Sonography of the Achilles Tendon After Complete Rupture Repair: What the Radiologist Should Know

This review aims to provide the radiologist with simple and systematic guidelines for evaluation of the Achilles tendon after complete rupture repair. Currently, there is a plethora of nonsurgical and surgical treatments, but sonographic examination has shown no significant differences between them. A systematic analysis of several parameters (morphologic characteristics, structure, color Doppler vascularization, and mobility) should be undertaken. Morphologically, the repaired tendon is larger, wider, or both. The loss of the fibrillary structure, inhomogeneity, and the surgical material in the context of the tendon are "normal" aspects after a repaired rupture. The presence of fluid collections when affecting greater than 50% of the surface of the tendon and extensive calcifications should be considered pathologic aspects. In the immediate postoperative period, there is the absence of vascularization detectable by color Doppler imaging. During the first 3 months, there is an increase in intratendinous vascularization with hypervascularization. From 3 to 6 months, stabilization and regression of the vascularization occur. Beyond the first 6 months, the hypervascularization is pathologic. The pattern of motion is, generally, reduced considerably more often in surgically treated tendons than in non-surgically treated ones. Elastography generally shows a hard appearance, with only a relatively heterogeneous pattern. In conclusion, a treated tendon will never regain a normal sonographic appearance, and the operator must distinguish between normal posttreatment changes and real pathologic characteristics.