Chronic Ankle Instability and Hip Muscle Function: a systematic review

Purpose/background The connection between hip strength and knee function is widely accepted in rehabilitation. The beginnings of evidence supporting a connection between the hip and ankle in people with chronic ankle instability (CAI) causes clinicians to question how the hip and the ankle may interact in this population. The purpose of this review is to provide a cohesive summary of the current available evidence examining hip muscle function in people with chronic ankle instability so that clinicians are better able to treat these patients. Methods An electronic search of PubMed was performed to locate studies published in peer-reviewed journals that directly examined hip muscle function in people with chronic ankle instability. Studies published between January 1, 2010 and September 1, 2017 were identified using varying combinations of the keywords “ankle”, “hip”, chronic ankle instability”, and “muscle activity”. Results Nine of 9 included articles suggested that clinicians manage the entire kinetic chain, rather than just the local ankle deficits, in people with chronic ankle instability. Seven of 9 articles directly demonstrated the presence of proximal neuromuscular changes in people with CAI and 6 of 9 articles found differences in hip muscle performance in people with CAI versus healthy controls. Varying study techniques, subject classification styles and outcome measures limit generalizability of results but most studies reported findings consistent with neuromuscular changes effecting both distal and proximal musculature in people with CAI Conclusions Clinicians should include assessment and intervention for proximal muscle function changes when treating patients with chronic ankle instability, as there is evidence that proximal neuromuscular changes effect movement patterns in this population. More research is needed to further elucidate the neuromuscular changes that are found in this population and to determine how clinicians can best manage these deficits to improve function in people with CAI