Volume 54: Issue 6

The International Ankle Consortium (IAC), formed in 2004, is an international community of researchers and clinicians who seek to promote and improve the progression and dissemination of information related to conditions affecting the ankle complex, particularly lateral ankle sprains (LASs) and chronic ankle instability (CAI), among physically active populations. We are a collegial network that strives to support the ongoing growth of scientific and clinical evidence to elucidate the mechanisms and characteristics of ankle injuries in an effort to optimize interventions and improve the lives of affected patients.

The primary venue by which the IAC disseminates the work of its

Lateral ankle sprains (LASs) are among the most common injuries incurred during participation in sport and physical activity, and it is estimated that up to 40% of individuals who experience a first-time LAS will develop chronic ankle instability (CAI). Chronic ankle instability is characterized by a patient's being more than 12 months removed from the initial LAS and exhibiting a propensity for recurrent ankle sprains, frequent episodes or perceptions of the ankle giving way, and persistent symptoms such as pain, swelling, limited motion, weakness, and diminished self-reported function. We present an updated model of CAI that aims to synthesize the current understanding of its causes and serves as a framework for the clinical assessment and rehabilitation of patients with LASs or CAI. Our goal was to describe how primary injury to the lateral ankle ligaments from an acute LAS may lead to a collection of interrelated pathomechanical, sensory-perceptual, and motor-behavioral impairments that influence a patient's clinical outcome. With an underpinning of the biopsychosocial model, the concepts of self-organization and perception-action cycles derived from dynamic systems theory and a patient-specific neurosignature, stemming from the Melzack neuromatrix of pain theory, are used to describe these interrelationships.

Copious research exists regarding ankle instability, yet lateral ankle sprains (LASs) persist in being among the most common recurrent musculoskeletal injuries. Key anatomical structures of the ankle include a triform articulating structure that includes the inferior tibiofibular, talocrural, and subtalar joints. Functionally, force absorption and propulsion through the ankle complex are necessary for any task that occurs in weight bearing. For optimal ankle performance and avoidance of injury, an intricate balance between stability and mobility is necessary to ensure that appropriate force transfer occurs during sports and activities of daily living. Consideration for the many structures that may be directly or indirectly involved in LASs will likely translate into advancements in clinical care. In this clinical review, we present the structure, function, and relevant pathologic states of the ankle complex to stimulate a better understanding of the prevention, evaluation, and treatment of LASs.

Objective

To provide a focused overview of the existing literature on the epidemiology of acute ankle sprains (lateral, medial, and high/syndesmotic) with an emphasis on incidence studies from the United States. In addition, we provide a brief overview of chronic ankle instability (CAI), posttraumatic osteoarthritis, and injury prevention to contribute to our understanding of the epidemiology of these injuries and the current state of the science on ankle sprains and ankle instability in sports medicine.

Background

Acute ankle sprains are one of the most common musculoskeletal injuries, with a high incidence among physically active individuals. Additionally, acute ankle sprains have a high recurrence rate, which is associated with the development of CAI. Understanding the epidemiology of these injuries is important for improving patients' musculoskeletal health and reducing the burden of lower limb musculoskeletal conditions.

Description

Acute ankle-sprain incidence rates are summarized among the general population, as well as among physically active populations, including organized athletics and military personnel, with a focus on incidence in the United States. The link between a prior ankle sprain and a future acute ankle sprain is described. We also discuss the association between the incident ankle sprain and adverse, long-term outcomes such as CAI and posttraumatic osteoarthritis. Finally, we summarize injury-prevention successes and future directions for research and prevention.

Clinical Applications

This information is useful for health care providers to understand the expected incidence rates of acute ankle sprains, be aware of the association between ankle sprains and negative short- and long-term outcomes, and be familiar with existing injury-prevention programs.

Driving After Concussion: Clinical Measures Associated with Post-concussion

Kumiko Hashida,

Julia Drattell,

Kim Love,

Robert C. Lynall,

Russell K. Gore,

Hannes Devos, and

Julianne D. Schmidt