Skiing is one of the more popular winter sports. Skiing requires precise control of the edges of the ski to initiate turns, stop etc – this requires precise movements of pronation and supination of the foot to ‘set the edges’ to cut and glide through the snow.
Injuries in skiers:
Most are traumatic in origin. Those who are at greater risk include those in poor physical condition; the use of poor equipment; poor technique; or ignoring hazardous conditions. Incidence of injury varies from 2.6 to 7.4 injuries per 1000 skier days. Beginners are 3 to 4 times more likely to have an injury. The lower extremity injury is usually the result of torsion whereas the upper extremity is the result of impact. Knee injuries are the most common with the ACL ligament tears being the most common knee injury.
Foot biomechanical abnormalities and skiing technique:
Any lower limb malignment or dysfunction that affects the ability of the foot to adequately ‘set’ the edge of the ski will have an impact on technique.
For example, if the foot is excessively pronated, all of the motion available at the subtalar joint may have been used up to get the foot (and ski) flat on the ground and no more motion is available to further pronate the foot to set the inside edge of the ski for turning, making turning more difficult.
Ski boot-fitting problems:
Different brands of ski boots will fit very differently.
Rigid plastic ski boots hold the ankle slightly dorsiflexed, so that the knee’s are bent and the centre of gravity is slightly forward of the body.
Hallux-abducto valgus, tailor’s bunion, digital deformities grind accommodation into liner
Cuneiform exostosis modify tongue of boot to accommodate
Prominent navicular stretch shell of boot over area; grind liner in area; ‘donut’ padding
Haglund’s deformity grind out liner; accomodative padding
Orthoses in ski boots:
Most retail ski shops will now fit some type of orthoses or comfort device when they sell the boots.
Orthoses need to be shallow and narrow with a low bulk grind so they can be accommodated within the boots. Any additions/modifications to the foot orthoses must have provision for the first ray to adequately exert a medial plantar force to help with setting the ski edge.
Due to the slightly flexed knee stance in skiing which will have a natural pronatory effect on foot, considering casting the foot for orthoses in a slightly pronated position.
In some cases (eg tibial varum), wedges or cants between the boot and ski have been used.
Cross country skiing:
Technique in cross-country skiing is very different to down hill skiing. Chronic overuse injuries are more common in cross-country skiing than downhill skiing – especially anterior compartment syndrome, plantar fascial strain, stress fractures and low back pain.
Injury rates between downhill skiers and snowboarders are generally the same. 15% affect ankle and 1.8% affect foot – of the foot 57% were fractures and 28% were sprains with falling being the most common mechanism of injury. No correlation was found between the types of injury and board used (soft, hybrid or hard). Fractures of the lateral process of the talus are more common in snowboarders (‘snowboarders fracture’) potential for significant morbidity if initial diagnosis is missed (often misdiagnosed as an ankle sprain, due to difficulty of recognising on lateral x-ray) – mechanism is axial loading of the ankle while the foot is inverted and dorsiflexed (may also involve external rotation of leg).