www.ski-injury.com
 'Snow fun if you're injured....
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General topics -
Specific Sports -
Specific Injuries - Injury Prevention -
Injury Statistics -
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- Dr Mike Langran |
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On this page.... | Knee injuries |
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| Introduction | Head injuries | ||
| Injury rates | Shoulder injuries | ||
| Alpine ski bindings | Thumb injuries | ||
| Types of injury | Other injuries | ||
Despite the emergence in the 1990's of snowboarding, skiboarding and on-piste telemark skiing, alpine skiing still remains the most popular snow sport by far, accounting for about two thirds of all those on ski slopes. The development of 'carving' or 'shaped' skis in the mid 1990's certainly helped to reaffirm the sport's appeal, allowing beginners to progress rapidly and more advanced skiers to perform tricks and manoeuvres that previously had been the domain of snowboarders. And manufacturers are not resting on their laurels. Expect to see more improvements in ski design, soft boot technology, integrated binding systems and more in the next couple of years! Whilst new developments are always to be welcomed, it often takes quite a few years for sufficient data to emerge before one can judge their effect on snow sports safety - if its even possible at all - so I can't offer an objective opinion on most of these pieces of kit.....but some of them do seem very cool! Interestingly though, some products that have definitely been shown to have a protective effect against injury (such as the Lange RRS boot system which was designed to protect against anterior cruciate ligament [ACL] injury) have been withdrawn as they weren't a commercial success. Possibly a bit ahead of their time, I feel sure that rear release technology will appear again and hopefully save a few ACLs in the process. Protecting the ACL remains the number one priority for many ski safety developers. Thankfully, I am pleased to report that a new binding that offers the first real hope of a reduction in ACL injury risk from the commonest mechanism of injury will be available for the 2008/9 season - lets hope they make a real impact!
This page contains an overview of the main points relating to alpine skiing and injuries - as you will see there are several offshoots from this subject with dedicated pages of their own. If you need any more information then please feel free to send me an email.
Injury
Rates
Current injury
rate in Scotland - 1.74 injuries per 1000 skier days (573 MDBI)
Explain what this means
Since ski injury studies were first reported in the 1970's, the overall rate of alpine ski injuries has decreased by about 50%. It now stands at around 2 injuries per thousand skier days - lower than most people think. What's more, this rate is generally pretty consistent which ever ski area you look at, the world over. The decrease in the overall injury rate is directly linked to developments in alpine equipment as well as improvements in ski area management (grooming, slope design, signage, barriers etc). The biggest decrease has been in lower limb fractures, consequent on the introduction of release binding systems and plastic-shelled alpine boots. There has also been a big reduction in the number of lacerations (cuts) that skiers sustain, thought to be due to ski leashes and ski brakes which now prevent a runaway ski shooting off and injuring someone else. The advent and widespread adoption of carving skis also seems to have had a positive influence on the incidence of alpine skiing injuries, possibly by reducing the number of ACL injuries. I explain why this might be the case in the paragraph below the next flag.
Another way of looking at injury risk to calculate the mean days between injury (MDBI) - this is the total number of skier days in a season divided by the number of injuries seen (Explain this to me a bit more). The higher the value, the less likely an injury is to occur. In Scotland currently, there are 573 MDBI for all alpine ski injuries. This means that on average an individual skier is only likely to injure some area of the body every 573 days they spend skiing. An upper limb injury occurs about once every 1478 days, compared to a lower limb injury once every 809 days - so you can see that the risk of an lower limb injury is about twice that of a upper limb injury on skis - the reverse of the pattern seen amongst snowboarders.
Rates of shoulder, thumb and head injuries have remained static since the 1970's. This is despite the growing number of skiers wearing helmets. Perhaps its too soon yet to see a major change. More on all these injuries later.
The rate of serious knee sprains (in particular anterior cruciate ligament sprains) initially jumped by some 240% (from the 1970's to the early 1990's), then remained static for about ten seasons with an ACL injury incidence rate in MDBI of about 2200. Since about 2000, the ACL injury rate began to decline. The next paragraph explains why this might be so.
It is the view
of the American group that first videoed and described the common mechanisms
behind injury to the ACL that the cause of almost 90% of these injuries is
actually independent of the ski binding worn by the skier at the time. Certainly, despite some
rather ambitious claims, no commercially available ski binding to date has ever been shown to reduce the risk
of ACL injury. Furthermore, the interesting observation that ACL injuries
are rarely seen in skiboarders (the vast majority of whom use an absolute non-release
binding system) adds further credence to the belief that release of the
binding is not related in isolation to ACL injury risk. The Vermont group have argued for
some time now that the tail of the ski is the culprit - acting as a "Phantom
Foot" (much more on this later!) to exert a force across the ACL.
Again, the fact that ACLs don't seem to be a problem on skiboards goes along
with this - because of the short length of a skiboard, there is not much of
a ski tail there behind the boot
to act as a lever on the ACL as there is on an alpine ski. It now seems that
the wide-scale popularity of carving skis (which are
shorter overall and hence have a shorter tail too) may be leading to a
reduction in phantom foot forces across the ACL, hence the lower rates of
ACL injury seen since about the year 2000. This downwards trend in ACL
injury risk is something that will continue to be monitored for a few year
yet.
Nevertheless, there is a new ski binding that has been developed that offers
real hope of ACL protection. It works in a different way to all other bindings
and provides the first glimmer of hope. It works by providing a lateral release mechanism
at the ski boot heel and by so doing reduces the risk of damage to the ACL by
the so-called "Phantom Foot" mechanism of injury - thought to be responsible
for up to 70% of all ACL injuries. More below and also on my
knee page.
Click on the thumbnail to the left to see the five commonest areas for injury amongst
alpine skiers in Scotland, 1999-2005.
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Now, a little bit
about alpine ski bindings - equipment that is generally both taken for granted
and completely misunderstood by most skiers. If you think about it, a ski
binding has a pretty difficult job to do - not only does it have to hold you
in the ski when you want it to but it also has to recognise the exact moment
when you need it to release you. This job is made harder by the fact that the
forces applied to a binding in the course of an average ski run (during which
you may alternatively ski hard for a time and then ski more sedately) vary
enormously - and yet the binding is expected to recognise that moment when the
forces are too strong. Not only that, but the direction of the force applied
varies considerably too as the ski moves and tilts through the turns.
Traditionally, bindings have released either laterally (to the side) or
vertically (heel and toe) - i.e. they have three modes of release. Designing a binding that can protect the anterior
cruciate ligament against injury has been the goal of binding engineers for
many years now. To help you to understand the
concept, I need to get a bit technical so bear with me. When a traditional ski
binding releases laterally at the toe, the boot pivots around an axis located
near the heel of the boot. The position of this pivot as well as the binding
release characteristics determine the combination and direction of forces
required to release the boot from the binding. With the pivot point so far
back, traditional bindings are better at sensing the loads applied at the
front of the ski compared to those at the back of the ski. Hence they release
in a typical forward twisting fall (which protects the medial collateral
ligament from injury) but they do not release in a backwards fall (which is
what happens in the so called Phantom Foot mechanism- the commonest mechanism
of ACL injury, accounting for up to 70% of all ACL injuries. I describe this
mechanism in detail on my knee page) |
Click on the thumbnail above to see a comparison between all the snow sports and the type of injury seen (data from Scotland 1999-2005). Most ski injuries are ligament sprains. Soft tissue bruising and joint injuries are the next most common injuries. Skiers have half the rate of fractures (broken bones) that skiboarders do - about 17% compared to 34%. Joint injuries can be subdivided into dislocations (when the joint surfaces are completely torn apart) and subluxations (when the joint surfaces are moved out of position, but not completely). Very simplistic, but the easiest way to visualise the difference between them is that a dislocation means the joint structures are pulled apart completely whereas in a subluxation things get stretched.
Dislocations
occur when the forces applied across the joint are so great that all the
supporting muscles and other soft tissue structures are torn and the bones
of the joint are no longer in alignment. This usually affects the shoulder
joint or thumb/fingers. A joint subluxation (which usually involves the AC
joint between the collar bone and shoulder blade - see below) occurs when
the forces are less but the supporting tissues are stretched nevertheless
and the joint is pulled out of shape but to a lesser degree.
So now lets look specifically at each area....
Injuries to the knee are the bread and butter of ski patrollers and ski physicians. You'll find much more information on knee injuries on my dedicated page on this website. Injuries tend to follow identifiable patterns and an experienced doctor or patroller will often know the diagnosis after a few questions and a quick look. Damage to the medial collateral ligament (MCL) is the commonest single ski injury of all. This occurs when the lower leg twists outwards relative to the thigh and the MCL takes the strain. Thankfully, most MCL injuries have a good chance of full recovery, as many occur at low speed on beginner slopes. Injury to the anterior cruciate ligament (ACL) is a far more serious situation, and can lead to the end of a skier's career if not diagnosed and treated adequately. Injuries to the lateral collateral ligament, tibial plateau and meniscus (cartilage) are all possible. The important thing is first to differentiate a serious injury from a more minor one, but in all cases appropriate therapy must be started as soon as possible to increase the chances of a successful recovery.
Another development
in the last five years was the rear release boot system introduced by Lange.
The original RRS V9 boot was based on the Vermont studies of the Phantom Foot mechanism of ACL injury.
The idea being that the stiff high back on modern plastic ski boots is
implicated in ACL injuries - so this boot had a mechanism that released the
rear of the boot when excess force was applied here (such as when a skier
falls off balance to the rear). Despite this promising development having
received positive reports at the 2001, 2003 and 2005 ISSS Congresses it did not
attract the commercial
sales that its innovative design deserved and for now has been removed from
sale. I hope we see similar developments on the market in the future. The big
news in knee injuries and alpine skiing is the imminent release of a new
binding to protect the ACL - see my knee page for more details.
As already mentioned, because of their frequency and importance, this site has a whole page
devoted to knee injuries....click
here.
Head injuries can vary from a minor bump on the head with no residual symptoms to major life-threatening trauma, depending largely on the speed of impact, any objects involved in the impact and the area of the head injured. Its a fact that most ski-related deaths involve head injury, usually after a high speed collision with another object such as a tree, rock, pylon or other slope user. Fortunately, most are less serious cases of mild concussion, but even these can leave unpleasant residual symptoms including nausea, light-headedness, poor concentration and headaches. Most head injuries should be at least assessed by a doctor. In those cases where there may have been loss of consciousness, or other symptoms have developed, these people should be sent to hospital for further assessment and observation. The threshold for this should be even lower in children.
In Scotland,
most head injuries are the result of collisions with the lift
apparatus, most noticeably a swinging T-bar. As the turn wheel is very
close to the departure point of the T-bar (see photo
on the left), the T bar
will tend to swing round and hit someone on the head. As a result, fairly consistently,
these injuries account for about 8-10% of all injuries seen. When departing a
T-bar in Scotland, don't just drop the bar on the floor, when it may
recoil violently and hit someone (including you!) on the head.
Instead, hold onto the bar and allow it to recoil into the holder
gently and safely. Compare this to a T-bar from Europe where the T-bar
is channelled safely towards a turn wheel some distance away from the
skier's departure point (photo below right).JPG)
Many head and facial injuries
involve lacerations, usually as the result of collisions with snow
fences, rocks or someone else's ski/snowboard. Fortunately most are
minor and can be patched up fairly easily.
The debate about the benefits of helmets still rages on! Some argue that their use should be made mandatory. There is a lot of
data to absorb but to summarise, its generally accepted now that
currently available helmets will offer protection against the vast
majority of less serious head injuries - such as lacerations,
abrasions and minor contusions. There remains no evidence however to
suggest that wearing a helmet will protect you should you slam into a
stationary object at average skiing speeds - so they don't make you
invincible! You'll find all the
facts and the latest information on my webpage specifically devoted to
the issue of helmets. Click here
to access it.
There are four main shoulder injuries seen in alpine skiers:- dislocated shoulders, fractured clavicles, AC (Acromio-clavicular) joint subluxations and a fractured humerus. Click on any of the thumbnails in the text below to see a full-size picture of the relevant injury.
Shoulder dislocations
These
usually occur as the result of a fall onto an outstretched hand with a twist
of the shoulder into external rotation. The
diagnosis is largely clinical - once you've seen a few they're pretty easy
to spot. The patient is usually supporting the
affected arm and is in great pain. On examination, the normal rounded
contour of the shoulder is lost and palpation reveals that the humeral
head is not sitting where it should be. Reduction to put the joint back in
place should be attempted as soon as possible (but always in a controlled
environment, not out on the hill by a "have a go" hero!!) and gives
instant relief - both to patient and doctor; its a really satisfying
manoeuvre to relieve someone's distress. At our clinic in Aviemore, we are able to reduce about
90% of all shoulder dislocations
and, although other methods exist, we use
Kocher's technique
as it seems to work for us and our patients.
After successful reduction, the shoulder is immobilised in a sling, analgesia given and
mobilisation under the care of a physio can begin fairly rapidly.
The risk of a re-occurrence of the condition is about 85%, as the
supporting tissues will never be as strong as they were. Its much easier
to relocate a joint that keeps dislocating - some patients learn to do it
themselves (but not quite in the Mel Gibson style!) In cases where the
shoulder does keep popping out, stabilising surgery can be performed.
There is now good evidence that primary surgery at or near the time of
dislocation leads to better outcomes - especially amongst younger sporty
patients.
Clavicle (collar bone) fractures
Fractures of the clavicle are frequently the result of the impact radiating up the arm to the collar bone. Most can be diagnosed clinically by finding a tender bump along the line of the bone and x-rays are often unnecessary. Treatment involves resting the arm in a sling or collar and cuff and adequate analgesia, followed by shoulder exercises to keep the elbow and shoulder joint mobile within the limits of one's pain. The support can usually be discarded after 2 weeks or so, depending on the level of pain. If the broken bone is putting pressure on the skin, then surgery may be contemplated but as a general rule, these injuries heal up well without functional loss.
AC joint
injuries
The acromioclavicular joint sits between the outside end of the clavicle and the bit of the shoulder blade known as the acromion. A ligament connects the two and holds the joint together. A fall with direct impact on the outside of the upper arm may lead to this ligament being damaged and tearing, allowing the joint to distort (a so-called subluxation, also known in the game as a "sprung" AC joint). As with all ligament sprains it can be graded 1 to 3 depending on the degree of damage - see the photo for an example of a grade 3 sprain and note the obvious difference in contour between the two shoulders. Sometimes it can be difficult to distinguish an ACJ sprain from a fracture of the very end of the clavicle. Careful (and gentle!) palpation though will usually reveal that the tenderness of an ACJ sprain is very localised to the joint whereas with a broken collar bone it is more spread out. See the photo above left for a classic case of a third degree ACJ sprain - note the prominent deformity at the joint.
Fractured humerus
Finally, a fractured humerus (upper arm bone) can also result from (usually) a direct blow but sometimes a fall onto the outstretched hand. Palpation will reveal tenderness along the line of the bone (best done gently on the inside aspect of the arm where there is less fat and muscle to get in the way). These breaks can be across the shaft of the bone or off the head of the bone at the actual shoulder joint. X-rays are needed here although treatment usually is conservative with a sling and analgesia. Surgery is very rarely needed. The worst case scenario here is someone thinking the arm is dislocated when it is not and pulling on an arm that is actually broken - ouch! I now have a specific page on shoulder injuries - here.
Skier's thumb is
a term coined for an injury affecting the ulnar collateral ligament (UCL) at the metacarpophalangeal joint of the thumb. Its an important injury that is
often mis-diagnosed, under-treated and its functional importance not
appreciated by both doctors and patients - at least initially. Talk to
someone who now has to suffer the long term consequences of a poorly
treated injury and they'll tell you how debilitating it can be. Your
wouldn't believe how important your thumb is for grip strength until you
injure it!
The mechanism of injury is fairly simple. When a skier falls with a pole
in their hand, there is a danger that the handle of the pole will act as a
fulcrum applying force across the joint and thereby putting the ligament
under strain. Depending on the force applied, the ligament may tear
completely (grade 3) or partially (grades 1 & 2). Tenderness is localised
to the joint area, especially when stress is applied across it by the
examining doctor in order to assess the stability of the ligament.
Paradoxically, if the ligament has completely torn, its often not very
painful (as there's no injured ligament remnant left to stretch) but the
joint can be opened up markedly - compare with the other thumb if need be.
If you injure your thumb in this manner skiing, my advice is don't be
fobbed off with a bland "oh, its just a sprain". The thumb joint is the
most important joint in the hand!
X-rays should be taken in most cases to
excluded an associated fracture. Grade 3 injuries should be surgically
repaired within 2 weeks. Grade 1 & 2 injuries may need support with a
splint or a plaster for 6-8 weeks, analgesia and subsequent
physiotherapy.
Injury prevention involves not skiing with the pole straps on so that in
the event of a fall the pole will fall from the hand and not injure the
thumb joint. OK, so the pole may slide down the hill a wee bit but at
least you'll be left with a hand that can still pick it up! This advice
doesn't hold when skiing in deep powder on piste when the loss of a pole could be
very important.
Various devices have been designed to try and help involving the pole
clipping directly into the glove. Others involved "grip poles"
(strapless poles with a device that wraps around the hand and retains
the pole). However, studies showed no difference in the rate of thumb
injuries with these devices and one study even showed that these devices
were associated with a higher rate of thumb injuries (Primiano GA.
Skiers's thumb injuries associated with flared ski pole handles. Am. J.
Sports Med. 1985; 13: 425-427). Thumb injuries seem to have become
somewhat forgotten in recent times as attention is firmly directed at
reducing knee injuries amongst alpine skiers. No question though that a
grade 2-3 UCL injury is more disabling than a grade 1-2 MCL injury of
the knee.
As with the
other snow sports, virtually any part of the body can be injured skiing. We still see
so-called "boot top" fractures of the tibia and fibula at the top of the
ankle where either the
binding fails to release as it should, or the skier unexpectedly enters
softer snow and the skis slow down but his momentum carries him forwards
leading to the injury.
Spinal injuries are thankfully fairly rare but can occur after an
avalanche, when a jump goes wrong or an awkward landing occurs. Important
signs are pain over the spine and/or loss of feeling or function in a
limb. There should always be a high index of suspicion after any high
velocity accident and movement should be kept to an absolute minimum
unless life is in imminent danger. The ski patrol should called as soon as
possible. For more
information on spinal injuries click
here.
If there's an injury I haven't covered that you'd like to know more about,
please feel free to contact me.
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© Copyright Dr Mike Langran 1999-2008 This website is registered and protected under International Copyright Law. All international rights reserved. No part of this web page may be reproduced in any form, or by any electronic, mechanical or other means, without permission in writing from Dr Langran.
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