Increased ATFL Thickness Associates To Decreased Physical Activity Levels After Acute Lateral Ankle Sprain

Abstract

Lateral ankle sprains remain one of the most common orthopedic injuries. Most concerning are the number of patients that develop long term ankle instability and have decreased activity levels. Despite these problems there are limited long-term studies examining changes after an acute lateral ankle sprain (LAS). PURPOSE: To examine the post-injury thickness of the anterior talofibular ligament (ATFL) and if that thickness relates to physical activity levels one year after an ankle sprain. METHODS: Twenty college students (8 males and 12 females, age=21.2 ± 2.4yr., mass=80.9±21.6kg, ht=173.3±10.6cm) with an acute LAS and 20 healthy matched controls (8 males and 12 females, age=21.9± 2.8yr., mass=79.1±20.2kg, ht=172.5±9.8cm) participated in the study. ATFL thickness was measured with a LOGIQ Book diagnostic ultrasound. The examiner orientated the probe to visualize the cross sectional view of the lateral malleolus, lateral talar articular surface, and the neck of the talus. Once those landmarks and the ATFL were located, images were saved. Thickness of the ATFL was measured at the midpoint of the ligament between the attachments on the lateral malleolus and talus. The main outcome measures were the thickness of the ATFL (mm) at 3 days post LAS and 1 year post LAS, and physical activity levels as measured by the IPAQ and NASA physical activity scales. RESULTS: There was a significant relationship between post-injury ATFL thickness and both the IPAQ and NASA physical activity scales. As ligament thickness increased, “average time spent performing vigorous physical activity” significantly decreased (p=.04, r2=-.86) and “average time spent performing moderate physical activity” (p=.02, r2=-.84) also decreased one year after injury. As ligament thickness increased in subjects with a LAS, time spent walking (p=.01, r2=-.92), days per week where vigorous activity (p=.02, r2=-.81) or moderate activity (p=.04 r2=-.85) was pursued one year after their sprain significantly decreased. CONCLUSIONS: The changes in ATFL morphology may lead to the decreased physical activity levels by contributing to ligamentous laxity and/or perceptions of instability. Future research needs to focus on early interventions to ensure proper ligament healing occurs to restore joint function.