Evaluation of MR Images of the Ankle and Foot in Response to Long-Distance Running: A Systematic Review

Background: It has remained controversial on whether excessive loadings imposed on the ankle and foot complex during long-distance running have a deleterious effect. The aim of this systematic review is to determine whether long-distance running causes any visible changes of the ankle and foot on magnetic resonance imaging (MRI). Methods: Scopus, Web of Science, Embase and Ovid Medline were searched using key terms in relation to MRI findings of the ankle and foot in response to long-distance running, published between 1990 and 2016. The final search was conducted on 19 September, 2016. Studies were identified using inclusion and exclusion criteria. Methodological quality was assessed using a modified Quality Index. Results: The database search initially produced 551 articles and it was screened based on inclusion and exclusion criteria, finally resulting in four articles. Edema was reported in the talus, tibia, calcaneus, navicular, cuboid and cuneiforms. A significant alteration in signal intensity and/or edema was appeared in the calcaneus at the Achilles insertion point, intraosseous and subcutaneous over long-distance running. The diameter of Achilles tendon was also significantly increased. However, when comparing between race finishers and non-finishers, the plantar aponeurosis and subcutaneous were only significantly different, reporting a high rate of edema in non-finishers. Additionally, one study adopted T2* mapping and found significant alteration in T2* values in tibiotalar cartilage, but the value was unexpectedly decreased in the middle of long-distance running. Conclusion: This is the first systematic review to determine the effect of long-distance running on the ankle and foot using MRI. It shows that long-distance running may cause subtle pathological and biochemical changes in the ankle and foot, including the talus, tibia, the distal and proximal group of tarsal bones, 5th metatarsals, soft tissues and the Achilles tendons. However, there is no evidence that these changes have clinical relevance.