Efeito de um programa de reabilitação global com ênfase local no controle postural estático, estabilidade dinâmica e funcionalidade em indivíduos com instabilidade lateral de tornozelo

Abstract

Background: Lateral ankle instability (LAI) is caused by one or more episodes of ankle sprain, which may be associated with injuries to the tissues that cross this joint. Since it is a condition that affects a large part of the population, bringing costs to the health system, loss of functionality, balance and mobility to the affected individuals, it has been extensively investigated to determine better treatments and assessment tools that allow the identification of a more efficient approach. Although there are several exercise protocols for LAI, most of them follow a joint-segmented rehabilitation model, mainly involving strengthening muscles in isolation (conventional exercises) with a special focus on the evertor muscles. In addition, they involve the use of implements such as elastic bands and balance discs. However, exercises that involve the entire kinetic chain (global exercises), in addition to being multi-joint, allow the training of several components at the same time, such as strength, mobility and balance, and are therefore naturally functional and easily accessible. In addition to documenting changes in functionality and body factors, the effects of treatment approaches for ILT can be assessed by assessing postural control, which has been considered a relevant marker of recovery in individuals affected by ILT. Despite the frequent use of postural control assessment, there are still divergences about which variables would be most appropriate to identify ILT, document the progression of this condition, or distinguish individuals with and without this injury. Since numerous factors contribute to an individual's adequate postural balance in multiple contexts, nonlinear analyses that consider postural control over time may be an alternative because they are more comprehensive. Objectives: (1) To compare the effects of a rehabilitation program using global exercises and a program with conventional exercises on static postural control, dynamic balance, and functionality in individuals with ILT; (2) To investigate whether the protocol will bring changes in dorsiflexion range of motion and passive ankle stiffness; (3) To verify the outcomes six months after the end of rehabilitation, in addition to the recurrence rate of new sprains; (4) To investigate how classical (area, mean velocity and standard deviation of amplitude) and non-linear (sample entropy) assessments of postural control can capture possible changes in postural control between individuals with and without ILT; (5) To investigate whether, after rehabilitation in individuals with ILT, linear variables and sample entropy will be able to track changes in postural control; and (6) To investigate whether the postural control of individuals with ILT assessed by these variables will be different or similar to that of individuals without injury after rehabilitation. Methodology: The study lasted eight weeks, in which individuals with ILT were randomly divided into two groups (conventional rehabilitation and global rehabilitation). Both groups received home exercise booklets every two weeks. Blinded evaluators performed four assessments of postural control, dynamic stability using the Modified Star Excursion Balance Test (SEBTm), level of functionality using the Foot and Ankle Ability Measure (FAAM), dorsiflexion range and passive ankle stiffness using an inclinometer and goniometer, respectively. The recurrence rate was reported at follow-up. Individuals' adherence to the exercises was verified using the Exercise Adherence Rating Scale (EARS-br) and attendance records on a calendar. In addition, individuals without ILT with characteristics similar to those of ILT were recruited for postural control analysis. Postural control analysis was performed using the trajectory of the center of pressure of the force platform by extracting the variables of total mean velocity, area and standard deviation of the displacement amplitude, and by nonlinear analysis of sample entropy. Statistical analysis: Quantitative descriptive data were analyzed using the independent sample t-test and categorical data using the Chi-square test. The outcome variables were analyzed using mixed ANOVA with one independent factor (group) and one repeated measure factor (time). The intention-to-treat analysis was performed. In the case of a significant effect of the time of assessment or interaction, post hoc analyses were performed. An α of 0.05 was used for all analyses. Results: Increase in dynamic stability (p=0.001), mean velocity (p=0.001), standard deviation (p=0.002) and area (p=0.001) of the COP; functionality (p=0.001) and dorsiflexion ROM (p=0.001), which were maintained after 6 months, except for the standard deviation of the COP amplitude in both the group that received global exercises and the group that received conventional exercises. The recurrence rate of sprains was lower in the global rehabilitation group (88.2% without new sprains) compared to the conventional rehabilitation group (52.6%). When comparing the global exercise group with individuals without ILT, greater regularity of the COP was found (p=0.021). After four weeks of treatment, the regularity of the global exercise group decreased (p=0.018) and approached the values of individuals without injury, maintaining itself after eight weeks (p=0.001). In the linear analysis of the COP, only the mean velocity distinguished the groups with and without ILT (p=0.016), with a reduction after four weeks of treatment (p=0.001) and maintained until the eighth week (p=0.001). The COP area reduced over time in the global exercise group (four weeks p=0.012 and eight weeks p=0.034) but the standard deviation of the amplitude showed no differences when compared to individuals without injury. Conclusion: After four weeks of rehabilitation in the global exercise and conventional exercise groups, there were improvements in all outcomes except passive ankle stiffness, with effects amplified after eight weeks and maintained after six months. No superiority of the global exercise group over the conventional exercise group was observed, but the global rehabilitation group achieved the minimum significant difference in functionality in daily activities and a lower rate of recurrence of sprains. Average speed and regularity distinguished the postural control of individuals with and without ILT, being higher in the ILT group. There was an improvement in postural stability demonstrated by the reduction in speed and oscillation area in the ILT group compared to individuals without injury. The analysis of regularity highlighted that rehabilitation in the ILT group expanded the motor repertoire to deal with postural demands, indicating increased adaptability, reaching patterns similar to those without injury.