Overview

The ankle joint is made of three large bones: The lateral, medial, and the posterior malleoli. These are the outer bone of the ankle, the inner bone of the ankle and the bone at the back of the tibia, respectively. Trimalleolar fractures occur when there is a fracture of these three bones.¹ It is a rare type of fracture and accounts for about 7% of all ankle fractures.² However, it is a very severe fracture which requires anatomical surgical reduction and a stable internal fixation.³

Although the ankle is one of the most commonly injured joints during lower limb trauma, it is rare for all three large bones to be fractured at the same time.⁴ When such a fracture occurs, it causes significant trauma and can be life-threatening. 

Trimalleolar fractures may occur due to motor vehicle accidents, sports injuries, or severe falls. Aside from these causes of trimalleolar fractures, it is important to know the risk factors as they play a major role in preventing and managing these fractures.

This article will discuss the risk factors for developing trimalleolar fractures.

Risk factors for developing trimalleolar fractures

Age

Generally, older people are at more risk of suffering from trimalleolar fractures as the bones get weaker with age and they tend to fall more easily.^1,5 However, younger adults who participate in sports are at risk too.

Older people are also more likely to suffer from osteoporosis, a medical condition which causes the bones to become brittle, increasing the risks of different fractures, including trimalleolar fractures.⁶ 

Weight

Another risk factor for developing trimalleolar fractures is weight.⁷ People who are overweight or obese are more at risk of developing ankle fractures compared to others.^8,9 Excess body weight adds pressure on the bones and ligaments of the lower limbs which may increase the risk of fractures.⁸

Sport activity

People who engage in demanding physical activity like sports are more at risk of developing trimalleolar fractures.¹⁰ This is because such physical activities as soccer or basketball that involve rapid movements, jumping, and collisions can easily lead to ankle fractures. 

Gender

While both men and women are at risk of suffering from trimalleolar fractures, females have a higher incidence rate.¹¹ Women, especially elderly women, are more at risk of developing trimalleolar fractures.1 Osteoporosis, which is common in elderly women, may also play a role.¹¹

Meanwhile, men are more likely to engage in sports and high-risk activities, which increases their risk of fractures.

Trauma

Physical trauma, such as trauma due to high-energy impacts as seen in road traffic accidents and falls from significant heights are risk factor for trimalleolar fractures.⁴ Due to the severe nature of these situations, injury to all three ankle bones can occur.

Road traffic accidents are a common cause of trimalleolar fractures due to impact forces. The impact force on the ankle joint during accidents can be quite overwhelming, causing these bones to break. 

The impact force seen in road traffic accidents is also similar to falls from significant heights. 

Previous ankle injury

People who have suffered previous ankle injury or fracture are more at risk than those who haven’t. Previous ankle injuries like sprains, ligament tears, that were not properly treated or did not heal properly, are likely to predispose one to trimalleolar fractures.¹

For instance, people who suffer from chronic ankle instability, a condition which is due to repeated ankle injuries, are prone to trimalleolar fractures.¹²  

Conclusion

Trimalleolar fractures are very severe and can significantly lower your quality of life. Treatment usually requires surgery and physical therapy, and recovering from trimalleolar fractures is a long-term process that usually takes months. Also, people suffering from trimalleolar fractures are unable to walk around easily, as this may further damage the tendons and ligaments of the ankle.

Due to the severity and life-threatening nature of trimalleolar fractures, it is best to know the risk factors and take preventive measures to avoid them. While risk factors like age and gender cannot be modified, factors like weight can be modified. In summary, understanding the risk factors associated with trimalleolar fractures is crucial in preventing them.