Dec. 9, 2005

The most common type of ankle sprain seen in sport involves the ligaments on the lateral (outside) aspect of the ankle. Injury to these ligaments most often occurs with a "rolling" of the ankle inwards, or an inversion mechanism. Inversion mechanisms can involve landing on someone else's foot after jumping or simply stepping on a rock while walking. This type of inversion action to the ankle can damage one or all three of these ligaments in differing degrees.

In the sport of ice hockey the inversion ankle sprain is much less common than in other sports. One type of ankle sprain that has become more prevalent in ice hockey is the "high" ankle sprain, or syndesmotic sprain. The term "high" ankle sprain gets its name from structures that are damaged that are very close to those damaged during an inversion sprain mechanism, but are slightly higher or proximal on the ankle. (Figure 1) Though close in proximity, the structures of the syndesmotic ankle sprain have a greater effect on proper functioning and stability of the ankle and lower extremity. Due to this the syndesmotic sprain will typically take longer to heal and require more time to return to full function than a lateral inversion ankle sprain.

The most common mechanism in ice hockey for the syndesmotic sprain is external rotation of the foot. This can occur in many different ways during play. For example: Sliding into the boards feet first and catching the toe of the skate; tip of the skate catches the ice as the player falls backwards; being down on the ice and receiving a blow to the lateral aspect of the lower leg forcing the heel to the ice; or receiving a blow to the lateral aspect of the knee with the skate planted and externally rotated. It has also been reported that hyperdorsiflexion can cause a syndesmotic sprain when the skate hitting into the boards causes the foot to be forced toward the shin.

Other sports where an external rotation mechanism is common are football and alpine skiing. In football as in hockey, there is commonly an external force placed to the lateral lower leg while the athlete is down on the ground forcing the heel to the ground, or the foot is planted and a force is placed on the lateral aspect of the leg or thigh.

The syndesmotic sprain typically involves damage to one of the ligaments responsible for keeping the articulation of the long bones of the lower leg (the tibia and fibula) together. This ligament, the anterior inferior tibiofibular ligament, along with the distal aspect of the membrane that supports it is located approximately one inch above the most commonly sprained lateral ligament of an inversion ankle sprain, the anterior talofibular ligament. The location of these structures is likely a reason for some of the confusion and frustration that occurred when trying to manage what appeared to be a minimal inversion ankle sprain that was very slow to heal.

Other injuries that can occur with this type of external rotation mechanism are posterior inferior tibiofibular ligament sprains, deltoid ligament sprain, osteochondral fractures of the talus, distal fibular fractures and proximal fibular fracture.

Physical findings after a syndesmotic sprain can appear very similar to those of an inversion ankle sprain. This fact, in conjunction with the proximity of the structures involved in both types of sprains, make the clinical examination one of the most important diagnostic tools. A proper history to find out what direction the foot was forced into is crucial. Point of maximal pain and tenderness is the best clue to determine site of injury. Following a syndesmotic ankle sprain, tenderness over the tibiofibular synesmosis and possibly more proximal along the interosseous membrane between the tibia and fibula is the most tell-tale sign. Tenderness over the medial aspect of the ankle, especially over the deltoid ligament, is also a good sign that something other than an inversion injury has occurred. Swelling can be minimal to moderate over the area. The large egg-shaped edema commonly present after an inversion ankle sprain is not as common after a syndesmotic sprain. With both types of sprains there is a loss of range of motion, pain in extremes of motion and weakness during manual muscle testing. After the clinical exam X-rays, MRI, or CT scans can all be utilized effectively by the physician.

Post injury management of sydesmotic sprains has proven difficult for all sports, hockey included. Pain management and return to normal function becomes important. Management options can include a period of non-weight bearing with the use of crutches with casting or bracing of the ankle, non-steroidal anti-inflammatory regimen, and corticosteroid injection.

After and inversion sprain management of swelling and ecchymosis throughout the ankle presents the greatest challenge. As the swelling begins to subside the athletes pain will usually decrease as range of motion and strength begin to increase. Whereas with the syndesmotic sprain, swelling is usually minimal but the return to full motion and full weight bearing is the challenge.

With a lateral inversion ankle sprain return to competition can sometimes be shortened with the help of bracing or taping. Syndesmotic sprains have proven difficult to support with taping or bracing. Most commonly tape is applied in an attempt to restrict the force responsible for the injury. Additional strips can be applied to compress the distal inferior tibiofibular joint to control its motion.

Syndesmotic ankle sprains in all sports are difficult to manage. The mechanism of injury puts stress on so many structures that are integral to the biomechanical function of the joints of the ankle that normal pain-free function becomes difficult to attain. Return to competition can be very slow and frustrating to every one involved, from athletes and coaches to athletic trainers and physicians. Proper recognition of the injury is the first step in what could be a long road to recovery.

REFERENCES:

1. Doughtie, M. Syndesmotic Ankle Sprains in Football: A Survey of NFL Athletic Trainers. Journal of Athletic Training 1999;34(1):15-18.

2. Norkus, SA, Floyd, RT. The Anatomy and Mechanisms of Syndesmotic Ankle Sprains. Journal of Athletic Training 2001;36(1):68-73.

3. Matava, M. Syndesmosis Sprains in the Hockey Player. Sports Medicine and Hockey: a Summit for the NHL and Beyond. American Orthopaedic Society for Sports Medicine, Toronto Canada, August 24-26, 2001.