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| Journal of the New Zealand Medical Association,
11-June-2010, Vol 123 No 1316
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Alistair Patton, Jim Bourne, Jean-Claude Theis
Snowsports in New Zealand have increased in popularity since
1979 with 1.4 million visitors to New Zealand skifields in
2006.1 The most popular sport is still
traditional alpine skiing which has been developing for over a century. Over
this time alternative downhill sports have been invented, most of which have
been short lived. However snowboarding has grown disproportionately and now
accounts for a third of snow sport participants in New
Zealand.1 With increasing popularity there is a
need to understand the pattern of injuries associated with these sports.
Injury rates in skiers have fallen from 5–8 injuries
per 1000 skier days in the 1970s to 2–3 injuries per 1000 skier days
currently2. This has been attributed to the
evolution of equipment design, such as break-away bindings, and improved
planning and grooming of slopes. It has been noted that the pattern of injury
has also changed with lower leg injuries becoming less common while the
incidence of proximal leg and knee injuries are
increasing.3
Snowboarders experience a higher injury rate of 4–16
injuries per 1000 snowboarder days 4, 5 and
this appears to be increasing. The most common injuries in descending order are
head and facial, left upper limb, spine, chest and abdomen, left lower
extremity, right upper extremity, and right lower
extremity.6 This pattern demonstrates
laterality of injury as one-side leads, a technical variance to
skiing7; it also shows that upper body injuries
are more common.8,9
Differences in equipment and body position between the two
sports may lead to different mechanisms and hence patterns of injury. The injury
rate is also influenced by the demographics of participants. In regard to the
lower limb the most obvious difference is the plane of stance to the direction
of travel i.e. skiers travel forward, whereas snowboarders go sideways with one
side leading.
The boots and bindings are also very different. Snowboarders
fix both feet to one board with ‘soft’ boots and non-releasing
bindings. Skiers use ‘hard’ plastic shelled boots with releasing
bindings and a ski on each foot. We aimed to define the differences in the
pattern of lower limb fractures requiring operative management in these
contrasting sports at the Central Otago skifields.
MethodsAll patients who required surgical, orthopaedic
treatment for ski or snowboard-related leg injuries treated by the orthopaedic
department at Dunedin Hospital during the period 2002 to 2008 were included. An
electronic search via the clinical coding of injuries was undertaken to find all
cases of leg fractures that had been admitted. This was then focused to those
that had occurred whilst skiing or snowboarding.
Patient records were manually reviewed to determine the
nature and mechanism of injury. Age, gender and nationality were noted.
Circumstance of injury was grouped as occurring during a jump, fall or
collision. If the specific skifield that the injury occurred at was available
this was also recorded. Laterality of the injury was documented.
Anonymous data retrieval was used to fulfil local
ethical requirements.
ResultsA total of 108 cases (80 skiers and 28 snowboarders)
suffered fractures of the patella and distally, whilst participating in their
chosen sport during the seven year study period. A mean of four cases per year
occurred due to snowboarding and 11.4 cases per year due to skiing.
The demographic characteristics of the 108 cases are
presented in Table 1. The snowboarders had an mean age of 27 years (range 9
to 45 years) and 86% were male. The mean age of the skiers was 32 years (range 4
to 65 years) and 60% were male. In both groups the majority of patients were
resident in New Zealand (15 snowboarders and 51 skiers).
Table 1. Patient
demographics
Each group was analysed to establish the fracture pattern
and circumstances of the injury, as displayed in Tables 2 and 3.
Table 2. Fracture pattern and circumstance
among snowboarders
Table 3. Fracture pattern and circumstance
among skiers
In both sports falls were the most common cause of injury.
However the next most common cause for injury in snowboarders was jump related,
making up 32% of the group. For skiers this only accounted for 7.5% of injuries.
Collision was the cause of injury in 13.8% of cases for skiers but only 3.6% of
snowboarder injuries.
Snowboarders were more likely to injure the ankle (39% of
cases). The next most common point was mid shaft tibial fractures (28%),
followed by distal third (18%), proximal third (11%), and knee (4%). Skiers were
most likely to have a midshaft tibial fracture (44%). Followed by proximal third
(32.5%), ankle (12.5%), distal third (9%), and knee fractures (2.5%). This is
illustrated in Figure 1.
19 of 28 fractures occurred to the left leg in snowboarders
and 9 to the right. In skiers the laterality was evenly distributed, 41 right
and 39 left.
Of 16 tibia and fibula fractures in snowboarders, 5 involved
the tibia alone, and 9 involved both the tibia and fibula, only 2 were isolated
fibula fractures. Of the 70 tibia or fibula fractures in skiers, 36 were of the
tibia alone and 34 involved both the tibia and fibula with no isolated fibula
fractures.
Figure 1. Comparison of fracture site between
skiers and snowboarders
 DiscussionThe demographic data suggests that a male in their late
20’s is the most likely snowboarder to sustain a leg fracture. This is
consistent with previous studies 8, 10.
Today’s Otago skiers have a higher average age and a more even gender
split than snowboarders, also consistent with previous
studies.11 The majority of patients in our
study were from New Zealand but a higher proportion of non New Zealand residents
are snowboarders. This fits with the analysis of the New Zealand ski industry
which shows a static domestic market but an overall increase in overseas users,
particularly snowboarders, in the last 10 years
1.
A large proportion of the injuries to the proximal tibia are
tibial plateau fractures. Of these the higher grade (Schatzker classification
5&6) injuries occur in high speed skiing accidents. Skiers are also more
likely to sustain avulsion fractures of the anterior tibial spine or posterior
intercondylar area, where the anterior and posterior cruciate ligaments,
respectively, insert.13,14 Our finding of a
higher number of proximal third tibia and fibula fractures, including tibial
plateau fractures, in skiers corresponds with the published data.
Fractures of the tibial diaphysis are common long bone
fractures. Often the consequence of road traffic accidents they are also common
in snowsports. Traditionally they have been difficult to manage but advances in
intramedullary nails, pre-contoured plates and locking plates has led to a
decrease in fracture complications and an improved
outcome.15 Both skiers and snowboarders have a
high incidence of these fractures but snowboarders are more likely to fracture
more distally than skiers.
Compared to skiers the snowboarder group had a slightly
higher proportion of fractures that involved the tibia and fibula, 57% versus
47%, which have been associated with high energy or rotational
forces.15 In the case of skiers these large
rotational forces may be due to the ski failing to release from the breakaway
binding and thus acting as a long lever arm, in snowboarders these injuries may
be caused by a higher initial force transmitted through bindings that are not
designed to breakaway. The higher initial force being related to the
preponderance for snowboarders to undertake activities such as jumping.
Isolated fibula fractures were seen exclusively in the
snowboarders and we postulate that the hard shell boots worn by skiers protect
them from these injuries. A study of novice snowboarders using hard ski boots
showed similar findings,16 and we know that
prior to the introduction of modern ski boots and bindings the pattern of injury
was similar to that seen in modern
snowboarders.17
The finding of more left sided injuries in snowboarders
(68%) may be explained by the stance. Most snowboarders lead with their left
foot and when moving at speed this is at 90 degrees to the direction of travel,
with weight distribution biased towards this lead leg. Skiers will transfer
their weight from one leg to the other as they turn, and when moving at speed
the foot and ankle face in the direction of travel with no laterality of weight
distribution. This accounts for the equal distribution of fractures between
sides we observed in skiers.
Conclusion—The pattern of injury in
these two sports is very different. This study has highlighted how vulnerable
the ankle is to injury in snowboarding and we offer reasoning for this based
upon an understanding of the differences in equipment used in skiing and
snowboarding. The challenge to reducing the incidence of ankle injury in
snowboarders is in the balance of allowing movement in order to accomplish the
tricks and jumps deemed integral to the sport whilst protecting the ankle,
although more rigid boots such as those used in skiing may create more proximal
injuries by transmitting force proximally.
We propose a more protective boot for the lead foot of
snowboarders that includes a lace up ankle support. In our opinion and with
personal experience of both sports, no advances in equipment design can negate
the importance of common sense and abiding by local skifield policies when
undertaking these sports.
Limitations—Many injuries that do not
require orthopaedic operative intervention are seen and treated by skifield
doctors and general practitioners within Otago, thus we were unable to obtain
details of these injuries within our unit. Injuries sustained in the Queenstown
skifields that require operative management are usually treated in Invercargill,
and as such the incidence of injuries is higher, but the anatomical distribution
or circumstances of injury should not differ. We elected to exclude injuries of
the femur and above in order to make data retrieval less complicated. Inaccurate
coding may have led to some cases being missed.
Competing interests: None known.
Author information: Alistair Patton
(snowboarder), Final Year Medical Student, Cardiff University, Cardiff, UK; Jim
Bourne (skier) Orthopaedic Registrar, Dunedin Public Hospital, Dunedin, New
Zealand; Jean-Claude Theis, Professor, Orthopaedic Department, Dunedin Hospital,
Dunedin, New Zealand
Acknowledgements: We thank Jo Hill
(Clinical Records and Coding) and Jenny Hanson (Data Management Team) at Dunedin
Hospital.
Correspondence: Jim Bourne, Orthopaedic
Dept, Lancaster Royal Infirmary, Lancaster, Lancashire, UK. Email: drjtbourne@gmail.com
References:
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