Ultrasound evaluation of extrinsic foot muscles in patients with chronic non-insertional Achilles tendinopathy: A case-control study.

AIM: The purpose of the present study was to compare and quantify with ultrasound imaging (USI) the extensor digitorum longus (EDL), tibialis anterior (TA) and peroneus muscles (PER) muscle thickness and cross-sectional area (CSA) between chronic non-insertional Achilles tendinopathy (AT) and healthy subjects.

METHODS: a sample of 143 individuals was recruited and divided in two groups: chronic non-insertional AT group (n = 71) and a healthy group (n = 72). The thickness and CSA were assessment by USI for EDL, TA and PER muscles in both groups.

RESULTS: The thickness evaluation for the TA muscle increased showing statistically significant differences (P = 0.018) as well as for the thickness of the PER muscles significant differences (P = 0.001) were observed in favor the tendinopathy group. The CSA measurements showed statistically significant differences for a decrease in EDL (P = 0.000), TA (P = 0.001) and PER muscles (P = 0.011) for the tendinopathy group with respect to the control group.

CONCLUSIONS: The CSA of the EDL, TA and PER muscles is reduced in participants with chronic non-insertional AT. The thickness for TA muscle is increased as well as a decrease of PER muscles thickness is presented for the AT group with respect to the control group.