History

The practice of skiing dates back as far as 5000 years ago when early hunters and fisherman used animal tusks to traverse snow. Ski poles evolved from the walking sticks used for balance. Precursors of modern skis have been found in Scandinavia and Siberia, and date back to 2000 bc. However, the first written record of skis is attributed to Chinese historical accounts from ad 600. Competitive skiing started in Norway in 1767, and within 100 years it was a well-established activity in the Scandinavian countries.1 The Olympics of 1924 were held in Paris, France as an honour to and request of the retiring IOC founder and president, Pierre de Coubertin. That same year, the town of Chamonix, France planned a winter sports festival and decided to petition the International Olympic Committee (IOC) to recognise this event. While the IOC did not sanction these games as Olympic Games, they did allow Chamonix to call the events an Olympic Winter Carnival. The surprising success of these games led the IOC to sanction a separate winter set of games, and the Winter Olympic Games were formally established in 1928.2 St Moritz, Switzerland was the host city for these first sanctioned winter games, and nordic skiing comprised the only skiing event. In 1936, alpine skiing first appeared on the programme, but because of World War II, the winter Olympics were not held again until 1948. It was not until the Lake Placid Olympics in 1932 that competitive skiing really began to gain popularity in the USA. The numbers of skiers in the USA continued to increase, and today there are an estimated 15 million skiers of all ages in the USA, 200 million skiers worldwide, and an ever-growing number of snowboarders. According to the national sporting goods association data from 2008, 6.5 million Americans participated in skiing more than once and 5.9 million in snowboarding, both increases from previous years.3 4

Snowboarding is a relatively new winter sport whose history dates back only to the 1920s, and the current style of snowboarding device was first introduced in the late 1970s. The increasing popularity of snowboarding over the past 20 years has continued to increase the number of people using ski slopes, and in 1998 it was made an Olympic event at the Nagano Olympics. Developments in snowboarding include the motocross-inspired discipline, snowboard cross, which was first added to the Olympic programme for the 2006 Winter Olympic Games in Turin. There has also been the introduction of the “super pipe,” a halfpipe with larger dimensions than the traditional halfpipe. The trend towards these types of “big air” events provides new challenges for those involved in the care of these athletes. The upcoming Winter Olympic Games in Vancouver, Canada, will be another chance to advance the fields of skiing and snowboarding on the international stage.

Alpine skiing is a popular sport worldwide which has enjoyed a steady increase in expansion until the early 1990s. The advent of snowboarding has brought new challenges to both skiers and those treating skiing injuries. Understanding the differing injury patterns of skiers and snowboarders, and treating these injuries appropriately can help reduce long-term complications and return participants to sport earlier.

Injuries are relatively common during alpine skiing, with the lower extremity being injured almost twice as much as the upper extremity.5 In contrast, the upper extremity is injured nearly twice as often during snowboarding than in alpine skiing with approximately 50% of all snowboarding injuries involving the upper extremity.6 From epidemiological data estimates, upper-body injuries account for 30 to 50% of all skiing injuries, while upper-extremity injuries account for 20 to 35% of all ski injuries.7 Wrist injuries and fractures are the most common snowboarding injury often occurring as the snowboarder tries to brace themselves from a fall. The most common upper-extremity injury seen in skiers is a sprain of the thumb ulnar collateral ligament at the metacarpal–phalangeal joint, known as gamekeeper’s thumb or skier’s thumb.

When focusing on the shoulder, the most common fracture seen among skiers is of the clavicle, and the most common dislocation is the glenohumeral joint. With the increased ratio of upper- to lower-extremity injuries during alpine skiing and with the booming popularity of snowboarding, shoulder injuries have been seen with increasing frequency by those caring for this population. There has been a decrease in overall lower-extremity injury rates, which contribute to the increase in the ratio of upper-extremity to lower-extremity injuries. Warme et al reported that the ratio of upper-extremity injuries to lower-extremity injuries in skiers increased from 1:4 to 1:2 between 1982 and 1993 when looking at the injuries at the Jackson Hole Ski resort.8 Deibert et al also noted a decrease in the incidence of fractures involving the lower extremities in both children and adults. His study also noted the incidence of upper-extremity fractures increased in frequency in children but remained relatively steady in adults.9

The traditional way of describing ski injury rates was in terms of “injuries per thousand skier days” (IPTSD) where: IPTSD = (number of injuries/number of skier days) ×1000.

The problem associated with using the “skier day” concept continues to be that it assumes that when a lift ticket is bought or a person goes up on a lift, they will be skiing or snowboarding all day. It also does not take into account season pass holders, multiday pass holders, instructors, patrollers and employees. Thus, the actual population at risk may be underestimated. This may contribute to the varied incidence of overall injuries, especially shoulder injuries, seen in various studies. Another equation that investigators have used to assess the incidence of ski injuries is the “Mean Days Between Injuries” (MDBI) equation. According to this equation: MDBI = (skier visits/number of injuries).

The higher the MDBI value, the lower the risk of injury. This equation helps to control for some of the confounding variables which can skew the IPTSD calculation. The limitation of this equation is tied to the fact that it is most accurate when evaluating relatively rare injuries. Both equations have been used and are accepted when reporting and evaluating skiing and snowboarding injuries.

As skiing continues to evolve as a sport, there are clear trends concerning both the incidence and types of injuries being sustained by skiers. When looking at various studies from 1962 to 2008, some conclusions can be drawn about the overall trends of skiing injuries. Over the last 50 years, the number of reported injuries has decreased from 7.6 injuries per 1000 skier days in the 1950s to three injuries per 1000 skier days in the late 1990s and, most recently, 1.9 injuries per 1000 skier days in 2008.9 10 11 12 13 14 15 16 17 18 19 Despite the steady fall in overall skiing injuries, the prevalence of upper-extremity injuries over the past 20 years continues to increase. A major factor in the decreasing incidence of ski injuries is related to improvements in ski equipment, especially boots and bindings. In addition to advances in the designs of skis and ski bindings, the technology of ski poles has advanced to provide increasing stability in a lightweight manner. In this article, we will review shoulder injury patterns during alpine skiing and snowboarding, and discuss trends in both equipment and treatment.

Shoulder injuries in skiing

According to several studies on alpine skiing injuries, trauma to the shoulder accounts for 4% to 11% of all ski injuries (table 1). Kuriyama and associates reviewed 14 952 injuries during 10 seasons in Japan and found that 4.5% of all injuries involved the shoulder.20 Carr and coworkers studied 1711 injuries during one season at a Vermont ski area and found that 6.9% of all injuries involved the shoulder, and 32.4% of all upper-extremity injuries involved the shoulder.21 Of the 1870 shoulder injuries studied by Weaver during the 1978–1979 ski season in Aspen, Colorado, 7.2% involved the shoulder, and the incidence of these injuries was 0.2 injuries per 1000 skier-days.19 Sherry’s study of shoulder injuries looked at 1850 skiing injuries during one season in Australia and found shoulder injuries to account for 10% of all injuries and 27.7% of upper-extremity injuries that year.22

The most common injuries to the shoulder during skiing are rotator cuff strains (24%), anterior glenohumeral dislocations and subluxations (22%), acromioclavicular separations (20%) and clavicular fractures (11%)23 (table 2).

Shoulder injuries in skiing are usually sustained through one of three common mechanisms: an axial load from an out-stretched arm, a direct blow to the shoulder or an eccentric load as the skier resists forced abduction. Shoulder injuries can also result from collisions with people, trees and other fixed objects. Often there are excessive external rotation forces resulting from a fixed ski pole in the hand of a falling skier. Wrist straps on ski poles are often the culprit in shoulder injuries, as the pole can be caught behind the skier while still firmly attached with a wrist strap. The shoulder is then subjected to forced abduction and external rotation, which may result in a glenohumeral dislocation, fracture or other serious upper-extremity injury. The pole acts as an extension of the upper extremity to increase the lever arm and make dislocation of the shoulder much easier. The ski poles can also be caught by any number of objects to create a sudden jerking force on the shoulder which may cause severe injury to both the static and dynamic restraints of the shoulder.24 25 Reduction of a shoulder dislocation and treatment of shoulder injuries should be done in a timely manner to decrease the chance of neuropraxia or vascular injury. Some advocate aggressive arthroscopic stabilisation for those with first-time shoulder dislocations, though most clinicians treat primary dislocations with reduction and physical therapy reserving arthroscopic stabilisation for those who fail conservative measures.

Several studies have shown a high incidence of recurrent shoulder dislocation in the skiers and snowboarders under the age of 40 and particularly for those under 25 years of age at the time of their first dislocation.19 20 26 In the over-40 age group, prolonged morbidity secondary to rotator cuff pathology is the primary concern as the recurrence rate for shoulder dislocations in this demographic around 4%. Pevny et al, examining patients over the age of 40 who had first-time shoulder dislocations related to skiing, found that the incidence of concomitant rotator cuff tear was 35%, increasing to 40% in those who had a greater tuberosity fracture, and 100% in those who also had neurological findings, principally involving the axillary nerve.26 In the review of 70 ski-related glenohumeral dislocations by Weaver and the review of 660 dislocations by Kuriyama et al, all shoulder dislocations were anterior, and only half of the patients in the series by Kuriyama were first-time dislocations. The incidence of minimally displaced greater tuberosity fractures associated with these dislocations ranged from 3% to 10% in these series.19 20 The majority of these dislocations were reduced in the ski medical clinic or slopes without intravenous sedation. These reductions were typically uncomplicated, and this finding was correlated with the common finding that patients experienced minimal pain or muscle spasms if they were seen and reduced within the first hour after dislocation.

Skiers who fall and land directly on their shoulder are at increased risk for sustaining fractures of either their clavicle or humerus. Recent studies evaluating alpine skiers have shown that while the incidence of most upper-extremity injuries has been decreasing, the incidence of these two fractures has been increasing.16

With the general decrease in both upper and lower-extremity injuries, the emphasis on prevention and advances in equipment are having a positive impact on keeping skiers safer on the slopes. The strategies employed to prevent ski-related injuries include discouraging skiers from “pole planting” while moving and the use of poles without wrist straps or detachable wrist straps.27 Some even advocated the use of an abduction external rotation limiting brace to guard against glenohumeral dislocations. Educators are still searching for the perfect educational programme and equipment to prevent shoulder injuries in skiers. Unfortunately, it has proved difficult to create a training programme that is both effective in decreasing injuries and practical for all skiers.

Snowboarding

Snowboarding represents a relatively new sport on the international sports scene. It was introduced as an Olympic sport at the winter Olympic Games in Nagano, Japan in 1998. Since that time, many changes have taken place which have made it one of the most popular winter sports and helped to increase the popularity of the winter X games with such events as the “Halfpipe” and the “Superpipe.” These types of “big air” events, which require aerial acrobatics, and thus large jumps with landing, and falls from significant height, carry an inherently higher risk of injury. These aerial events also carry an increased risk of significant injury which may require surgical treatment. Snowboarding appears to have a similar or slightly higher total injury incidence rate (four to 16 injuries per thousand skier-days) compared with alpine skiing.10 28 29 Common shoulder injuries during snowboarding include glenohumeral dislocations, clavicle fractures, acromioclavicular separations, rotator cuff strains and proximal humerus fractures.

To fully understand the injury mechanisms in snowboarding, one must first have an understanding of the differences in equipment between snowboarding and alpine skiing that may account for the differential in injury patterns seen in these two groups. In snowboarding, the hard-shelled boot is fixed to the board by a metal plate or binding that is non-releasable, whereas soft boots are held to the board by a soft, high-backed, buckle binding that is also non-releasable. Another difference in equipment is that, unlike skiers, snowboarders with their surfer like stance on the board do not use poles. Along with differences in boot, board and binding, the biomechanics of snowboarding are different from those of skiing. Snowboarders stand sideways on their boards, much as skateboarders or surfers do, with the rear foot at 90° to the long axis of the board and the front foot positioned between 45 and 90° to the long axis. Turns are executed by shifting the bodyweight to the front foot and allowing the tail of the board to swing outward.9 30 Snowboarders frequently fall on their backside to buckle and unbuckle their foot with regard to their boots and to take breaks, adding to the risk to the upper extremities. The upper extremities are particularly at risk due to the fixed position of the lower extremities. Upper-extremity injuries account for approximately half of all snowboarding injuries, and there are twice as many upper-extremity injuries among snowboarders than with skiers (table 3).

Several theories exist for why snowboarders have an increased risk of upper-extremity injuries.31 The reason may be related to the fact that when snowboarders fall, they tend to put their hands on the ground in the anteroposterior position because both feet are in boots that are fixed to the board with non-releasable bindings. Snowboarders do not use ski poles either, which may explain the increase in falls onto a hyperextended wrist.32 With the increased number of falls directly on to the outstretched upper extremity, the rates of fractures in the upper extremity tend to be higher in snowboarders compared with skiers. The wrist is 10 times more likely to be injured during snowboarding than skiing, and wrist fractures are the most common snowboarding injury.10 33 There is no consensus as to whether upper-extremity injuries are more common with backward falls towards the heel-side of the board, as opposed to forward falls towards the front of the board.34

In general, the rates of joint dislocations in snowboarding are higher than in skiing except for the shoulder and finger.35 Injuries often occur during jumping or aerial manoeuvres, with a small percentage of injuries associated with chair-lifts and tow bars. Shoulder injuries account for 8 to 16% of all snowboarding injuries and 20 to 34% of upper-extremity injuries.36 Dohjima et al showed distinct differences when comparing specific joint dislocations between the two sports.35 The most common dislocation during skiing was of the shoulder joint, followed by the finger joint, and acromioclavicular joints. In this same study, a significant difference was seen between shoulder dislocations in snowboarders and skiers, 55% versus 79% respectively. Even with recent studies, there is still no consensus, when comparing snowboarding and skiing injuries, as to which has the higher incidence of shoulder injuries.37 38 There is literature to support either sport as having an higher incidence of shoulder injuries, though due to the growing population of snowboarders, changes in equipment and style of skiing and snowboarding, and the advances in the sport over the past 5 years, more consideration should likely be given to more recent studies.39

Discussion

Discrepancies exist when comparing the data concerning types of injuries sustained by skiers and snowboarders. Differences that could account for the varied percentages in the incidence of shoulder injuries throughout multiple studies include differences in study design and methodology, environmental conditions, as well as skier and snowboarder personal attributes, such as skill level, ability and relationship to the terrain. In addition, several studies have noted an increase in the relative percentage of upper-extremity injuries over time. Carr et al, and Sherry and Fenelon also found soft tissue strain to be the most common shoulder skiing injury, whereas Kuriyama et al and Weaver found anterior glenohumeral dislocation to be more common among skiers with the vast majority of these dislocation directed anteriorly.19 20 21 40 The most recent study published by Johnson et al in 2008 showed an increase in clavicle and humerus fractures among alpine skiers.16 Unlike patients with dislocations or fractures of the shoulder complex, patients with soft tissue strains typically showed vague symptoms, subtle physical findings, and variable disability. In fact, rotator cuff strains are likely under-reported because some patients may not have sought immediate medical attention (fig 1).

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Figure 1

Patient with full thickness rotator cuff tear sustained after a fall skiing.

This variability associated with injury reporting may account for the different incidences of rotator cuff strain reported in the literature. The majority of rotator cuff injuries are associated with falls. The suspected mechanism of injury is an abduction-external rotation force against an outstretched arm by the slope during the fall. An alternate mechanism of injury includes direct loading on the shoulder during the fall, suggesting a muscle contusion injury. The one finding that is consistent regardless of the mechanism of injury is pain and weakness, particularly with resisted overhead activties.41

In addition to the variability in injury reporting, the literature also shows conflicting data on whether upper-extremity injuries related to skiing and snowboarding have equal distribution among men and women. Kocher et al and Sasaki et al found upper-extremity injuries to primarily affect male skiers and snowboarders.27 32 However, Carr et al found that men and women were at equal risk of injury with respect to the upper extremity.21 Even though the effect of gender on the risk of injury in snowboarding and skiing is not clear, based on these studies we are able to draw several other important conclusions.42 For example, snowboard riders appear to have an increased incidence of overall injuries and a higher proportion of upper-extremity injuries. The literature points to the fact that there are one and a half to two times more upper-extremity injuries in snowboarding than in alpine skiing.27 37 38

Another difference, unlike snowboarding, where a large percentage of injuries occur on the left side as a result of the regular style with the left foot in front, is that laterality is typically not observed in downhill skiers.35 There are also differences when comparing children and adolescent skiers with adults. Recent studies have reported an increase in the proportion of upper extremity trauma constituting 23–37% of the total number of ski injuries reported in children, excluding injuries to the thumb. Shoulder injuries with associated acromioclavicular dislocations, clavicle and humeral fractures in children account for the majority (22–79%) of upper extremity cases.33 43 44 Although the incidence of adult injuries in skiing has declined due to rapid advances in technology, the incidence of ski trauma in children and adolescence remains high. The highest percentage of injuries occurs from ages 6 to 15 years. The potential risk of trauma is compounded by inexperience, musculoskeletal immaturity and inadequate equipment.45

There is a trend toward more aggressive treatment of shoulder injuries in young, active patients, including skiers and snowboarders. As mentioned above, with arthroscopic techniques, there is a movement to surgical stabilisation of first-time shoulder dislocations, which helps reduce recurrence, often associated with young age at the time of first dislocation. Due to the pain and dysfunction associated with malunion or non-union of clavicle fractures, particularly when comminuted or shortened more than 1.5 cm, there is a trend toward early open reduction and internal fixation of these fractures, particularly in competitive athletes, for earlier return to sport and ensured strength maximisation (fig 2). This has been made easier with precontoured clavicular plates. Rotator cuff repair, particularly for acute ruptures, especially in young, active individuals, continues to be the gold standard of treatment. With arthroscopic techniques for rotator cuff repair, the morbidity and prolonged postoperative pain are minimised, and this is becoming the treatment of choice for the treatment of rotator cuff repair, though the literature has not supported the arthroscopic technique as being superior. One must still consider the techniques equivalent, if the open is not still the gold standard.

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Figure 2

(A) Left clavicle and scapula fracture sustained by a snowboarder who had a fall that resulted in a direct blow to the left shoulder. (B) Radiographs of this patient following open reduction internal fixation of his left clavicle.

Epidemiological investigations of skiing injuries are fraught with inherent difficulties, including ambiguity of injury definition, under-reporting and design limitations. The definition of a skiing injury must be logical and understandable because it can greatly affect the interpretation of data. Too broad a definition can result in over-reporting, with the inclusion of all incidental scratches and bruises, whereas too narrow a definition can result in under-reporting, with the exclusion of significant, morbid injuries. If we chose to define an injury as one that required medical attention from healthcare providers, we will likely underestimate the incidence of some injuries. This definition inevitably leads to under-reporting because some patients do not seek medical care even for significant injuries, some patients seek medical care elsewhere, and some injuries are not immediately apparent. In fact, for some injuries, such as skier’s thumb, it is estimated that only 20% to 25% of the injured patients seek immediate medical care. There are also limitations in reporting the incidence of injuries as injuries per 1000 skier-days.46 47 This assumes that a skier-day is equivalent in terms of the number of hours of skiing, skiing style and level of difficulty, which is almost never the case. Another limitation of analysis of shoulder injuries in these sports is that many articles published on upper-extremity injuries in skiers and snowboarders do not stratify injuries into shoulder, elbow and wrist. The general category of upper-extremity injuries includes many injuries which were not covered within the scope of this article. Future studies may wish to focus on treatment of injuries in skiers and snowboarders, and how aggressive physicians are when treating these injuries. This is especially true of those treating recurrent shoulder dislocations or rotator cuff pathology in this population. Future studies in this field should include gathering information concerning risk factors for shoulder injuries, skier ability, fitness level, equipment and environmental conditions at the time of injury.