Abstract
Lateroplantar foot pain may be caused by various entities, whereby painful os peroneum syndrome should be included in the differential diagnosis. Physical examination and multimodal imaging enable a definitive diagnosis. We report on a 59-year-old man with severe, load-dependent pain, corresponding to an os peroneum syndrome, triggered by a pes planovalgus with consecutively induced focal inflammation and tendovaginitis of the tendon of the peroneus longus muscle. Multifactorial conservative measures including infiltration and shockwave therapy finally led to a restoration of the original condition.