Relationships between mechanical joint stability and somatosensory function in individuals with chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability (CAI) have demonstrated alterations in ankle mechanics and deficits in sensory function. However, relationships between mechanical stability and somatosensory function have not been examined, nor have those between somatosensory function and injury history characteristics. Therefore, the objective of this study was to examine relationships between (1) somatosensory function and mechanical stability and (2) somatosensory function and injury history characteristics. METHODS: Forty adults with CAI volunteered to participate. In a single testing session, participants completed mechanical and sensory assessments in a counterbalanced order. Dependent variables included anterior/posterior displacement (mm), inversion/eversion rotation (°), SWM index values, JPS absolute error (°), number of previous ankle sprains, and number of "giving way" episodes in the previous 3 months. Spearman's Rho correlations examined the relationships between somatosensory function and (1) mechanical stability and (2) injury history characteristics (p<0.05). RESULTS: No significant correlations were identified between any variables (p>0.11), and all r-values were considered weak. CONCLUSIONS: These results revealed somatosensory function was not significantly correlated to mechanical stability or injury history characteristics. This indicates peripheral sensory impairments associated with CAI are likely caused by factors other than mechanical stability and injury history characteristics.

Contributing factors to star excursion balance test performance in individuals with chronic ankle instability.

The purpose of this study was to determine the contributions of strength, dorsiflexion range of motion (DFROM), plantar cutaneous sensation (PCS), and static postural control to Star Excursion Balance Test (SEBT) performance in individuals with chronic ankle instability (CAI). Forty individuals with CAI completed isometric strength, weight-bearing DFROM, PCS, static and dynamic balance assessments. Three separate backward multiple linear regression models were calculated to determine how strength, DFROM, PCS, and static postural control contributed to each reach direction of the SEBT. Explanatory variables included dorsiflexion, inversion, and eversion strength, DFROM, PCS, and time-to-boundary mean minima (TTBMM) and standard deviation (TTBSD) in the medial-lateral (ML) and anterior-posterior (AP) directions. Criterion variables included SEBT-anterior, posteromedial, and posterolateral directions. The strength of each model was determined by the R2-value and Cohen's f2 effect size. Regression models with an effect size ≥0.15 were considered clinically relevant. All three SEBT directions produced clinically relevant regression models. DFROM and PCS accounted for 16% of the variance in SEBT-anterior reach (f2=0.19, p=0.04). Eversion strength and TTBMM-ML accounted for 28% of the variance in SEBT-posteromedial reach (f2=0.39, p<0.01). Eversion strength and TTBSD-ML accounted for 14% of the variance in SEBT-posterolateral reach (f2=0.16, p=0.06). DFROM and PCS explained a clinically relevant proportion of the variance associated with SEBT-anterior reach. Eversion strength and TTB ML explained a clinically relevant proportion of the variance in SEBT-posteromedial and posterolateral reach distances. Therefore, rehabilitation strategies should emphasize DFROM, PCS, eversion strength, and static balance to enhance dynamic postural control in patients with CAI.

Clinical and laboratory measures associated with health-related quality of life in individuals with chronic ankle instability.

OBJECTIVE: To identify clinician and laboratory-oriented measures of function capable of explaining health-related quality of life in individuals with chronic ankle instability. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: Forty physically active individuals with chronic ankle instability attended a single testing session. MAIN OUTCOME MEASURES: Participants completed health-related quality of life, postural control, strength, sensory, and mechanical assessments. Health-related quality of life assessments included the Short Form-12 Physical and Mental Summary Components, Disablement in the Physically Active Scale, Fear-Avoidance Beliefs Questionnaire, and the Foot and Ankle Ability Measure. RESULTS: A combination of mechanical and functional impairments accounted for 18-35% of the variance associated with health-related quality of life related to physical function and fear. Although physical impairments accounted for 7% of the variance associated with mental health-related quality of life, the overall model was associated with a weak effect size. CONCLUSION: Measures of postural control, dorsiflexion range of motion, plantar cutaneous sensation, and ankle arthrometry contributed to a significant proportion of the variance associated with health-related quality of life in those with chronic ankle instability. Other variables should be examined to address mental components of health-related quality of life.

The effectiveness of foot orthotics in improving postural control in individuals with chronic ankle instability: a critically appraised topic.

CLINICAL SCENARIO: Chronic ankle instability (CAI) is a condition commonly experienced by physically active individuals. It has been suggested that foot orthotics may increase a CAI patient's postural control. CLINICAL QUESTION: For patients with CAI, is there evidence to suggest that an orthotic intervention will help improve postural control? SUMMARY OF KEY FINDINGS: The literature was searched for studies of level 2 evidence or higher that investigated the effects of foot orthotics on postural control in patients with CAI. The search of the literature produced 5 possible studies for inclusion; 2 studies met the inclusion criteria and were included. One randomized controlled trial and 1 outcomes study were included. Foot orthotics appear to be effective at improving postural control in patients with CAI. CLINICAL BOTTOM LINE: There is moderate evidence to support the use of foot orthotics in the treatment of CAI to help improve postural control. STRENGTH OF RECOMMENDATION: There is grade B evidence that foot orthotics help improve postural control in people with CAI. The Centre of Evidence Based Medicine recommends a grade of B for level 2 evidence with consistent findings.