Relationships between self-reported ankle function and modulation of Hoffmann reflex in patients with chronic ankle instability

Soleus arthrogenic muscle inhibition following acute lateral ankle sprain correlates with symptoms and ankle disability but not with postural control

BACKGROUND

Acute lateral ankle sprains (ALAS) are associated with long-term impairments and instability tied to altered neural excitability. Arthrogenic muscle inhibition (AMI) has been observed in this population; however, relationships with injury-related impairments are unclear, potentially due to the resting, prone position in which AMI is typically measured. Assessing AMI during bipedal stance may provide a better understanding of this relationship.

METHODS

AMI was assessed in 38 young adults (19 ALAS within 72 h of injury: 10 males, 21.4 ± 2.7 years; 19 healthy controls: 10 males, 21.9 ± 2.2 years; mean ± SD) using the Hoffmann reflex (H-reflex) during bipedal stance. Electrical stimulation was administered to identify the maximal H-reflex (Hmax) and maximal motor response (Mmax) from the soleus, fibularis longus, and tibialis anterior muscles. The primary outcome measure was the Hmax/Mmax ratio. Secondary outcomes included acute symptoms (pain and swelling), postural control during bipedal stance, and self-reported function.

RESULTS

No significant group-by-limb interactions were observed for any muscle. However, a significant group main effect was observed in the soleus muscle (F(1,35) = 6.82, p = 0.013), indicating significantly lower Hmax/Mmax ratios following ALAS (0.38 ± 0.20) compared to healthy controls (0.53 ± 0.16). Furthermore, lower Hmax/Mmax ratios in the soleus significantly correlated with acute symptoms and self-reported function but not with postural control.

CONCLUSION

This study supports previous evidence of AMI in patients with ALAS, providing insight into neurophysiologic impacts of musculoskeletal injury. Our results suggest that assessing AMI in a standing position following acute injury may provide valuable insight into how AMI develops and guide potential therapeutic options to curb and offset the formation of joint instability.

Validation of Foot and Ankle Ability Measure (FAAM) and the Foot and Ankle Outcome Score (FAOS) in individuals with chronic ankle instability: a cross-sectional observational study

Background

Ankle sprain is the most common lower limb injury in physically active individuals. Loss of function, decreased postural control (PC), strength deficit, and reduced range of motion (ROM) are common after acute lateral ankle sprains. Some patients experienced long lasting symptoms, with recurrent sprains, and episodes of giving-way: a condition known as chronic ankle instability (CAI). Evaluating the function in patients with CAI in the clinical environment is important to identify the severity of the condition, in addition to allowing to assess the effectiveness of a given treatment. The aim of this study was to investigate the validation of the Foot and Ankle Ability Measure (FAAM) and the Foot and Ankle Outcome Score (FAOS) in terms of muscle strength, PC and ROM in adults with CAI.

Methods

This is a cross-sectional study. Individuals with CAI aged between 18 and 45 years were eligible. Individuals with CAI were identified using the Identification of Functional Ankle Instability (IdFAI). All patients filled in the FAAM and FAOS scores. Muscle strength was assessed by manual dynamometry, ROM by the Lunge test, PC by computerized posturography, modified Star Excursion Balance Test (mSEBT) and modified Balance Error Score System (mBESS).

Results

50 participants were enrolled in the present study. The mean age of the patients was 27.2 ± 6.3 years, and the mean body mass index was 26.4 ± 4.8 kg/m2. 58% (29 of 50) were men and 42% (21 of 50) women. 18 individuals had unilateral (36%) and 32 bilateral (64%) CAI. The results of FAAM were associated with MCT, mSEBT, invertor muscles strength, plantar flexor muscles strength, dorsiflexor muscles strength, and external hip rotator muscles strength (P < 0.05). The results of FAOS were associated with mSEBT, invertor muscles strength, plantar flexor muscles strength, dorsiflexor muscles strength, evertor muscles strength, and external hip rotator muscles strength, and mBEES (P < 0.05).

Conclusion

Both the FAAM and FAOS demonstrated validity to evaluate postural control and muscle strength in patients with CAI, while no association was found in relation to ankle dorsiflexion.

Ankle Stability and Movement Coordination Impairments: Lateral Ankle Ligament Sprains Revision 2021

This revised clinical practice guideline (CPG) addresses the distinct but related lower extremity impairments of those with a first-time lateral ankle sprain (LAS) and those with chronic ankle instability (CAI). Depending on many factors, impairments may continue following injury. While most individuals experience resolution of symptoms, complaints of instability may continue and are defined as CAI. The aims of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. J Orthop Sports Phys Ther 2021;51(4):CPG1-CPG80. doi:10.2519/jospt.2021.0302.

Stair descent biomechanics reflect perceived instability in people with unilateral ankle sprain history

BACKGROUND

Efforts have been exerted to establish the correlation between objective variables and subjectively perceived ankle instability. Whether or not biomechanical parameters during stair descent can serve as potential assessment tools for perceived stability in people with unilateral ankle sprain history is unknown.

METHODS

Twenty-four subjects with unilateral ankle sprain history were categorized into four groups according to the severity of perceived stability during stair descent. Kinematic and kinetic parameters during stair descent were obtained with a motion analysis system. Spearman's correlation coefficient (ρ) was utilized to test the correlation between the score of perceived stability during stair descent and biomechanical variables.

FINDINGS

Subjects with increased perceived instability were likely to show increased ankle inversion (ρ = -0.46, p = .025) and increased ankle plantarflexion (ρ = 0.46, p = .025), with increased hip adduction (ρ = -0.43, p = .036), hip flexion (ρ = -0.56, p = .004), knee adduction (ρ = 0.45, p = .027), and knee flexion (ρ = -0.44, p = .031). No significant correlation was detected between kinetic variables and perceived stability.

INTERPRETATION

Sagittal and coronal plane motions of the ankle might require rehabilitative intervention to produce improved self-reported outcomes. Kinematic assessment during stair descent can aid in the quantification of subjective ankle instability.

Changes in Spinal and Corticospinal Excitability in Patients with Chronic Ankle Instability: A Systematic Review with Meta-Analysis

The objective of this systematic review with meta-analysis was to determine alterations in spinal and corticospinal excitability of ankle muscles in patients with chronic ankle instability (CAI) compared to uninjured controls. Independent researchers performed comprehensive literature searches of electronic databases and included studies that compared groups with and without CAI and investigated neural excitability with Hoffmann reflex (H-reflex) and/or transcranial magnetic stimulation (TMS). A fixed-effect meta-analysis was conducted to determine group differences for (1) soleus and fibularis maximal H-reflex (Hmax)/maximal M-wave (Mmax)-ratios, and (2) soleus and fibularis longus cortical motor thresholds (CMTs). Seventeen studies were included in the current meta-analysis. They showed that the Hmax/Mmax-ratios of the soleus and the fibularis longus in the CAI group were significantly lower than those in the uninjured control group (soleus: d = −0.41, p < 0.001; fibularis longus: d = −0.27, p = 0.04). There was no evidence for changes in the CMT. This systematic review is the first to demonstrate evidence that patients with CAI present decreased spinal reflex excitability in the soleus and fibularis longus. However, there is no evidence of changes in supraspinal excitability when considering only the CMT. The latter result needs to be interpreted with caution as all except one study demonstrate some changes at the supraspinal level with CAI.

Design and validation of a smart wearable device to prevent recurrent ankle sprain

Lateral ankle sprain is one of the most common ankle injuries, especially in sports. When not treated properly, chronic ankle instability (CAI) may develop causing recurrent sprains and permanent damage to ankle ligaments. In this study, the design, implementation and validation of a smart wearable device connected to a smartphone application is described. This device can predict and prevent the occurrence of ankle sprain. Prediction of potentially harmful motion is achieved by continuous monitoring of ankle kinematics using inertial motion sensors. Detection of such a motion immediately triggers electrical stimulation of the peroneal muscles causing foot dorsiflexion, and hence prevents potential injury. The proposed device has the advantage of having a very short response time of eight milliseconds which is sufficient to halt the sprain motion. Laboratory validation testing using a custom designed trapdoor showed an accuracy of 96% in detecting and correcting hazardous motion. Furthermore, this device complies well with the design constrains of a wearable device such as small size and low power consumption. It is also low cost and unobtrusive due to the wireless connection between all components. Future work is recommended to test the clinical effectiveness of the proposed device in patients with CAI.

Potential Corticomotor Plasticity in Those with and without Chronic Ankle Instability

INTRODUCTION

Quantifying corticomotor alterations is important to understand the neurophysiological mechanisms that likely contribute to the neuromuscular control deficits observed in patients with chronic ankle instability (CAI). Corticomotor output mapping provides further insight into the changes within the motor cortex and identifies potential changes in the area of the motor cortex associated with selected muscles. Therefore, this investigation compared the corticomotor map output for the fibularis longus (FL) muscle in patients with and without CAI.

METHODS

Eighteen CAI patients and 16 healthy controls (HC) volunteered. Transcranial magnetic stimulation was used to map the motor cortex's representation of the FL. The normalized average of three motor evoked potentials at 100% of active motor threshold intensity was recorded for each scalp site on a 6 × 6 cm grid. Corticomotor output map was compared between groups through 1) the size of the corticomotor map area, 2) the volume of the corticomotor map, and 3) the location of cortical representation. Independent t-tests were used to assess group differences in each mapping outcome variable. Cohen's d effect sizes along with 95% confidence intervals were calculated using the pooled SD values.

RESULTS

CAI patients exhibited less map volume (P = 0.018, CAI = 8.2 ± 3.2 cm mV vs HC = 11.3 ± 3.9 cm mV) and map area (P = 0.046, CAI = 12.8 ± 6.0 cm vs HC: 17.4 ± 6.9 cm) compared with HC.

CONCLUSIONS

The smaller map area and volume suggest a more concentrated area of neurons communicating with the FL muscle in patients with CAI. Consequently, motor cortical cells on the border of the FL excitation area are less committed to the proper function of the FL muscle and may be recruited by other surrounding areas. This may explain altered movement strategies that lead to ankle reinjury.

Increased Visual Use in Chronic Ankle Instability: A Meta-analysis

PURPOSE

The underlying cause of balance impairments in chronic ankle instability (CAI) patients remains unknown, but an altered use of sensory information has been hypothesized as a potential cause. The purpose of this systematic review with meta-analysis was to determine whether CAI patients use somatosensory information to the same extent as uninjured controls during static single limb stance.

METHODS

We searched PubMed, CINAHL, SPORTDiscus, and Scopus databases from origin to March 2016 using the combination of key words, including postural control, postural stability, single limb stance, single leg stance, single leg balance, single limb balance, and time to boundary (TTB). Eligible studies had to include instrumented single leg stance with both eyes open and eyes closed in healthy, CAI, or both groups as well as report TTB mean and SD values.

RESULTS

A total of 11 articles were identified. Effect sizes using eyes closed to eyes open standardized mean differences and 95% confidence intervals were calculated for all studies that were included in this investigation. Similarly, pooled estimates for each TTB outcome were compared between the CAI and the uninjured control groups. The mean (95% confidence interval) of the mediolateral TTB (control: -1.50 [-1.71 to -1.29]; CAI: -2.04 [-2.31 to -1.77]), anterioposterior mean (control: -2.19 [-2.43 to -1.96]; CAI: -2.82 [-3.13 to -2.52]), and anterioposterior SD (control: -1.81 [-2.03 to -1.58]; CAI: -2.50 [-2.79 to -2.22]) did not overlap, indicating significant differences between two groups.

CONCLUSION

On the basis of our systematic review with meta-analysis, it appears that CAI patients do not use somatosensory information to the same extent as uninjured controls and instead upregulate the use of visual information during single limb stance.

Therapeutic interventions for improving self-reported function in patients with chronic ankle instability: a systematic review

OBJECTIVE

To identify which therapeutic intervention may be most effective for improving self-reported function in patients with chronic ankle instability (CAI).

DESIGN

Systematic literature review. Articles were appraised using the Downs and Black Checklist by 3 reviewers.

DATA SOURCES

PubMed along with CINAHL, MEDLINE and SPORTDiscus within EBSCOhost for pertinent articles from their inception through August 2016.

ELIGIBILITY CRITERIA FOR SELECTED STUDIES

Articles included were required to (1) be written in English, (2) report adequate data to calculate effect sizes, (3) identify patients with CAI, (4) use some form of therapeutic intervention and (5) use a self-reported questionnaire as a main outcome measurement.

RESULTS

A broad spectrum of therapeutic interventions were identified related to balance training, multimodal rehabilitation, joint mobilisation, resistive training, soft-tissue mobilisation, passive calf stretching and orthotics. All of the articles included in the balance training category had moderate-to-strong Hedges g with none of the 95% CIs crossing 0. Hedges g effect sizes ranged from -0.67 to -2.31 and -0.51 to -1.43 for activities of daily living and physical activity, respectively. The multimodal rehabilitation category also produced moderate-to-strong Hedges g effect sizes but with large CIs crossing 0. Hedges g effect sizes ranged from -0.47 to -9.29 and -0.62 to -24.29 for activities of daily living and physical activity, respectively.

CONCLUSIONS

The main findings from this systematic review were balance training provided the most consistent improvements in self-reported function for patients with CAI.