Discriminating Between Copers and People With Chronic Ankle Instability

Abstract

Context: Differences in various outcome measures have been identified between people who have sprained their ankles but have no residual symptoms (copers) and people with chronic ankle instability (CAI). However, the diagnostic utility of the reported outcome measures has rarely been determined. Identifying outcome measures capable of predicting who is less likely to develop CAI could improve rehabilitation protocols and increase the efficiency of these measures.Objective: To determine the diagnostic utility and cutoff scores of perceptual, mechanical, and sensorimotor outcome measures between copers and people with CAI by using receiver operating characteristic curves.Design: Case-control study. Setting: Sports medicine research laboratory. Patients or Other Participants: Twenty-four copers (12 men, 12 women; age = 20.8 ± 1.5 years, height = 173 ± 11 cm, mass = 78 ± 27 kg) and 24 people with CAI (12 men, 12 women; age = 21.7 ± 2.8 years, height = 175 ± 13 cm, mass = 71 ± 13 kg) participated.Intervention(s): Self-reported disability questionnaires, radiographic images, and a single-legged hop stabilization test.Main Outcome Measure(s): Perceptual outcomes included scores on the Foot and Ankle Disability Index (FADI), FADI-Sport, and a self-report questionnaire of ankle function. Mechanically, talar position was quantified by measuring the distance from the anterior tibia to the anterior talus in the sagittal plane. Sensorimotor outcomes were the dynamic postural stability index and directional indices, which were calculated during a single-legged hop stabilization task.Results: Perceptual outcomes demonstrated diagnostic accuracy (range, 0.79-0.91), with 95% confidence intervals ranging from 0.65 to 1.00. Sensorimotor outcomes also were able to discriminate between copers and people with CAI but with less accuracy (range, 0.69-0.70), with 95% confidence intervals ranging from 0.37 to 0.86. The mechanical outcome demonstrated poor diagnostic accuracy (0.52).Conclusions: The greatest diagnostic utility scores were achieved by the self-assessed disability questionnaires, which indicated that perceptual outcomes had the greatest ability to accurately predict people who became copers after their initial injuries. However, the diversity of outcome measures that discriminated between copers and people with CAI indicated that the causal mechanism of CAI is probably multifactorial.Key Words: self-report disability, positional fault, dynamic postural control Key Points• Perception-based outcomes had the greatest ability to discriminate between copers and people with chronic ankle instability.• Sensorimotor-based outcomes discriminated between copers and people with chronic ankle instability but with less accuracy than perception-based outcomes.• Mechanical outcomes demonstrated a low level of diagnostic utility.

Selection Criteria for Patients With Chronic Ankle Instability in Controlled Research: A Position Statement of the International Ankle Consortium

“…Many recent reviews and multifactorial studies have provided important information outlining that there are multiple potential contributing mechanical, neuromuscular, functional, and/or perceived deficits that may persist long after physiologic tissue healing times have elapsed and interventions have been completed following an acute ankle joint sprain. [23][24][25][26][27][28][29][30][31][32][33][34] Consistently, these reviews and multifactorial studies support the proposition that CAI is a multifaceted and complex condition, requiring further indepth interdisciplinary study.…”

Time series of ground reaction forces following a single leg drop jump landing in elite youth soccer players consist of four distinct phases

“…On the other hand, despite lower reliability, outcomes of the dynamic phase may still detect impairments, due to higher effect sizes [6]. This is illustrated by the findings of Wikstrom et al, who showed that the mediolateral stability index had higher accuracy to differentiate between 'copers' and individuals with chronic ankle instability than the other stability indices, whilst having a 'poor' reliability [12,34].…”

Selection Criteria for Patients With Chronic Ankle Instability in Controlled Research: A Position Statement of the International Ankle Consortium

“…The healthcare burden associated with ankle instability necessitates increased research and clinical outcomes that can be used to reduce the disability and recurrence rates associated with CAI. It is clear from the body of literature that there are many contributing factors to CAI that can create a host of impairments 15,20,21,24,29,28,39,47 ; however, this condition is more heterogeneous than many realize. 15,23 Therefore, researchers need to be cognizant of criteria that are best associated with CAI based on current available evidence.…”

“…Previous authors have considered mechanical instability as an explanatory factor for lingering ankle instability, but there has not been a definitive association of ankle laxity with CAI. 6,8,15,20,23,24,28,29,47 Hertel's 20 original model differentiated mechanical instability from functional instability. More recently, Hiller et al,23 refining the model of categorizing CAI, suggested as many as 7 subgroups of individuals with CAI that would likely provide better homogeneity in describing the pathology.…”

“…Data from other multifactorial studies that have included measures of mechanical instability in patients with CAI suggest that mechanical instability alone may not be a consistent identifier of this pathology. 28,47 A recent advancement in the CAI literature has been the stratification of individuals, based on structural and functional impairments associated with ankle instability. Multiple studies by Brown et al [6][7][8] compared sensorimotor and biomechanical measures between patients classified as having mechanical ankle instability, functional ankle instability, and no measurable ankle instability or repeated injury (copers).…”