Study Design Case-control.

Objective To examine the difference in inversion-eversion (IE) ankle ligament laxity between those with and without previous lower extremity injuries.

Background Individuals with previous ankle sprains have increased ankle ligament laxity. However, with the body as a kinetic chain, mechanical ankle instability could increase injury risk at more proximal joints of the lower extremity.

Methods and Measures 72 Division-I collegiate athletes (40 females, 32 males; age=20.1±1.37 years; height=179.3±12.3 cm; mass=75.2±14.0 kg) that did not suffer an ankle sprain 6 months prior to data collection were recruited for this study. After signing the informed consent, IE ankle ligament laxity was taken using an instrumented ankle arthrometer (Blue Bay Research Inc., Milton, FL). Previous ankle sprains and additional lower extremity injuries were documented from the participants’ medical records. Two one-way ANOVAs analysed the differences in IE measurements between a previously sprained group and a healthy group and between a previous lower extremity injury group and a healthy group.

Results The previously sprained group had a significantly greater IE laxity (n=75 ankles, 36.08^o ± 11.07^o) than the healthy group (n=69 ankles, 31.86^o ± 9.48^o) at p=0.022. However, no differences were found in IE laxity between the previous lower extremity injury group (n=89 ankles, 36.03^o ± 11.48^o) and the healthy group (n=55 ankles, 32.87^o ± 11.48^o) at p=0.101.

Conclusion As expected, those with a history of an ankle sprain presented with an increase of ligament laxity. However, there were no differences in IE laxity between groups with and without lower extremity injuries. Lower extremity injuries documented include knee ligamentous and meniscal injuries, patellar tendonitis, and fractured ankles. With the foot and ankle as the base of the body’s kinetic chain, it does not seem that mechanical ankle instability has an affect on injuries at more proximal joints.