approach to investigate the cause‐and‐effect relationship between a perturbed landing position, i.e., joint angles and trunk orientation, and the peak force in the anterior cruciate ligament (ACL) during jump landing. A two‐dimensional musculo‐skeletal model was developed and a baseline simulation was obtained reproducing measurement data of a reference landing movement. Based on the baseline simulation, a series of perturbed landing simulations (n = 1000) was generated. Multiple linear regression was performed to determine a relationship between peak ACL force and the perturbed landing posture. Increased backward lean, hip flexion, knee extension, and ankle dorsiflexion as well as an asymmetric position were related to higher peak ACL forces during jump landing. The orientation of the trunk of the skier was identified as the most important predictor accounting for 60% of the variance of the peak ACL force in the simulations. Teaching of tactical decisions and the inclusion of exercise regimens in ACL injury prevention programs to improve trunk control during landing motions in downhill skiing was concluded.     

双膝前交叉韧带损伤特点及治疗

目的探讨双膝前交叉韧带(ACL)先后断裂的原因及治疗原则。方法1995年1月~2005年8月收治双膝ACL先后损伤患者32例,对双膝致伤因素、先后损伤之间的关系、膝关节不稳的情况进行观察分析,回顾其受伤到手术的时间及治疗情况。结果32例双膝ACL损伤,运动性损伤占78.1%,后一侧ACL损伤的发生与先伤膝关节不稳、病人的年龄、运动程度有关。89.1%的膝关节在ACL损伤后出现不稳。所有患者均在我院接受ACL重建手术,26例患者双膝ACL重建为一次手术完成,6例分次重建。结果提示一侧ACL断裂引起的膝关节不稳可影响到健侧。膝关节ACL断裂后要早期手术重建以恢复膝关节的稳定性,防止继发损伤,降低另一侧膝关节受伤的风险。对于双膝ACL断裂,我们建议一次手术完成双侧重建,以尽早恢复双膝关节稳定性,保证双膝运动功能。     

The Harstad injury prevention study: the epidemiology of sports injuries. An 8 year study.

OBJECTIVE--To describe the epidemiology of sports injuries occurring in a community during 8 years and to evaluate the outcome of an intervention implemented against injuries occurring in downhill skiing. METHODS--Hospital treated sports injuries occurring in Harstad, Norway (population 22 600) were recorded prospectively during an 8 year period. A prevention programme targeting downhill skiing injuries was evaluated. RESULTS--2234 sports injuries accounted for 17.2% of recorded unintentional injuries. Two out of three injuries occurred in team sports. Soccer accounted for 44.8% of all sports injuries. Downhill skiing injuries had higher mean score on the abbreviated injury scale than all other sports analysed combined (P < 0.01). Postintervention injury rates for downhill skiing were reduced by 15% when adjusting for exposure (P = 0.24). Further observations are needed for assessing the effectiveness of the downhill skiing safety programme. CONCLUSIONS--Strategies for future sports injury prevention include community involvement, particularly sports organisations. Local data analysis seems to justify some priorities, for example, promotion of helmet use in downhill skiing for young adolescents and prevention of lower limb fractures in male soccer players 15+ years old. Prospective hospital recording of injuries provides a tool for the design and outcome evaluation of sports injury intervention research.     

Prior myocardial infarction is the major risk factor associated with sudden cardiac death during downhill skiing

More than 90% of all sudden cardiac deaths (SCDs) during downhill skiing, the most popular winter sport world-wide, are attributed to men over the age of 34. However, no data exist on additional risk factors and triggers for SCD related to downhill skiing. Therefore risk factor profiles of 68 males who died from SCD during downhill skiing were compared to those of 204 matched controls. Skiers who suffered SCD had much more frequently prior myocardial infarction (MI) (41% vs. 1.5%; p<0.001), hypertension (50% vs. 17%; p<0.001), known coronary heart disease (CHD) without prior MI (9% vs. 3%; p=0.05) and were less engaged in strenuous exercise (4% vs. 15%; p<0.05) when compared to controls. Multivariate analyses even enhanced the importance of these risk factors. Downhill skiing is considered to be a serious trigger for SCD especially in skiers with prior MI but also for those with hypertension, known CHD without prior MI, or insufficient adaptation to strenuous exercise. Skiing-related increased sympathetic activity might well disturb the autonomic balance with subsequent arrhythmias and/or may increase cardiac work and platelet aggregability with possible plaque rupture and coronary thrombosis. Therefore adaptation to high intensity exercise and therapeutic interventions or abstinence from skiing in certain cases should be considered for downhill skiers at high risk.     

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)     

Secondary damage to the knee after isolated injury of the anterior cruciate ligament

Between 1978 and 1984, we examined and performed arthroscopy on 1000 consecutive patients. Ninety-eight of the 1000 had isolated ACL damage. These cases do not include patients with initial ACL injuries combined with other intraarticular damage. Diagnosis was by physical and arthroscopic examination. Examination took place an average 13.6 months after injury. Of the 98 isolated ACL injuries, 56 were complete ruptures and 42 were partial ruptures. In most cases of partial rupture, the clinical diagnosis was wrong. "Meniscal damage" was the usual diagnosis in these cases; the true diagnosis was made only by arthroscopic examination. Thirty-four of the 98 patients with isolated ACL injuries (30 men and 4 women) developed further intraarticular damage. Of these 34, 20 had complete ACL rupture and 14 had partial ACL rupture. Treatment after primary injury included physiotherapy in all patients and bracing in those whose knee was unstable during daily activities. Reconstructive surgical procedures were not performed in those patients. The time lapse from the primary to the secondary injury varied from 1 month to 20 years, with an average of 28 months. The secondary damage was caused by a secondary injury that was mild (22 cases) or developed insidiously (12 cases). Five types of secondary damage were observed: partial ACL tears that became complete--11 cases; meniscal tear--8 cases; loosening and subluxation of the anterior horn of the medial meniscus--14 cases; and fracture or damage to the articular condylar cartilage, with or without bone involvement--11 cases. It should be emphasized that the secondary damages were at times combined.     

Contraction of knee flexors and extensors in skiing related to the backward fall mechanism of injury to the anterior cruciate ligament

The purpose of this study was to examine the motion pattern and muscle activity during jumping and landing in downhill skiing to estimate the muscular involvement during the jump-landing-backward fall-anterior cruciate ligament (ACL) injury. A digitized 2-D video motion analysis and a synchronous 8-channel electromyography registration was performed over a jump on a downhill slope during 3 runs by 2 skiers and during 6 control jumps in the laboratory. The knee flexors (lateral gastrocnemius and biceps femoris) were recruited before touchdown and mean 60 ms earlier than the extensors (vastus lateralis and rectus femoris). Extensors and flexors reached peak activity simultaneously at the instant of landing. The knee flexion angle at the instant of landing was mean 36°. As the landing was stabilized, the extensor activity persisted during eccentric work at increasing knee flexion as a corresponding flexor relaxation took place. The control jump in the laboratory showed a similar order of recruitment and timing of muscle contraction. The gastrocnemius was recruited mean 96 ms earlier and the biceps femoris mean 63 ms earlier than the extensors. This recruitment pattern during the landing movement suggest a learned motor program engaging the kinetic chain of the lower extremity to intercept the landing energy. The results also indicate that the knee flexor activity may protect the ACL at the instant of landing but that it is minimal shortly thereafter and probably not able to protect the ACL when a backward fall occurs. The knee was flexed substantially as the extensors became the dominating muscles. Thus, their ability to apply any anterior drawer force able to rupture the ACL is questioned.     

Completion rates and injuries in alpine races during the 1994 Olympic Winter Games

The starting lists for the alpine disciplines during the 1994 Olympic Winter Games in Lillehammer totalled 555 racers, but only 354 of them (64%) completed the different races. The race completion rate was 43% in the slalom, 51% in the giant slalom, 75% in the super giant slalom and 91% in the downhill. In combined downhill/slalom the race completion rate was 60%, but 96% in the downhill and 68% in the slalom part of the combination, respectively. Only three injuries were recorded, all in females. Including the training competitions a total of 1541 runs through the different alpine courses was recorded during the games. This means an injury rate of 1.9 injuries per 1000 runs. For downhill the injury rate was only 1.1 per 1000 runs. If the injury rate is related to the number of skiers who did not finish the race because of falls or skiing errors, the rate was 21.1 injuries per 1000 falls (skiing errors) for all alpine races. In conclusion, the race completion rate was twice as high in downhill as in slalom, and the injury rate was low.     

Occurrence and trends in ski injuries in Norway

OBJECTIVES: To provide an overview of ski injuries in Norway and to describe the changes between 1990 and 1996. METHODS: All ski injuries (7966) treated at four hospitals providing health care to a defined population of about 11% of the Norwegian population were registered prospectively from 1990 to 1996. For this study, 6462 injuries sustained in cross country skiing, downhill skiing, telemark skiing, and snowboarding were selected for further analysis. RESULTS: The relative distribution of ski injuries by type of skiing changed significantly from 1990 to 1996 (p<0.001). Injuries from snowboarding showed the highest relative increase, and those sustained during downhill skiing showed a decline. The proportion of fractures in all types of skiing increased during the study period (p=0.001). The proportion of injuries to knee/lower leg decreased and the proportion to the forearm/wrist/hand increased during the study period (p=0.03). The mean age of the injured skiers differed significantly among the different types of skiing activity (p<0.001): cross country skiers were the oldest followed by telemark skiers, downhill skiers, and snowboarders. CONCLUSIONS: Ski injury surveillance results in early detection of changes in temporal injury trends, allowing timely adjustment of injury prevention strategies. Injuries from snowboarding are on the increase in Norway, warranting more effective injury prevention measures.


     

前交叉韧带损伤的临床流行病学研究

为总结分析前交叉韧带(Antenor cruciate ligament,ACL)损伤的临床流行病学特点,进而指导临床,做好有关预防、诊断、治疗、康复工作,我们回顾性研究了1992年1月～2000年12月在我科住院手术治疗的ACL断裂息者共437例,其中运动员175例(男72例,女103例),非运动员262例(男175例,女87例).对损伤发生率、好发项目、男女性别特点、运动员与非运动员间特点、损伤原因及机制、膝关节不稳发生时间与临床的关系等进行统计分析.结果表明女运动员ACL损伤发生率(58.9%)高于男性(41.1%),尤其在柔道、摔跤项目中更为明显(P＜0.01);在跳箱、跨栏项目中,在校女生ACL损伤发生率较高(P＜0.01);运动员与非运动员的非接触性ACL损伤中女性多于男性(P＜0.05).致伤因素运动员以技术失误为主,非运动员以误伤为主.伤后出现膝关节不稳临床症状的时间为2～3个月.为减轻及防止继发损害,恢复膝关节稳定性,ACL重建术应在伤后3个月内进行.     

ACL injury mechanisms and related factors in male and female carving skiers: a retrospective study

In recreational alpine skiing, ACL injury risk is 3 times greater in females. However, since the introduction of carving skis ACL injury risk seems to have decreased. No study has yet investigated the distribution of ACL injury mechanisms in male and female carving skiers. Therefore, the aim of the study was to investigate potential gender specific differences of ACL injury mechanisms and related factors among carving skiers. In total, 220 recreational carving skiers (59 males and 161 females) suffering from an ACL injury volunteered for this study. Demographic data, skiing ability, equipment related and environmental factors, circumstances and causes for the fall, and type of fall (injury mechanisms) were collected by questionnaire. The forward twisting fall is the most reported ACL injury mechanism in both gender (p=0.672) accounting for 54% of all injuries, although male and female skiers differed significantly with regard to circumstances of fall (p=0.001) and actions when ACL injury occurred (p=0.04). Bindings not releasing at the time point of accident occurred 2.6 times more with females than with males (p=0.005). The forward twisting fall seems to have become the dominant ACL injury mechanism both in male and female recreational skiers since the introduction of carving skis.     

Effect of ski binding parameters on knee biomechanics: a three-dimensional computational study

INTRODUCTION: Downhill skiing is a relatively safe sport, but many potentially avoidable injuries do occur. Whereas tibia and ankle injuries have been declining, severe knee sprains usually involving the anterior cruciate ligament (ACL) have increased from the 1970s to the 1990s. The goal of the present study was to evaluate the effect of the position of the binding pivot point and binding release characteristics on ACL strain during a phantom-foot fall. METHODS: We computed ACL strain using a biomechanical computer knee model to simulate the phantom-foot ACL-injury mechanism. This mechanism, which is one of the most common mechanisms of ACL injury in downhill skiing, occurs when the weight of the skier is on the inner edge of the ski during a backward fall, resulting in a sharp uncontrolled inward turn of the ski. RESULTS: The model predicts, that under simulated phantom-foot conditions, a binding with fast-release characteristics with a pivot positioned in front of the center of the boot produces less strain on the ACL. Current bindings have their pivot point approximately at the center of the heel radius. A pivot positioned at the back of the binding is more effective for sensing loads that occur at the tip of the ski. However, it is less effective for sensing loads that occur at the tail of the ski and, therefore, offers less protection during a phantom-foot fall. CONCLUSION: A binding with two pivot points, one positioned in front and the other at the back, could sense twist loads applied to the ski both at the front and at the back, and might, therefore, be a solution to reduce the occurrence of ACL injuries.     

Anterior cruciate ligament injuries in snowboarders: a quadriceps-induced injury

Anterior cruciate ligament (ACL) injuries in snowboarders are rare. However, in expert boarders landing big jumps, ACL injuries are occurring more frequently. We identified 35 snowboarders with an identical injury mechanism. All these patients were landing from a jump. All described a flat landing on a flexed knee with significant knee compression. In 31 of 35 boarders, it was the front knee that was injured. Only two riders felt there was any twisting component to their injury. We postulate that the ACL rupture is due to maximal eccentric quadriceps contraction, as the boarder resists a compressive landing. Internal tibial rotation of the front knee in the snowboarding stance results in preloading of the ACL predisposing to injury.     

Downhill skiing injuries and their cost at a Finnish skiing area

During the 1987–1990 ski seasons. 325 consecutive patients sustained downhill skiing injuries at a skiing area in central Finland. The calculated injury rate was 0.94 per 1000 skier-days (0.9%) and 0.56 per 1000 skiers (0.06%). Forty-one percent of the injuries were located in the lower limbs and 37% in the upper limbs. Sprain was the most common type of injury (34%), followed by fractures (22%) and contusions (17%). Only 7% of the patients needed surgery. The estimated mean cost of medical treatment and sick leave was FIM 5500 (USD 1400) per patient.     

Skiing safety in children: a prospective study of downhill skiing injuries and their relation to the skier and his equipment

A prospective analysis was made of 31 children who sustained an injury of the lower extremity during downhill skiing. They were compared with a control population of 183 skiers. The injured children were to a large extent less skillful skiers and tended to be injured at the start of their skiing season. In general, the risk of having an injury did not seem to be influenced by the question of where or by whom the bindings were adjusted. Nevertheless, beginners predominantly had had their bindings adjusted in ski shops. The heel mechanism functioned well in most cases, while the function of the toe mechanism was poor in the control population and even poorer in the injury group. The results indicate that many of the present release bindings used by children are of poor quality and should be improved. At present, a reasonable recommendation for children should be to set the heel mechanism according to the standard scale and the toe mechanism as loosely as possible without having a release during ordinary skiing. Increased use of testing devices is advocated. In Sweden, improved education of personnel in ski shops, with the children in focus, seems important, and training and supervision of the beginners should be intensified.     

Ski-flying: related catecholamine excretion compared with cross-country skiing

We examined the catecholamine excretion and its performance-diagnostic relevance in athletes of the German National Team during ski-flying and cross-country skiing. Five athletes were examined during the 1986 World Championship ski-flying competition and eight athletes during a 24-km cross-country qualification test. There is little doubt that the special competitive conditions have considerable influence on the usefulness of these data. We decided to publish the results anyway since the results may expand our knowledge about the performance-diagnostic relevance of catecholamine excretion under competitive conditions. During cross-country skiing, the average noradrenaline elimination (1166 pmol.min-1) was about 150% higher and the average adrenaline elimination (243 pmol.min-1) about 30% lower than during ski-flying. The noradrenaline-adrenaline ratio was about 4.8 in cross-country skiing and 1.3-1.5 in ski-flying. Catecholamine excretion does, as expected, therefore permit differentiation of the various strains on the organism. The impression with respect to performance-diagnostic relevance arises that successful athletes show a more stable and lower excretion of noradrenaline under competitive conditions. This can only be a preliminary statement; it should serve to stimulate discussion and further investigations of the problem.     

Extra-articular tenodesis for anterior cruciate ligament rupture in amateur skiers.

Thirty one amateur skiers with 33 knees which had had a symptomatic chronic rupture of the anterior cruciate ligament (ACL) treated with the Lemaire operation were reviewed retrospectively at an average of 4.5 years. Of the patients 23 were women. The operation failed to control symptoms in 17 out of the 33 knees. However the operation did control symptoms in 13 out of 19 knees in patients over 35 years old, compared with only three out of 14 knees in patients under 35 years old. Clinical and objective testing however showed that most knees were still unstable. Despite this 21 patients continued skiing. One patient with a successful result switched to playing tennis. Five patients gave up all sports. Four further patients, all under 35 years old, returned to skiing after an additional intra-articular reconstruction of the anterior cruciate ligament. An isolated extra-articular procedure in amateur skiers under 35 years old with symptomatic chronic ACL rupture is not recommended. They need at least an intra-articular reconstruction to control their symptoms and to stabilize the knee.     

Etiology and pathophysiology of tendon ruptures in sports

Of all spontaneous tendon ruptures, complete Achilles tendon tears are most closely associated with sports activities (1–3). Schönbauer (3) reported that 75% of all ruptures of the Achilles tendon are related to sports. In Plecko & Passl (2) the number was 60%. In our material of 430 cases, the number of sports-related Achilles ruptures was very similar (62%), while only 2% of ruptures of other tendons were sports-related (P<0.001) (1). Also, the majority of Achilles reruptures occurred in sports. The ruptures occurred most often in soccer (34%), track and field (16%) and basketball (14%). The distribution of Achilles ruptures according to different sports varies considerably from country to country, according to the national sport traditions. For example, in northern and middle Europe, soccer, tennis, track and field, indoor ball games, downhill skiing, and gymnastics are the most common; and in North America, football, basketball, baseball, tennis and downhill skiing dominate the statistics (1, 2, 4). In sports, some Achilles ruptures are not spontaneous or degeneration-induced but may occur as a consequence of the remarkably high forces that are involved in the performance (2). Ruptures in the high jump or triple jump are good examples. In such cases, failure in the neuromuscular protective mechanisms due to fatigue or disturbed co-ordination can frequently be found. The spontaneous complete rupture of the supraspinatus tendon of the rotator cuff does not occur very frequently in sports. Those sports that include high-energy throwing movements, such as American and Finnish baseball, American football, rugby and discus and javelin throwing, may, however, produce this injury. Partial tears and inflammations of the rotator cuff complex are much more frequent in throwing sports. The complete rupture of the proximal long head of the biceps brachii tendon is rare among competitive and recreational athletes. In our material, under 2% of these ruptures were associated with sports activities (5). The rupture (avulsion) of the distal tendon of the biceps muscle is rare. In sports, gymnastics, body building and weight lifting have been said to be able to produce this injury (6). In general, complete ruptures of the quadriceps tendon and the patellar tendon occur most often in older individuals. In our study, the mean age of these patients was 65 years (5). However, these injuries do also occur in younger age groups, especially in athletes. In athletes, the rupture most frequently occurs in high-power sports events, such as high jump, basketball and weight lifting, at the age of 15-30 years. A chronic patellar apicitis (jumper's knee) may predispose rupture of the tendon (7). As is the case with the rotator cuff complex, overuse inflammation and partial tears of the quadriceps and patellar tendons are one of the most characteristic athletic injuries. Complete spontaneous ruptures of other tendons in sports are rare, although the literature does provide case studies from almost every tendon the human body possesses (8–18).     

运动员与非运动员前交叉韧带断裂后继发膝关节软骨损伤的临床对比研究

目的通过对21例运动员与43例非运动员膝关节前交叉韧带(ACL)断裂后并发膝关节软骨损伤的观察,分析探讨其损伤继发关节软骨损伤的原因及规律。方法应用膝关节镜观察关节软骨损伤的部位、病理改变、损伤程度,然后对损伤发生率、发生时间、损伤程度与病程的关系进行对比研究。结果软骨损伤总发生率为75%,运动员组为66.7%,非运动员组为79%,非运动员组软骨损伤发生率明显高于运动员组(P＜0.01),病程超过1年后关节软骨损伤明显加重(P＜0.01),但两组间差别不显著(P＞0.05)。结论运动员与非运动员ACL断裂后膝关节软骨损伤率明显增高,损伤程度随病程延长而加重。ACL断裂后继发关节软骨损伤的主要原因是膝关节不稳。