Prevalence, impact and long-term consequences of lateral ankle sprains

Musculoskeletal injuries are a leading cause of physical limitations in active individuals. One of the most common of these injuries is the lateral ankle sprain (LAS)—an injury that occurs when the ankle suddenly twists or rolls outward, stretching or tearing the ligaments on the outer side of the joint. LAS is not limited to athletes; it frequently affects the general population and represents a major healthcare burden worldwide.

While many patients recover quickly from an ankle sprain, research shows that nearly half of those injured never seek medical treatment, and a large portion develop recurrent sprains or chronic instability. This chronic condition, known as chronic ankle instability (CAI), results in a persistent feeling of the ankle “giving way,” along with pain, weakness, and impaired balance. Over time, these deficits can restrict activity levels and lead to post-traumatic osteoarthritis (PTOA)—a degenerative joint condition that may require surgery, often emerging at a younger age than other forms of arthritis.

The long-term consequences of ankle sprains extend beyond the individual, contributing to high medical costs and reduced productivity. The International Ankle Consortium emphasizes the importance of prevention, early intervention, and evidence-based management to reduce these outcomes and promote long-term joint health.

Understanding Lateral Ankle Sprains (LAS)

A lateral ankle sprain is an acute injury to the ligaments on the outside of the ankle, typically occurring when the foot rolls inward or downward suddenly. This excessive inversion causes damage to structures such as the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL).

Sports like basketball, soccer, and volleyball present the highest risks, as they involve jumping, landing, and sudden changes in direction. Laboratory and video analyses from live sports have shown that most LAS injuries result from the ankle rapidly turning inward with internal rotation—sometimes with, but often without, direct contact from another player. These findings underline that forceful twisting alone can cause significant ligament damage, emphasizing the need for proper conditioning and protective strategies.

Frequency and Epidemiology

Lateral ankle sprains are the most common lower-limb injury among active individuals, accounting for up to 80–90% of all ankle injuries.

• Fong et al. (2007) analyzed data from over 200,000 participants across 70 sports and found that in 34% of sports, the ankle was the most frequently injured area.
• Doherty et al. later confirmed that indoor and court-based sports have the highest incidence—approximately 7 sprains per 1,000 exposures.
• Women and younger athletes are disproportionately affected, possibly due to biomechanical and hormonal factors influencing ligament stability.
• Data from the NCAA Injury Surveillance System identified basketball and soccer as leading causes of ankle ligament injuries, while similar rates are reported in military and general populations.

Globally, ankle sprains account for millions of emergency department visits annually. In the UK, they are among the most common reasons for emergency care in young females, while similar trends are observed in the USA and Netherlands, demonstrating the widespread public health impact of this injury.

Mid-Term and Long-Term Effects: From LAS to CAI

Although many ankle sprains heal without complications, recurrence and long-term deficits are common.

• Within the first year post-injury, patients have twice the risk of reinjury compared to uninjured individuals.
• Recurrent sprains can result in Chronic Ankle Instability (CAI), characterized by ongoing pain, weakness, impaired balance, and repeated “giving way” episodes.

Hertel’s Model describes CAI as the interaction of:

• Mechanical instability – structural laxity caused by ligament damage.
• Functional instability – deficits in proprioception and neuromuscular control.

Delahunt et al. and Hiller et al. refined this model, recognizing CAI as a heterogeneous condition encompassing both subjective instability and measurable functional deficits. The International Ankle Consortium now provides standardized research criteria for CAI diagnosis, ensuring consistent definitions and treatment approaches.

Prevalence of CAI

Studies reveal that up to 70% of individuals with a prior ankle sprain develop some form of CAI. Rates exceed 25% among athletes in sports such as basketball, soccer, volleyball, and handball. In specialized groups, such as ballet dancers, more than half report chronic ankle issues after prior sprains. Even in the general population, over 20% of individuals report ongoing ankle instability or pain following initial injuries.

Link Between LAS, CAI, and Post-Traumatic Osteoarthritis (PTOA)

Long-term consequences of ankle sprains can include post-traumatic osteoarthritis (PTOA), which severely limits mobility and quality of life. Between 70% and 80% of ankle PTOA cases are attributed to prior ligament injuries, especially LAS. Unlike hip or knee osteoarthritis, ankle PTOA often develops decades earlier—sometimes within 20–30 years of the original injury.

Arthroscopic studies confirm early degenerative changes in many CAI patients:

• Hintermann et al. reported cartilage lesions in 55% of CAI cases within two years post-injury.
• Takao et al. found osteochondral lesions in nearly one-third of patients within seven months.
• Taga et al. documented chondral lesions in 95% of young CAI patients, highlighting early degenerative processes even in active populations.

This evidence underscores the importance of comprehensive rehabilitation and monitoring to reduce the long-term risk of ankle arthritis.

Impact on Physical Activity and Quality of Life

Ankle sprains can disrupt both short- and long-term physical activity. Persistent pain, instability, and reduced confidence in movement can lead to decreased participation in exercise and sports, contributing to reduced cardiovascular fitness and higher BMI over time.

Research shows that:

• Many individuals with CAI engage in less physical activity than their uninjured peers.
• Chronic instability leads to decreased proprioception, slower muscle activation, and poorer balance control, especially under fatigue.
• The decline in activity not only affects physical health but can also impact emotional well-being and overall quality of life.

Overly aggressive return-to-play protocols or insufficient rehabilitation exacerbate the problem. Early structured rehabilitation and a gradual return to sport are critical for restoring strength, balance, and neuromuscular control.

Summary and Key Takeaways

• Lateral ankle sprains (LAS) are the most common sports-related injuries worldwide and often lead to chronic ankle instability (CAI) if untreated.
• Recurrent sprains and instability increase the risk of post-traumatic osteoarthritis (PTOA), which can develop early and lead to lifelong disability.
• Proper rehabilitation emphasizing balance, strength, and proprioceptive training is crucial for recovery and prevention of reinjury.
• Both under-treatment (lack of follow-up care) and overly rapid return to play increase the risk of chronic instability.
• Preventive education, early diagnosis, and personalized rehabilitation programs are key to reducing long-term complications and preserving mobility and health.

Research Spotlight

A recent study in the Journal of Experimental Orthopaedics examined how recovery time after a lateral ankle sprain (LAS) depends on injury severity. Using ultrasound to measure talofibular displacement—the small shift between the ankle bones—the researchers followed 101 patients with varying degrees of ligament damage.

They found that mild sprains (Grade I) typically stabilized within about two weeks, while more severe injuries (Grades II and III) required around six weeks for the joint to return to normal alignment. The study underscores that ligament healing and recovery speed vary significantly by severity and that premature return to sport or activity could increase the risk of reinjury and chronic ankle instability.

These findings support tailoring treatment duration and rehabilitation intensity to each patient’s injury grade rather than using a one-size-fits-all timeline. (“Study on how ankle sprain recovery time varies by severity – see PubMed.“)