Dysfunction of the Posterior Tibial Tendon: Stages and Ultrasound Findings

Source Limitation

The fragments provided as the sole source of facts contain no information on posterior tibial tendon dysfunction: stages (e.g., Johnson–Strom classification), tendon thickness threshold values, criteria for partial/complete rupture, signs of tenosynovitis and planovalgus deformity. All these data require clarification from specialized materials. [to be clarified]

Applicable General Methodological Principle

The only relevant thesis confirmed by the fragments concerns the anisotropy artifact when examining tendons and other fibrous structures. When the beam does not fall perpendicular to the tendon fiber direction, the tendon falsely appears hypoechoic and may mimic pathology.

To differentiate artifact from true damage, the transducer should be tilted (heel-toe manoeuvre, angulation 5–15°), returning the beam to perpendicular incidence. If the 'finding' disappears with tilting — this is anisotropy, not tendon pathology.

Assessment of Muscle and Fatty Degeneration

According to general data from the fragments, signs of atrophy with fatty replacement of muscle include altered echotexture and increased echogenicity; echogenicity is compared with a reference muscle (e.g., trapezius or deltoid). The source does not contain direct application of specific numerical criteria to the posterior tibial muscle. [to be clarified]