The main aim of this study was to evaluate the capacity of the Ankle-GO score to predict the risk of recurrent LAS two years after the initial injury. First, our results confirmed a high rate of recurrent LAS, with up to 30% of patients reporting a new LAS [15, 29, 30]. The cause of this high rate of recurrence is often explained by poor management of RTS [5] as no evidence-based criteria have been published to date to help make this decision [2, 9]. The goal of the Ankle-GO score is to address this need, and assist clinicians in the decision-making process [10].
The present study showed that the two-month Ankle-GO score effectively predicts the two-year post-LAS risk of recurrence. Scores were significantly lower in patients with reinjury than in those without (Table 3), with a difference between the two groups that was greater than the established minimum detectable change (1.2 points) [10]. In particular patients with a score < 8 points on the Ankle-Go scale had a nearly 9 times greater risk of recurrence during the first two years after LAS.
To the best of our knowledge, this is the first objective RTS criterion to identify individuals with an increased risk of reinjury following LAS. Interestingly, the same cut-off score (8-points) was reported to identify patients who will return to their preinjury level of sports 4 months after LAS, with a sensitivity of 67% and a specificity of 92% [10]. This ability to predict both the level of play after the RTS and the risk of reinjury is due to the multidimensional design of the Ankle-GO. Because the causes of reinjury and the development of CAI are multifactorial [12], the Ankle-GO score was designed to provide a comprehensive assessment, including various components to evaluate all potential deficits associated with LAS and CAI [4, 5, 31]. The selection of items and the rating system for the Ankle-GO score (Table 2) was described in a previous study [10]. In summary, the score includes several items (questionnaires and functional tests) that were chosen based on the PAAS framework [5], clinical guidelines [32, 33] and systematic reviews with expert opinions on RTS [2, 9]. All items were selected based on their relevance, reliability and ability to differentiate CAI patients from copers and healthy individuals [11]. The Ankle-GO is a valid and reliable score [10] including 2 patient-reported outcome measures (FAAM and ALR-RSI), assessing perceived ankle confidence and psychological readiness to RTS [23, 34]. Low scores on these questionnaire are strongly associated with a poor prognosis and greater disability in those with CAI [35, 36]. Functional assessments are highly recommended for the management of LAS patients [4, 32]. Thus, the Ankle-GO score also includes 4 functional tests to evaluate postural control, hopping, jumping and agility, which are frequently impaired following LAS and CAI [2, 5, 9, 37]. Furthermore, and as recommended by Caffrey et al., [21] the feeling of instability reported during the tests was also considered when calculating the Ankle-GO.
When comparing the two-month scores, only the FAAMadl and SEBT scores were significantly lower in patients with a recurrent LAS (Table 4). Because no single component of the Ankle-GO score independently predicted the risk of reinjury, the use of combined scores rather than single evaluations are advisable in CAI patients. It is important to note that the two-month values of all of the Ankle-GO items were below the criteria used to define CAI (FAAMadl scale, ˂90% and FAAMsport scale, ˂80%) [15] in both groups. Similarly, the mean functional test values identified poor balance control during the SLS (> 3 errors) [38] and SEBT (composite score < 89.6%) [39], as well as slow agility test performances (> 12.8s on the SHT and > 17.36s on the F8T) [11, 38] in all patients, whatever their reinjury status. Only posteromedial performance on the SEBT exceeded the cut-off score of (> 91%) [38] in patients with no recurrent LAS, although the difference with the injured group was not significant (93.7 ± 7.9 vs 88.9 ± 9.6 respectively, p = 0.053). This confirms the study by Mcann et al., [8] which showed that the resolution of structural and functional impairment was incomplete, and revealed LAS-related activity limitations at the time of RTS (after an average of 12 days). Although the RTS occurred within a week following LAS in 80% of patients [6, 7], this decision should be based on objective criteria rather than time-related considerations.
Very few prospective studies have evaluated the role of sex in the risk of recurrence in patients with an initial LAS [40]. Results show the risk of reinjury is 4 times higher in women than in men, with no baseline differences in the two-month Ankle-GO score (7.7 vs 8 points, p = 0.8, respectively). Despite conflicting evidence on the influence of sex on LAS [12], women seem to be at a higher risk of LAS [32, 41, 42] and of developing CAI [43] than men. A recent study has also shown that there was a higher risk of recurrence in women following ankle surgery [44]. Because of these differences clinicians should use the Ankle-GO score for both sexes but be more cautious about low scores in women. Unlike previous results, age was not identified as a risk factor for reinjury in our study [12, 45]. Several studies have shown that patients under the age of 24 were at a higher risk of LAS [28, 46]. In the current study, 13 patients (20%) were under 25, and only one had recurrent LAS. Further larger studies targeting adolescents should be performed using the Ankle-GO score to reduce the risk of reinjury.
The socioeconomic costs of poor management of initial LAS can be high because of the high rates of recurrence and CAI [29]. The economic burden of suboptimal care and follow-up after initial LAS has numerous causes including the costs of direct and indirect healthcare and long-term rehabilitation as well as the loss of productivity and quality of life from CAI which diminishes the individual's ability to perform physical activities and potentially leads to a sedentary lifestyles with associated health problems [47, 48]. A long-term analysis of costs after LAS is essential to assess treatment efficacy, and to determine if it is cost-effective and associated with a favorable clinical outcome [29].
The use of the free application Ankle-GO (https://anklego.com/) two months post-LAS can promptly and reliably identify copers and non-copers (i.e., individuals at a high risk of recurrence within two years) and seems to be highly cost-effective [49, 50].
4.1 Strength and Limitations
To our knowledge, this is the first prospective study to evaluate the value of objective RTS criteria to predict the risk of reinjury within two years. However, this study has certain limitations. First, it is well known that the risk of reinjury after LAS is multifactorial [12]. Although age, sport and level of play were included in the predictive model and did not influence recurrence, we did not consider all known risk factors of LAS reinjury. For instance, a previous injury [28] or CAI status at inclusion were not taken into account. Moreover, it has been shown that low-grade LAS results in a higher risk of reinjury [30]. Since the history of ankle sprain, the level of instability and the severity of LAS were not considered at inclusion, these could be important cofounding factors. In addition, reinjury during follow-up was based on a single survey at two years. Thus, the number, severity and exact timing of recurrence were not examined. This study is an important step in establishing objective RTS criteria after LAS for secondary prevention. Further studies using the Ankle-GO score are needed to assess its ability to identify potential copers (secondary prevention), predict the development of CAI (tertiary prevention), as well as the occurrence of a first ankle sprain in a healthy population (primary prevention).
4.2 Clinical Implications
The decision to RTS should not be primarily based on time but on objective criteria. The Ankle-GO score is a cost-effective, rapid (takes less than 20 minutes), and user-friendly tool for clinicians. The Ankle GO score includes various components that target critical outcomes associated with LAS to allow clinicians to identify remaining impairment and reduce the risk of reinjury. During the later stages of rehabilitation and on the RTS continuum, the Ankle-GO score can provide a goal-oriented assessment similar to the clinical assessment of acute lateral ankle sprain injuries [31]. For example, dynamic postural control exercises should be prescribed in patients with a low Ankle-GO score and reduced SEBT values to manage remaining deficits.