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The European Perspective

1999; Lippincott Williams & Wilkins; Volume: 31; Issue: Supplement Linguagem: Inglês

10.1097/00005768-199907001-00001

1530-0315

Domhnall MacAuley,

Injury Epidemiology and Prevention

The ankle may be the same anatomically on both sides of the Atlantic, but we inflict different injuries through different sports. Baseball, American football, and ice hockey may attract small bands of loyal enthusiasts but are not major sports in the United Kingdom. Association football (soccer) and rugby football, cricket, and field hockey are much more popular, and these sports have their own individual injury pattern determined by the nature of the game. Just as the games vary, the research literature and clinical practice also differ. EPIDEMIOLOGY OF ANKLE INJURY Nicholl and his colleagues (15) carried out a national study of exercise-related morbidity in England and Wales using a postal questionnaire sent to 28,857 adults aged 16-45 yr. Soccer accounted for 28.9% of exercise-related injury, and no other activity accounted for more than 10%, although the relative risk of a significant injury in rugby football was three times greater than in soccer. The most frequently reported injures were sprains and strains of the lower limbs, and 11.5% of injuries were to the ankle. These figures can be compared to an earlier study of accident and emergency department attendance (1) which found that 34% of injuries were due to soccer and 24% due rugby football. Cricket was responsible for 4.8% and field hockey for 2.5% of injuries. In this study, ankle injuries were the cause of 14.8% of all attendance. In a smaller but more recent study of accident and emergency attendance of adults over 16 yr (3) of which there were 177 related to soccer in a 3-month period, most injuries were to the lower limb (70%), of which 39 (22%) were ankle sprains with 5 other ankle injuries. Soccer may be the most common cause of sports-related injury attendance in the United Kingdom, but soccer also accounted for 44.8% of all 2234 sports-related injuries in one center in Norway (25). Patterns of casualty department attendance differ in different countries depending on the local sport habits. The pattern of accident and emergency department attendance for children in Australia (7), for example, shows that Australian football and cycling are responsible for more attendance than soccer and rugby. Soccer is the most popular game in Britain and although it is also the most common cause of sports-related attendance at accident and emergency departments this may reflect the popularity of the sport rather than the risk of injury in the sport itself. Rugby football is also a major cause of sports-related injury in the United Kingdom, and in prospective cohort study of rugby injuries in 1705 schoolboy players and 1216 Club players in Scotland (11), 126 (7.4%) schoolboys and 290 (24%) club players experienced injury during a match. Of these injuries, 12 were to the foot or ankle in schoolboy players and 29 in club players. Similarly in New Zealand (2), where rugby is considered to be the national sport, the incidence of ankle injury was 5% in games and 14% of practice injuries. The lower limb was most often injured in games (42.5%) and practices (58.4%) and sprains and strains were the most common injury in games (46.7%) and practices (76.1%). During the prequalifying tournament for the Rugby World Cup held in Kenya in 1993, there were 3 ankle injuries from of a total of 47 recorded injuries (24). Rugby, of which there were two codes, Rugby Union and Rugby League, is essentially a winter game, and it may be that ankle injury is related to the nature of the playing surface. In a fascinating experiment, Rugby League recently changed its entire playing season from the winter to a summer. Unfortunately, from an epidemiological perspective, we have little national data but in a study of one professional club (8), the injury pattern changed and, although the numbers were small, there was an increase in the rate of joint sprain from 10.5 per 1000 h of play to 20.1 per 1000 h of play. The authors had previously recorded an overall rate of 9 ankle joint injuries per 1000 h of play in Rugby league in a different study (20). This suggested that the increase in injury may be due to the harder playing surface and may parallel the increase in injury rates associated with Astroturf fields in American football (16), where there was an increase in knee (1.18) and ankle injury (1.39). SPORT-SPECIFIC INJURY Some injuries are so common in a sport that they become identified particularly with that sport. Smith (19) recently reminded us of "footballer's ankle," which is a soccer injury. The condition was originally described by T. P. McMurray (13) of Liverpool, England, in an article published posthumously. He suggested that the injury occurred because, in soccer, the kicking foot is held in full equinus causing strain on the anterior capsule, leading to the development of an osteophyte on the anterior tibia. Although an osteophyte suggests osteoarthritis, the remainder of the articular surface was normal. Smith reminds us that in soccer the average kicking velocity is 96 km·h−1 and that during a match each player may kick on 60-120 occasions. In a recent prospective study of this injury from Amsterdam (22), there were 62 patients of which 24 were soccer players. Although most professional footballers can return to play 4-6 wk after arthroscopic surgery and the short-term results are good, the long-term outcome is not known. This osteophyte can occur in other sports, and in a more recent paper from Seattle (18), anterior tibial spurs were described in American football players, baseball players, and ballet dancers. Soccer is also closely associated with the tibial diaphyseal fracture, known as the "footballer's fracture". One hundred consecutive adult soccer players with a tibial diaphyseal fracture attending Leicester Royal Infirmary in England were followed prospectively (5). Details of the circumstances and mechanism of injury were collected and these patients were followed up long term. Only five patients had simple spiral fractures caused by pure torsion, and the remainder (95%) reported an impact as the mechanism of injury mostly (56.5%) resulting from a kick on the shin from in front. These were caused by impact during a tackle and reflect the nature of the game and not necessarily foul play. Protective equipment is important in preventing injury, but an interesting finding was that 85% of players were wearing the appropriate shin guards. The shin guards were damaged by the impact in 17% of cases. The Federation International de Football (FIFA) rules state that shin guards should be worn during club games. Of those not wearing shin guards, only one had disregarded the regulations, and all the others were playing causal games or training, suggesting good compliance with the regulations. One of the challenges facing the clinician is when to advise the player to return to sport after a fracture. Alan Shearer, a key player in the England World Cup soccer squad, returned to play shortly before the 1998 World Cup finals, much to the relief of the fans. David Muckle, a specialist in soccer injuries, describes some of the issues surrounding return to play (14). He pointed out that most sports fractures are internally fixed with screws and plates but that firm fixation means little callus, the fracture cannot be stressed clinically, and magnetic resonance imaging (MRI) or DEXA are inconclusive or impossible. Ideally, the fixation is removed at 3 months with full activity commenced 5 months and the player match fit by 9 months. Return to sport is a matter of clinical judgment and will depend as much on the sport as on the surgeon. Players with indwelling fracture implants may be able to make an early return to contact sport in some selected cases, as illustrated by a recent study of rugby players in Wales (6). Fifteen players were identified who had returned to competitive rugby union with retained fracture implants. Of these, there were four who had fibular plates and two had tibial nails. It is a small study that includes only four ankle injuries, but it does introduce the possibility that some players may be able to return to contact sport. THE ANKLE SPRAIN Ankle ligament injuries are common in sport. Renstrom and Konradsen (17) in their extensive review describe the anatomy, biomechanics, mechanism of injury, diagnosis, grading, treatment and long-term rehabilitation of ankle ligament injury. Diagnosis in the early postinjury phase is difficult as there is pain, swelling, and discoloration and it is difficult to perform an anterior drawer test. They recommend, as suggested by van Dijk et al. (21), that the physical examination be delayed 4-5 d after the initial injury. At this time, the specificity and sensitivity of delayed physical examination for the presence or absence of a rupture of the ATFL were found to be 84% and 96%, respectively, and irrespective of the experience of the examiner, the assessment was as good as arthrography. The key to management is early mobilization, and in grade I or grade II ankle sprains, functional treatment including early motion and the use of an ankle support is the accepted treatment. For grade II injury, the decision is between surgery, cast immobilization, or early mobilization. A review by Kannus and Renstrom recommends functional treatment (10). For the athlete, the most difficult problem after acute ankle sprain can be the residual disability. Many return to sport before fully rehabilitated and suffer long-term problems. The residual chronic ankle instability can be subdivided into mechanical, functional, and subtalar instability and the sinus tarsi syndrome. In their review, Renstrom and Konradsen accept that proprioceptive training is based on empirical data, but it is standard practice and appears to produce good results. There are two main theories used to explain recurrent ankle sprains: the functional instability theory, which is associated with proprioception, and the mechanical instability theory. There is still some confusion in the literature and there is some evidence, from a study of gymnasts, suggesting that stability on single leg standing over a chronically sprained ankle may not be impaired (9). Taping and strapping is not practiced widely. Pragmatists point out that taping is unlikely to influence the biomechanical stress on the ankle joint of an 80-kg man travelling at 15 mph, notwithstanding the potential proprioceptive benefit. Callaghan (4) in his recent systematic review explored the role of ankle taping and bracing in the ankle. He suggested that both the mechanical and functional stability of the ankle can be improved with taping and that as much of the restrictive effect is lost after short bouts of exercise, the neuromuscular and sensory mechanisms may be more important. Athletes are sometimes concerned that taping or bracing may affect performance, and there is some evidence from a recent study in elite Scottish badminton players (12) who took part in a study to investigate the effect on athletic performance and range of motion. Unilateral bracing had no effect on performance, but bilateral bracing impaired some key movements associated with the game. These devices did reduce inversion and could potentially reduce inversion injuries associated with the game but some aspects of performance could be adversely affected by the bracing. SUMMARY Specific information on the incidence of ankle injury is not easy to establish, and studies use variable methodology and recording systems. There are problems in recording injury in many sports injury studies (23) as we often cannot calculate the relative risks without denominator data. Although we can estimate that ankle injuries make up about 10-15% of sports-related injury and that soccer and rugby are responsible for most sports-related injury in the United Kingdom, it is difficult to be more specific. Prevention and treatment strategies are also different, and taping and strapping is not widely practiced. Soccer has a particular injury pattern with some injuries particularly associated with the sport.