Postural stability deficit could predict ankle sprains: a systematic review

PURPOSE: To perform a systematic review aimed to determine (1) if the postural stability deficit represents a risk factor for ankle sprains; (2) the most effective postural stability evaluation to predict ankle sprains and (3) eventual confounding factors that could influence postural stability and ankle sprain risk. METHODS: A systematic electronic search was performed in MEDLINE, EMBASE and CINAHL using the search terms (balance) OR (postural stability) matched with (lower limb) OR (ankle) OR (foot) and (sprain) OR (injury) on October 2 2017. All prospective studies that evaluated postural stability as risk factor for ankle sprains were included. The PRISMA Checklist guided the reporting and data abstraction. Methodological quality of all included papers was carefully assessed. RESULTS: Fifteen studies were included, evaluating 2860 individuals. Various assessment tools or instruments were used to assess postural stability. The injury incidence ranged from 10 to 34%. Postural stability deficit was recognized as risk factor for ankle sprain (OR = 1.22-10.2) in 9 cases [3 out of 3 with Star Excursion Balance Test (SEBT)]. Among the six studies that measured the center-of-gravity sway, five were able to detect worse postural stability in athletes that sustained an ankle sprain. In nine cases, the measurement of postural stability did not show any statistical relationship with ankle sprains (four out of five with examiner evaluation). In the studies that excluded patients with history of ankle sprain, postural stability was reported to be a significant risk factor in five out of six studies. CONCLUSIONS: The ultimate role of postural stability as risk factor for ankle sprains was not defined, due to the high heterogeneity of results, patient's populations, sports and methods of postural stability evaluation. Regarding assessment instruments, measurement of center-of-gravity sway could detect athletes at risk, however, standardized tools and protocols are needed to confirm this finding. The SEBT could be considered a promising tool that needs further investigation in wider samples. History of ankle sprains is an important confounding factor, since it was itself a source of postural stability impairment and a risk factor for ankle sprains. These information could guide clinicians in developing screening programs and design further prospective cohort studies comparing different evaluation tools. LEVEL OF EVIDENCE: I (systematic review of prospective prognostic studies).