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Differences between mechanically stable and unstable chronic ankle instability subgroups when examined by arthrometer and FAAM-G.

Lohrer H, Nauck T, Gehring D, Wissler S, Braag B, Gollhofer A - J Orthop Surg Res (2015)

Bottom Line: Known group validity and eta(2) were established by comparing manual and arthrometer testing results.In this investigation, the ankle arthrometer demonstrated a high diagnostic validity for the determination of mechanical ankle instability.A clear interaction between mechanical (ankle arthrometer) and functional (FAAM-G) measures could not be demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Institute for Sports Medicine, Otto-Fleck-Schneise 10, D-60528, Frankfurt am Main, Germany. lohrer@smi-frankfurt.de.

ABSTRACT

Background: The objective measurement of the mechanical component and its role in chronic ankle instability is still a matter of scientific debate. We analyzed known group and diagnostic validity of our ankle arthrometer. Additionally, functional aspects of chronic ankle instability were evaluated in relation to anterior talar drawer.

Methods: By manual stress testing, 41 functionally unstable ankles were divided as mechanically stable (n = 15) or mechanically unstable (n = 26). Ankle laxity was quantified using an ankle arthrometer. Stiffness values from the load displacement curves were calculated between 40 and 60 N. Known group validity and eta(2) were established by comparing manual and arthrometer testing results. Diagnostic validity for the ankle arthrometer was determined by a 2 × 2 contingency table. The functional ankle instability severity was quantified by the German version of the Foot and Ankle Ability Measure (FAAM-G). Stiffness (40-60 N) and FAAM-G values were correlated.

Results: Mechanically unstable ankles had lower 40-60 N stiffness values than mechanically stable ankles (p = 0.006 and <0.001). Eta for the relation between manual and arthrometer anterior talar drawer testing was 0.628. With 5.1 N/mm as cut-off value, accuracy, sensitivity, and specificity were 85%, 81%, and 93%, respectively. The correlation between individual 40-60 N arthrometer stiffness values and FAAM-G scores was r = 0.286 and 0.316 (p = 0.07 and 0.04).

Conclusions: In this investigation, the ankle arthrometer demonstrated a high diagnostic validity for the determination of mechanical ankle instability. A clear interaction between mechanical (ankle arthrometer) and functional (FAAM-G) measures could not be demonstrated.

No MeSH data available.


Related in: MedlinePlus

Flow chart to demonstrate the recruitment procedure of the tested groups under mechanical (MAI) and functional (FAI) considerations. CAI = chronic ankle instability. MAI = mechanical ankle instability. FAI = functional ankle instability.
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Fig2: Flow chart to demonstrate the recruitment procedure of the tested groups under mechanical (MAI) and functional (FAI) considerations. CAI = chronic ankle instability. MAI = mechanical ankle instability. FAI = functional ankle instability.

Mentions: By announcement in the local press, 32 males were recruited (Figure 2). We included 26 subjects (Table 1). These “subjects” complained residual symptoms after ankle sprain(s) and were therefore CAI by definition [3]. Compared with these mildly affected CAI subjects, we assumed that patients who were waiting for ankle ligament reconstruction will suffer more severe CAI symptoms [32]. Therefore, 15 consecutive patients were selected in our sports medicine institute to represent a “patients’ group” (Table 1). All these patients were diagnosed with MAI and were already described in a previous paper [32]. All subjects and patients were lower competitive level or recreational athletes (Table 1). Inclusion and exclusion criteria were based on the Ankle Injury History Questionnaire [11]: Subjects and patients were included when they reported at least one of the following criteria: a history of at least one ankle sprain more than 1 year ago. Additionally, actual symptoms of giving way, or feeling of giving way (at least once a month), and/or feelings of instability had to be stated (Table 1). Subjects and patients were separated based on the presence or absence of MAI (Figure 1). Persons with systemic diseases, neuromuscular disorders, and obesity (BMI greater than or equal to 30) were excluded. Subjects who complained of ankle pain as a primary symptom, who had an acute ankle sprain within the past 6 months or had previous foot and ankle surgery, fractures, or anatomic deformities of the lower extremities were also excluded. Persons who presented more than 10 degrees of knee hyperextension in manual testing were also excluded.Figure 2


Differences between mechanically stable and unstable chronic ankle instability subgroups when examined by arthrometer and FAAM-G.

Lohrer H, Nauck T, Gehring D, Wissler S, Braag B, Gollhofer A - J Orthop Surg Res (2015)

Flow chart to demonstrate the recruitment procedure of the tested groups under mechanical (MAI) and functional (FAI) considerations. CAI = chronic ankle instability. MAI = mechanical ankle instability. FAI = functional ankle instability.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4359539&req=5

Fig2: Flow chart to demonstrate the recruitment procedure of the tested groups under mechanical (MAI) and functional (FAI) considerations. CAI = chronic ankle instability. MAI = mechanical ankle instability. FAI = functional ankle instability.
Mentions: By announcement in the local press, 32 males were recruited (Figure 2). We included 26 subjects (Table 1). These “subjects” complained residual symptoms after ankle sprain(s) and were therefore CAI by definition [3]. Compared with these mildly affected CAI subjects, we assumed that patients who were waiting for ankle ligament reconstruction will suffer more severe CAI symptoms [32]. Therefore, 15 consecutive patients were selected in our sports medicine institute to represent a “patients’ group” (Table 1). All these patients were diagnosed with MAI and were already described in a previous paper [32]. All subjects and patients were lower competitive level or recreational athletes (Table 1). Inclusion and exclusion criteria were based on the Ankle Injury History Questionnaire [11]: Subjects and patients were included when they reported at least one of the following criteria: a history of at least one ankle sprain more than 1 year ago. Additionally, actual symptoms of giving way, or feeling of giving way (at least once a month), and/or feelings of instability had to be stated (Table 1). Subjects and patients were separated based on the presence or absence of MAI (Figure 1). Persons with systemic diseases, neuromuscular disorders, and obesity (BMI greater than or equal to 30) were excluded. Subjects who complained of ankle pain as a primary symptom, who had an acute ankle sprain within the past 6 months or had previous foot and ankle surgery, fractures, or anatomic deformities of the lower extremities were also excluded. Persons who presented more than 10 degrees of knee hyperextension in manual testing were also excluded.Figure 2

Bottom Line: Known group validity and eta(2) were established by comparing manual and arthrometer testing results.In this investigation, the ankle arthrometer demonstrated a high diagnostic validity for the determination of mechanical ankle instability.A clear interaction between mechanical (ankle arthrometer) and functional (FAAM-G) measures could not be demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Institute for Sports Medicine, Otto-Fleck-Schneise 10, D-60528, Frankfurt am Main, Germany. lohrer@smi-frankfurt.de.

ABSTRACT

Background: The objective measurement of the mechanical component and its role in chronic ankle instability is still a matter of scientific debate. We analyzed known group and diagnostic validity of our ankle arthrometer. Additionally, functional aspects of chronic ankle instability were evaluated in relation to anterior talar drawer.

Methods: By manual stress testing, 41 functionally unstable ankles were divided as mechanically stable (n = 15) or mechanically unstable (n = 26). Ankle laxity was quantified using an ankle arthrometer. Stiffness values from the load displacement curves were calculated between 40 and 60 N. Known group validity and eta(2) were established by comparing manual and arthrometer testing results. Diagnostic validity for the ankle arthrometer was determined by a 2 × 2 contingency table. The functional ankle instability severity was quantified by the German version of the Foot and Ankle Ability Measure (FAAM-G). Stiffness (40-60 N) and FAAM-G values were correlated.

Results: Mechanically unstable ankles had lower 40-60 N stiffness values than mechanically stable ankles (p = 0.006 and <0.001). Eta for the relation between manual and arthrometer anterior talar drawer testing was 0.628. With 5.1 N/mm as cut-off value, accuracy, sensitivity, and specificity were 85%, 81%, and 93%, respectively. The correlation between individual 40-60 N arthrometer stiffness values and FAAM-G scores was r = 0.286 and 0.316 (p = 0.07 and 0.04).

Conclusions: In this investigation, the ankle arthrometer demonstrated a high diagnostic validity for the determination of mechanical ankle instability. A clear interaction between mechanical (ankle arthrometer) and functional (FAAM-G) measures could not be demonstrated.

No MeSH data available.


Related in: MedlinePlus