LATEST RESEARCH NEWS

A summary of the research presented at the 17th International Symposium of the ISSS held in Aviemore, Scotland in May 2007.

The latest biannual ISSS symposium was held in May 2007 in Aviemore - the home village of www.ski-injury.com - here in the heart of the Scottish Highlands. ISSS meetings bring together researchers from ski areas worldwide to share knowledge and research findings in the area of alpine sports injuries. Specialist fields include epidemiology, orthopaedics, biomechanics, engineering, psychology and more! Hot topics in recent years have included debate regarding current standards for ski binding settings, the issue of helmet and wrist guard use and the biomechanics of snow sports equipment.

This page attempts to present a summary of the main research presentations from this symposium. I am not commenting on every paper but concentrating on those that present findings of interest to a general audience. I apologise if I offend any colleagues I don't mention who presented papers! In time, the other pages of this website will be updated in detail with more specific information. I have grouped the information together under the topic headings laid out below and will continue to add to this page over the coming weeks.
 

Injury rates

The 2007 ISSS conference had a whole day devoted to injury statistics. I recommend you visit my injury studies page (if you haven't already) - it'll explain all about the various studies and statistics I'm about to discuss. Updates were presented from around the world. As ever,  I was amazed how similar injury rates are no matter where in the world you go and look. The current approximate injury rates have not changed significantly in the last few years and are (expressed as injuries per 1000 participant days) 1-2/1000 for alpine skiing and 3-4/1000 for snowboarding and skiboarding. The one country that has reported higher injury rates than other countries (at the last 3 ISSS meetings now) is Greece. The overall injury rate there for snow sports is currently 6.05 injuries per 1000 participant days. Remember that this is still less than 1%!! The actual pattern of injuries seen is similar to elsewhere in the world. The increased injury rate has been attributed to poor skier/boarder education, crowded slopes and antiquated equipment. My good friend Dr Zacharopoulos is to be congratulated for the excellent work that he has been doing in Greece in order to improve the injury risk in Greece. In Scotland, the latest injury data shows an overall injury rate for snow sports of 2.24 injuries per 1000 skier/boarder days. Since we first started our study in 1999/2000 we have seen a year on year decrease in the overall injury rate - the current rate is 66% lower than that in 1999!

 

Injuries in snow parks

The country with undoubtedly the largest injury database in the world is France, a country with nearly 9 million skier/boarder visits per year. The Medicins de Montagne (MdeM) group have collated an impressive database of over 435,000 injuries. Bernard Audema from Avoriaz on behalf of MdeM presented the first data I am aware of looking at accidents occurring in snow parks. They found that 2.8% of all winter sports accidents in France occur in a snow park. 64.6% of these injuries occur amongst snowboarders - this equates to 7% of all injuries seen from snowboarding. Their key findings comparing snowboarders injured in snow parks to all other injured snowboarders were:

  • Snow park Injuries were more likely to be severe
  • Snow park Injuries were less likely to affect the wrist joint (normally the number one injury       area amongst boarders)
  • ACL injuries were more frequent in snow parks
  • More boarders injured in snow parks required admission to hospital


Perhaps not surprisingly, this interesting study lead to a lot of debate about snow park safety, and I will touch on this some more further down this page.
 

Injury surveillance amongst elite skiers and boarders

Tonje Florenes from Norway introduced the newly established FIS Injury Surveillance System (FIS ISS). The system is designed to provide more information on the incidence and patterns of injury occurring amongst elite skiers and boarders on the FIS circuit. Hopefully in the near future it will provide us with some interesting data on this group - their preliminary studies have already highlighted a lack of reporting of injuries amongst elite skiers and boarders .
 

Collisions on ski slopes

In the first large scale study of collision injuries, the French MdeM group analysed 163,000 snow sports injuries. They found that more than 10% of all injuries were caused by collisions between individuals on the slopes. These injuries tended to be of greater severity compared to non-collision injuries. For example:

  • The incidence of head injuries was 3.25x higher
  • The incidence of injuries to potentially dangerous areas of the body (head, chest and spine) was  twice as high
  •  The rate of hospitalisation was 1.5x higher than for non-collision injuries.


Interestingly, this study also showed that since 1992, the risk of a collision with a static object (such as a ski fence or pylon) had decreased by a third, whereas the risk of a collision between individuals had increased. They found a higher risk of these injuries amongst children aged <11 and adults aged >55. The most common type of collision by far was a snowboarder hitting another snowboarder.

This finding is in agreement with other studies (our own in Scotland included) - in general, despite the common perception that some skiers have that boarders wipe them out, the facts show that snowboarders collide with snowboarders and skiers collide with skiers!

The final point made by the French was the need for skilled medical attention whenever a serious collision occurs on the slopes. Certainly it is my experience on the slopes that collision injuries are the most serious we deal with on the ski patrol. Loss of consciousness and multiple injuries are not uncommon when two people collide at high speed and careful attention to the ABC's and the spine are essential.

Bindings


Ski bindings

ISSS 2007 saw the unveiling of a new protype ski binding, developed by Rick Howell and his team at KneeBinding Inc in Stowe, Vermont. Rick has been working on a binding that may help to prevent ACL injury in the phantom foot scenario (see my knee injury page for a full description of this). Rick's work has shown that in the PF scenario, the torque (or twisting force) about the tibia (shin bone) in the lower leg approached zero. Since present ski bindings only sense torsion about the tibia, they are not able to sense and react to a PF fall and release in order to protect the knee. However, his work has shown that the torque about the femur (thigh bone) in these same situations is quite large. Previous work by others has shown that this force is sufficient to rupture the ACL. He has now developed a ski binding that can uniquely respond to force about the femur at force loads below the level that could rupture an ACL. As such, it is the only ski binding to offer sideways release at the heel. Importantly, the binding has undergone on slope testing which has shown no increased tendency to inadvertent pre-release (i.e. the binding releasing when you don't want it to!). For more information, including a video presentation, visit www.kneebinding.com.

Snowboard bindings

The big debate in the world of snowboard bindings just now revolves around the issue of releasable bindings, and whether they would be of benefit to the majority of snowboarders. I have already discussed this topic in some depth on the snowboard FAQ page, but its worth mentioning it here as well. The first thing to be absolutely clear about is that the situation on a snowboard cannot be directly compared to that on skis. Release bindings on skis were developed after it became apparent that excessive numbers of skiers were breaking their lower legs as a result of twisting falls. And they have been successful - since they were introduced there has been a huge reduction in the number of lower leg fractures seen amongst alpine skiers. But we don't see many lower leg fractures amongst snowboarders - the mechanisms of injury on a board are completely different. So its not (as it was with skis) a case of "put release bindings on them and the number of injuries will drop".

The three main arguments put forward for release binding on a board are:

  1. They may help reduce upper limb injuries that occur as a result of a 'fly swat' fall - when a board edge catches and stops and the rider's upper body is then propelled towards the ground at high speed. (This is especially common amongst less experienced boarders). The idea is that if the binding could release in many of these situations then the boarder could just 'walk forwards' rather than falling forwards.
  2. They may help in the situation of a Non Avalanche Related Snow Immersion Death (a.k.a. 'NARSID' or tree well situation - see the section on fatalities on the overview page for more information on what this horrendous way to die is all about. This would only work if - and its a pretty big if - a snowboarder is able to actually trigger the release mechanism on their bindings - whilst often hanging upside down in the tree well.
  3. They may help reduce the incidence of injury when only one leg is attached to the board. This might result for example from an awkward chairlift dismount when the snowboard catches and twists the leg still attached to the board - which is effectively acting as a fat ski.

Against this are the following arguments:

  1. Non-release bindings prevent runaway boards - given that many boarders still do not use leashes, this plays an important role in preventing injuries not only to the boarder but to innocent third parties
  2. Fallen snowboards act as 'snow anchors' and prevent boarders sliding down the piste or, worse still, into trees. This is one reason why it is thought fatalities amongst snowboarders are so much lower than amongst skiers, who regularly fall, slide a long distance picking up speed as they go and then ultimately hit a tree or other static object (sometimes another person).
  3. When one foot is released from the binding (which might happen if both feet are attached and then one binding does release), a boarder effectively becomes a skier with one hell of a fat ski on one leg - this would lead to more twisting knee and lower leg injuries amongst boarders
  4. The mechanics of a binding are such that they generally need rotation (twist) in order to release. For a snowboard, they would also have to release in the direction of the fall (such as catching an edge). Leading binding biomechanical engineers have commented previously that this could be a big problem in terms of designing a binding that fulfil these tasks safely.
  5. Tree well deaths are extremely rare (less than 5% of all traumatic snow sports deaths in the US). The majority of snowboarders will never be susceptible to such a situation. Even if it happens, it is truly questionable whether a boarder could manage to release him or herself from their bindings whilst suspended inverted in the tree well - skiers (who do have release bindings) have also died in tree wells having been unable to release their bindings.

One of the problems for those boarders and manufacturers who advocate release bindings is that to date there is little scientific or epidemiological evidence to support their use. Some manufacturers have claimed that studies  Now, one must remember that this doesn't necessarily mean they don't work, its just that the evidence is lacking and is badly needed. Fortunately, some of the smart cookies in the world of snow sports engineering (Prof Chris Brown in Worcester, MA to name but one) are now looking at some of the engineering challenges presented by release bindings on a board - so watch this space! I would appreciate any comments on this issue, which I believe is gearing up to become a new hot potato in the snow sports injury world.

Protective equipment


Helmets

Not too much completely new information on helmets this time round, but rather consolidation of what we already knew. For a start, there is general consensus now that helmets do offer a degree of protection against injury, but their main protective effect would appear to be mostly in relation to more minor injuries such as abrasions and contusions. The problem remains is that if you slam into a tree or other stationary object at the typical speed of an intermediate skier/boarder, there is not a lot that a helmet can do to protect you.  Such accidents are the usual cause of traumatic deaths on the slopes and the incidence of these accidents remains static, despite increasing numbers of skiers and snowboarders wearing helmets.

The latest data from Switzerland makes for some interesting reading. Data from the Swiss Council for Accident Prevention (for some reason abbreviated to "bfu") shows that nearly 30% of people on the slopes in Switzerland now wear a helmet. The bfu spends just under £100,000 annually on their "Enjoy Sport - Protect Yourself" campaign which promotes helmet wear on the slopes. They reckon that every Swiss franc invested in the prevention of head injuries from snow sports brings an economic benefit of more than 2 Swiss francs - due to the calculated number of head injuries (and their associated costs) the campaign has prevented. If only someone in the UK had the foresight to invest some money here, we too might start to reap more benefit from an accident prevention campaign on the slopes....

Finally on this topic, Irv Scher from the US presented some more excellent simulation work using anthropomorphic test devices (ATD) - crash dummies to you and me - looking at the possible stress on the neck of a child when they fall wearing a helmet. Because the weight of a helmet is a greater percentage of head weight in a child, there has always been some concern that the additional weight of the helmet may increase the risk of potentially serious neck injuries in this age group. Its not something we have seen as ski patrol and happily Irv's work now confirms scientifically that helmets reduce the risk of head injuries in children without increasing the risk of serious neck injuries.

So the take home message remains, wear a helmet, but don’t think it makes you invincible – you still need to ski and board with care and watch out for trees. If you do decide to buy a helmet, look at the label inside and make sure it meets one of the approved standards for snow sports – EN 1077, ASTM 2040 or Snell RS98.

Wrist guards

Much more new information though on wrist guards (WG). The consensus for the last couple of years has been that WG have the potential to reduce the incidence of wrist fractures amongst snowboarders. Data was presented from several countries confirming this important finding. However, two big problems remain:

      ► Sorting out which WGs will offer the best protection and then
      ► getting boarders to wear them!

a) Unlike helmets, there are still no international standards for WG which makes it difficult for a boarder to know if the guard they see and buy in a shop will in fact do the job. An interesting study from France during the 2006/07 season reported at ISSS 2007 involved 20 ski area doctors from the Medicins de Montagne network. They compared the type of wrist guard worn by two groups of boarders - the first group was 341 snowboarders with an injury that could have been either caused or prevented by WGs (wrist, forearm and elbow injuries). They were compared to a group of 586 boarders with any other type of injury who acted as the control group. In both groups, the use of WGs was recorded, as was the type of WG used. The results showed an association between short, rigid WGs worn on the palm side of the wrist with injuries to the wrist, forearm and elbow. There was no difference between WG integrated into gloves compared to WG worn over or under gloves. These findings do not show a definite direct relationship between a short, rigid palm side WG and an increased risk of injury but this finding is in keeping with previous observations from ski area doctors and merely reinforces the advice I have had posted on this site for a few years now which can be summarised as:

  • Wear WG - they do work and are well worth the money. With modern designs, you should be able to find a guard that suits and fits you
  • When looking for a guard, try and buy one that is not rigid, extends up the forearm and ideally sits along the back of your hand and wrist, not under your palm
  • At the end of the day, a WG per se is still probably better than no WG at all.


The ISSS continues to press hard for the standards bodies (such as ISO, ASTM and Snell) to look into the really important issue of WGs. There are currently two wrist protection devices on the market developed by ISSS doctors – the Flexmeter and Biomex protection (found in Level gloves). Both of these are to be recommended and you can find more information on my wrist injuries page.

b) So if WGs can reduce the incidence of the number one injury amongst boarders – why don’t more boarders wear them? Rates of WG use vary between countries, but are usually in the range of 10-20% at best. Research from both Switzerland and Scotland has identified some of the possible reasons, including concerns about comfort and fear of injury from the WG itself. This is an important point that is frequently cited as a reason not to wear WG - that by so doing the fall energy is simply transferred up the arm leading to an injury further up - perhaps at the elbow or shoulder. In fact if you look at the evidence from all the studies that have been carried out, this does not seem to be the case which is reassuring.

So in summary, the general idea of wearing wrist guards is recommended – they are not expensive but could prevent a nasty injury that will prevent snowboarding for many weeks, months or longer.
 

Snow park jump design

Several presentations covered the design of jumps in snowboard parks, stimulated in no small way by a recent multi-million dollar damages award to a snowboarder injured as a result of a jump that went badly wrong. The rather surprising bottom line is that no design standards exist for snowboard jumps - you just build a ramp that looks about right, and then let the boarders get on with it. Now that one of those boarders using such a jump has been injured and awarded massive damages against the ski area, all of that is likely to change! The challenge is to design jumps that are safe, and yet not boring. Snowboarders (and skiers for that matter) love to jump for many reasons - the challenge and exhilaration involved are but two of these. Take them away though, and all the fun goes out of jumping. So it seems clear that the design engineers, snowboarders and perhaps even the lawyers need to sit down to bash things out. Just remember for now that when you take off from that jump or ramp that chances are high that the person who built it probably has no idea where you are likely to land or how.
 

ISSS 2009


The next ISSS meeting will be in Germany in April 2009 in Garmisch-Partenkirchen. The meeting will be organised by Professor Veit Senner and colleagues. Keep your eye on www.isss2009.com. I will post more detailed information on this website as well as and when it becomes available.