Dynamic postural control but not mechanical stability differs among those with and without chronic ankle instability.

Area of Science:

• Biomechanics
• Sports Medicine
• Orthopedics

Background:

• Chronic ankle instability (CAI) is a common sequela of acute ankle sprains.
• Understanding the interplay between dynamic postural control and mechanical ankle stability is crucial for managing CAI.
• Previous ankle injuries can lead to altered sensorimotor function and joint mechanics.

Purpose of the Study:

• To compare dynamic postural control and mechanical ankle stability in individuals with and without CAI, and healthy controls.
• To investigate potential compensatory mechanisms in individuals with a history of ankle injury.

Main Methods:

• Seventy-two participants were divided into three groups: uninjured controls, individuals with previous ankle injury without CAI, and individuals with CAI.
• Dynamic postural stability was assessed using a single-leg hop-stabilization task.
• Mechanical ankle stability was evaluated via the anterior drawer test for ankle joint stiffness and lateral ankle radiography for fibula position.

Main Results:

• Individuals with previous ankle injuries but without CAI demonstrated superior frontal plane dynamic postural stability compared to controls and the CAI group.
• Both CAI and non-CAI injured groups exhibited significantly higher sagittal plane dynamic postural stability and increased ankle joint stiffness than controls.
• Mechanical stability alterations, such as changes in fibula position, are associated with initial ankle trauma.

Conclusions:

• Enhanced frontal plane dynamic postural control may serve as a compensatory strategy to prevent recurrent ankle sprains and the development of CAI.
• Increased ankle joint stiffness and altered dynamic postural control are characteristic of both CAI and individuals with a history of ankle injury.
• Mechanical instability likely originates from the initial traumatic ankle event.