Talocrural and subtalar joint instability after lateral ankle sprain

Purpose: Recurrence of lateral ankle sprain (LAS) is common among recreatio nal and competitive athletes. Talocrural (TC) joint laxity has traditionall y been seen as the cause of mechanical instability after LAS. The purpose o f this study was to examine the use of stress fluoroscopy and physical exam ination in the assessment of TC and subtalar (ST) instability in subjects w ith and without a history of LAS. Methods: Twelve subjects with a history o f unilateral LAS and eight healthy controls were examined by two blinded ex aminers. The first examiner performed physical examination on each ankle by using the anterior drawer (AD), talar tilt (TTPE), and medial subtalar gli de (MSTG) tests. Laxity in each ankle was assessed on a 4-point scale. The second examiner performed stress fluoroscopy taking AP views with and witho ut a manually applied supination stress to assess TC laxity and a sidelying modified Broden view with and without stress to assess ST laxity. Subjecti ve examination of the images was used Co determine excessive TC and ST laxi ty. Results: Seventy-five percent of previously injured subjects demonstrat ed unilateral laxity differences of the TC joint using stress fluoroscopy. Of the nine with excessive talar tilt on fluoroscopy, 78% demonstrated exce ssive laxity with the AD and MSTG tests, and 67% demonstrated laxity with t he TTPE test. Sixty-seven percent of those with TC laxity also demonstrated either excessive unilateral or bilateral laxity of the ST joint under stre ss fluoroscopy. Conclusions: These data suggest the existence of a subpopul ation of patients with a history of LAS who demonstrate a pattern of combin ed TC and ST laxity.