Relationship Between Functional Ankle Instability and Postural Control

Fri, 24 Oct 2008 00:00:00 EST

Marcos de Noronha, Kathryn M. Refshauge, Jack Crosbie, Sharon L. Kilbreath
STUDY DESIGN: Controlled laboratory study using a cross-sectional design. OBJECTIVES: To investigate the relationship between postural control and functional ankle instability during a hop-landing task, and to investigate whether postural control is altered in people with functional ankle instability. METHODS AND MEASURES: Sixty volunteers classified by the Cumberland Ankle Instability Tool (CAIT) scores formed the external control group (CAIT score, ≥ 28, n = 31) and the instability group (CAIT score, ≤ 27 and history of at least 1 ankle sprain; n = 29). Postural control was measured with the landing test, in which participants stood on 1 lower extremity for 3 seconds on a step, then hopped down onto a force plate and regained postural stability after landing. The main outcome measurements were time to stability (TTS) after landing for ankle inversion, dorsiflexion, and summated electromyographic (EMG) signal amplitude for the tibialis anterior, soleus, and fibularis longus. The secondary outcomes were the proportion of movement in the frontal plane for hip and ankle, the variability of inversion movement prior to hopping, and the variables from ground reaction force. RESULTS: There were no associations (P > .05) between the CAIT scores and the TTS for ankle inversion (r = -0.25), dorsiflexion (r = -0.04), summated EMG (r = -0.13) and proportion of movement in the frontal plane (r = 0.005). Participants in the instability group took longer to regain stability in inversion and displayed greater inversion variability prejump than the control group (P = .05 and .009, respectively). CONCLUSIONS: Ankle inversion control is affected in people with functional ankle instability in tasks of postural control after landing from a hop.

J Orthop Sports Phys Ther. 2008;38(12):782-789, published online 24 October 2008. doi:10.2519/jospt.2008.2766

KEY WORDS: ankle injuries, ankle sprain, joint instability, postural control

Deficits in Detection of Inversion and Eversion Movements Among Subjects With Recurrent Ankle Sprains

Mon, 05 Feb 2007 09:45:00 EST

Kathryn M. Refshauge, Jacquelene Raymond, Sharon L. Kilbreath
Study Design: Observational cross-sectional design. Objectives: To determine whether a deficit exists in the ability to perceive inversion and eversion movements among subjects with recurrent ankle sprains. Background: Although unproven, ankle sprains are thought to recur because proprioception is impaired subsequent to the original sprain. Proprioception has been widely studied, however, the specific property of movement perception has not been rigorously examined for both inversion and eversion movements. Methods and Measures: The ability to perceive passive inversion and eversion movements imposed at the relaxed ankle was measured in 39 subjects with recurrent ankle sprains (sprainers) and 30 subjects with no history of ankle injury (controls) by an assessor masked to subject group. The 70% detection level for movement perception was determined for 3 velocities, 0.1°/s, 0.5°/s, and 2.5°/s, tested in random order. Results: The 70% detection level for inversion and eversion movements improved with increasing velocity in both groups. At all velocities, the 70% detection level for movements imposed at the ankle of the sprainers was significantly worse than for controls. Conclusions: Perception of passive inversion and eversion movements imposed at the ankle was impaired in subjects with recurrent ankle sprains. The impairment was evident at the 3 velocities tested, 0.1°/s, 0.5°/s, and 2.5°/s.

J Orthop Sports Phys Ther. 2003; 33(4):166-176.

Key Words: kinesthesia, proprioception, sensory function

Journal of Orthopaedic & Sports Physical Therapy - Sharon L. Kilbreath, PT, MClSc, PhD

Relationship Between Functional Ankle Instability and Postural Control

Deficits in Detection of Inversion and Eversion Movements Among Subjects With Recurrent Ankle Sprains