Unusual proximal fragment migration of an os peroneum fracture with associated peroneus longus tendon injury-a tree often hides a forest

Migration of the os peroneum: An enigmatic phenomenon explored through radiological perspectives

The os peroneum is an accessory ossicle located along the lateral aspect of the cuboid bone. Its position can serve as an indicator of peroneus longus tendon (PLT) injury. Imaging studies including radiographs and MRI can help detect malposition of the os peroneum and progressive injuries to the PLT and its associated structures. We report a case of a woman with recurrent foot and ankle pain, demonstrating progressive retraction of the os peroneum, implying severe PLT injury which may have ultimately predisposed her to a traumatic fifth metatarsal base fracture. This case highlights the importance of scrutinizing the appearance and position of the os peroneum on radiographs.

Retracted os peroneum with partial integrity of the peroneus longus tendon

Painful os peroneum syndrome encompasses a spectrum of disorders associated with lateral foot and ankle pain. In the setting of an os peroneum fracture or diastasis of a partitioned os peroneum, marked displacement of the proximal fragment on radiographs is often used as an imaging surrogate for detection of a complete peroneus longus tendon tear. We present a case of a displaced proximal fragment of the os peroneum above the level of the ankle joint on radiographs and MRI associated with incomplete tear of the peroneus longus tendon. We hypothesize that such an injury pattern results from an anatomic prerequisite where the os peroneum occupies a portion of the cross-sectional diameter of the tendon. We suggest that the retracted proximal moiety of the sesamoid bone is the result of elastic recoil of delaminated fibers of the peroneus longus directly inserting on the os, whereas eccentric bundles of the tendon draping over the os remain in continuity. Although treatment implications are debatable, the case questions the assumption of a complete peroneus longus tear based on a retracted os peroneum on radiography and highlights the role of MRI in providing a full description.

Anteroposterior Radiograph of the Ankle with Cross-Sectional Imaging Correlation

The focus of this article is to illustrate various pathologic entities and variants, heralding disease about the ankle, based on scrutiny of AP radiographs of the ankle, with correlative findings on cross-sectional imaging. Many of these entities can only be detected on the AP ankle radiograph and, if not recognized, may lead to delayed diagnosis and persistent morbidity to the patient. However, a vigilant radiologist, equipped with the knowledge of the characteristic appearance and typical locations of the imaging findings, should be able to make the crucial initial diagnosis and surmise additional findings to be confirmed on cross-sectional imaging.