A PROSPECTIVE-STUDY OF ANKLE INJURY RISK-FACTORS

Many factors are thought to cause ankle ligament injuries. The purpose of this study was to examine injury risk factors prospectively and de termine if an abnormality in any one or a combination of factors ident ifies an individual, or an ankle, at risk for subsequent inversion ank le injury. We examined 145 college-aged athletes before the athletic s eason and measured generalized joint laxity, anatomic foot and ankle a lignment, ankle ligament stability, and isokinetic strength. These ath letes were monitored throughout the season. Fifteen athletes incurred inversion ankle injuries. Statistical analyses were performed using bo th within-group (uninjured versus injured groups) data and within-subj ect (injured versus uninjured ankles) data. No significant differences were found between the injured (N = 15) and uninjured (N = 130) group s in any of the parameters measured. However, the eversion-to-inversio n strength ratio was significantly greater for the injured group compa red with the uninjured group. Analysis of the within-subject data demo nstrated that plantar flexion strength and the ratio of dorsiflexion t o plantar flexion strength was significantly different for the injured ankle compared with the contralateral uninjured ankle. Individuals wi th a muscle strength imbalance as measured by an elevated eversion-to- inversion ratio exhibited a higher incidence of inversion ankle sprain s. Ankles with greater plantar flexion strength and a smaller dorsifle xion-to-plantar flexion ratio also had a higher incidence of inversion ankle sprains.