Jump landing among chronic ankle instability individuals who did or did not attend rehabilitation at the time of injury

Absorption function loss due to the history of previous ankle sprain explored by unsupervised machine learning

BACKGROUND

Ankle sprains are common and cause persistent ankle function reduction. To biomechanically evaluate the ankle function after ankle sprains, the ground reaction force (GRF) measurement during the single-legged landing had been used. However, previous studies focused on discrete features of vertical GRF (vGRF), which largely ignored vGRF waveform features that could better identify the ankle function.

PURPOSE

To identify how the history of ankle sprain affect the vGRF waveform during the single-legged landing with unsupervised machine learning considering the time-series information of vGRF.

METHODS

Eighty-seven currently healthy basketball athletes (12 athletes without ankle sprain, 49 athletes with bilateral, and 26 athletes with unilateral ankle sprain more than 6 months before the test day) performed single-legged landings from a 20 centimeters (cm) high box onto the force platform. Totally 518 trials vGRF data were collected from 87 athletes of 174 ankles, including 259 ankle sprain trials (from previous sprain ankles) and 259 non-ankle sprain trials (from without sprain ankles). The first 100 milliseconds (ms) vGRF waveforms after landing were extracted. Principal component analysis (PCA) was applied to the vGRF data, selecting 8 principal components (PCs) representing 96% of the information. Based on these 8 PCs, k-means method (k = 3) clustered the 518 trials into three clusters. Chi-square test assessed significant differences (p < 0.01) in the distribution of ankle sprain and non-ankle sprain trials among clusters.

FINDINGS

The ankle sprain trials accounted for a significantly larger percentage (63.9%) in Cluster 3, which exhibited rapidly increased impulse vGRF waveforms with larger peaks in a short time.

SIGNIFICANCE

PCA and k-means method for vGRF waveforms during single-legged landing identified that the history of previous ankle sprains caused a loss of ankle absorption ability lasting at least 6 months from an ankle sprain.

The Influence of Therapeutic Exercise after Ankle Sprain on the Incidence of Subsequent Knee, Hip, and Lumbar Spine Injury

PURPOSE

This study aimed to investigate the burden of knee, hip, and lumbar spine disorders occurring in the year after an ankle sprain and the influence therapeutic exercise (TE) has on this burden.

METHODS

A total of 33,361 individuals diagnosed with ankle sprain in the Military Health System between 2010 and 2011 were followed for 1 yr. The prevalence of knee, hip, and lumbar care-seeking injuries sustained after sprain was identified. Relationships between demographic groups, ankle sprain type, and use of TE with rate of proximal injuries were evaluated using Cox proportional hazard models to determine hazard rate effect modification by attribute. The observed effect of TE for ankle sprain on rate of injury to proximal joints was evaluated using Kaplan-Meier survival analyses.

RESULTS

Of the total cohort, 20.5% ( n = 6848) of patients sustained a proximal injury. Specifically, 10.1% of the cohort sustained a knee ( n = 3356), 2.9% a hip ( n = 973), and 10.3% a lumbar injury ( n = 3452). Less than half of the cohort received TE after initial sprain. Patients that did were less likely to have subsequent knee (HR = 0.87, 95% confidence interval [CI] = 0.80-0.94), hip (HR = 0.68, 95% CI = 0.58-0.79), or lumbar (HR = 0.82, 95% CI = 0.76-0.89) injuries.

CONCLUSIONS

One in five individuals that sought care for an ankle sprain experienced a proximal joint injury in the following year. TE for the management of the initial ankle sprain reduced the likelihood of proximal injury diagnosis and should be considered in treatment plans for return to work and sport protocols after ankle sprains.