KNEE INJURY DIAGNOSIS

suggest the diagnosis in the majority of cases.

The direction in which the lower leg moves in the fall will dictate which structure(s) is/are involved and the skier’s velocity will influence the severity of the injury sustained.

Beginner and low-intermediate skiers are initially taught to adopt the so-called ‘snowplough’ position. This places partic- ular stress on the medial collateral liga- ment and requires quadriceps strength in order to turn and maintain stability, par- ticularly when a wider stance is adopted. With increasing ability, skiers are able to keep both legs parallel which improves the efficiency of turning and allows for higher speeds to be achieved. In turn, this can lead to more severe injuries being sustained in the event of an accident.

INJURIES ● Rest, ice, compression and eleva- tion ● Wool + crepe compression ban- dage (‘Robert-Jones’) applied for first 24 hours – then replaced by zimmer extension splint ● Less severe injuries may require lesser degrees of support eg. elasti- cated bandage only ● Crutches if required ● Non-steroidal anti-inflammatory drugs unless contra-indicated ● Guidance on regular quadriceps exercises ● Physiotherapy assessment and treatment as soon as possible ● Assessment of ligament stability once acute pain has settled, using the uninjured side for comparison if necessary

GENERAL TREATMENT FOR ALL ACUTE KNEE

Figure 1: Valgus force often occurring in the snowplough position

Differential diagnosis 1. MEDIAL COLLATERAL LIGAMENT SPRAINS Incidence: The most commonly occurring alpine ski injury, accounting for 20-25% of all injuries. It most frequently affects beginner and low-intermediate skiers Cause: Affected individuals are usually in the snowplough position with the knee joint in a valgus position (see Fig.1). Injury results from excessive valgus force being applied to the knee joint, either as

Assessment: In the acute phase, pain usually precludes accurate assessment of ligament stability. When possible, this should be performed by applying valgus stress with the knee in 30º of flexion and the tibia externally rotated (see Fig.1 on p8) Investigation: Often not needed, but radiographs will identify associated bony injuries whilst MRI will detect other soft tissue damage eg. to the ACL/meniscus Treatment: Grade one and two sprains should be placed in an extension splint until pain and swelling subside. Grade three tears may require surgical repair or the application of a plaster cylinder Prevention: Pre-season quads condition- ing, correct binding maintenance and release settings. Avoiding wide snow- plough stances which are inherently unstable. Beginners are advised to allow a fall to occur rather than attempting to resist which in turn may lead to more damage

2. ANTERIOR CRUCIATE LIGAMENT INJURIES Incidence: Accounts for 10-15% of all ski injuries. Often diagnosed late if at all Cause: Intensive American research has

the result of a fall, the skis crossing, or the snowplough stance widening. In more proficient skiers it usually occurs as a result of unexpectedly ‘catching an edge’ Presentation/diagnosis: The diagnosis is usually suggested by the description of the fall. Examination reveals tenderness over the medial collateral ligament and pain on weight bearing. The presence of a haemarthrosis suggests a third degree tear, associated damage to the ACL and/or injury to the bony structures of the knee

identified two main mechanisms that pre- dispose to ACL damage in alpine skiers. These have been termed the “phantom- foot” and “boot-induced” scenarios. The first mechanism occurs when the tail of the downhill ski (the “phantom foot”), in combination with the stiff back of a ski boot, acts as a lever to apply a unique combination of twisting and bending forces across the knee joint. Video analy- sis of more than 14,000 skiing injuries has identified a typical profile that charac- terises this mechanism of injury

PROFILE ● Uphill arm back ● Skier off balance to the rear ● Hips below the knees ● Uphill ski un-weighted ● Weight on the inside edge of downhill ski tail ● Upper body facing downhill ski

THE PHANTOM FOOT

Figure 2: The phantom foot profile that is likely to result in ACL injury

When all six elements of the phantom foot profile are present, injury to the ACL of the downhill leg is extremely likely.

Situations that can predispose to this sce- nario developing are: ● Attempting to get up whilst still mov- ing after a fall ● Attempting a recovery from an off-bal- ance position ● Attempting to sit down after losing control

The boot induced mechanism occurs when a skier becomes off balance to the rear while attempting a jump. Instinctively, the skiers leg fully extend. As a result the skier lands on the tails of the ski which force the back of the ski boot against the

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