Progressive retraction of a fractured os peroneum suggesting repetitive injury to the peroneus longus tendon

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.

Split Anterior Tibial Tendon Transfer to Dorsal Lateral Foot for Cavovarus Deformities With Neuropathic Ulcerations: A Case Series

Cavovarus deformity leads to increased peak pressure on the plantar lateral foot, which can lead to ulceration, and can potentially progress to amputation. Techniques have been suggested in the treatment of cavovarus deformity, such as peroneus brevis or longus tendon transfer, anterior tibial tendon lengthening, posterior tibial tendon transfer, or boney resection. This case series shows split anterior tibial tendon transfer as a surgical reconstruction of cavovarus pedal deformity. Our technique of split anterior tibial tendon in-phase transfer to the dorsal lateral foot, restores the eversion and dorsiflexory pull necessary to offset peroneal attenuation. The procedure can be performed primarily or staged, in order to achieve infection temporization prior to the transfer. A total of 14 patients underwent split anterior tibial tendon transfer, 57.14% (8/14) of which had preoperative ulcerations, and 42.86% (6/14) of which had preoperative hyperkeratotic pre-ulcerative lesions. The preoperative ulcerations were present for an average of 67.89 weeks (range 2-232), with an average area of 6.09 ± 7.44 cm². The ulcerations healed in 75% (6/8) of the patients, at 19.67 weeks (range 1.57-76), with new ulceration occurrence in 7.14% (1/14) of patients, 7.14% (1/14) rate of ulceration recurrence. None of the patients went on to minor or major amputation. The goal of the tendon transfer is to decrease midfoot plantar pressures on the lateral foot and allow for resolution of pre-existing ulcerations and rebalancing the foot and ankle.

Lateral Heel Pain Caused by Impingement of Hypertrophic Peroneal Tubercle and Os Peroneum

Hypertrophic peroneal tubercle (HPT) is an overgrowth of the peroneal tubercle located on the lateral aspect of the hindfoot, which could cause tenosynovitis of the peroneus longus tendon. Os peroneum (OP) is an accessory ossicle that exists in the peroneus longus tendon at the lateral aspect of the calcaneocuboid joint. Both HPT and OP can cause lateral foot pain and occasionally require surgical treatment. We encountered a case of lateral foot pain of HPT coexisting with OP. Careful preoperative magnetic resonance imaging, dynamic ultrasonographic image, and block injection suggested an impingement of HPT and OP as a cause of lateral foot pain. Surgical resection of HPT, while retaining OP, successfully achieved pain relief in the patient. To the best of our knowledge, this is the first report presenting a case of HPT coexisting with OP successfully treated without OP resection.

Fracture of an os peroneum

Os peroneum is an accessory ossicle located within the peroneus longus tendon, present in 26% of the population. Fractures of the os peroneum present as pain localized on the lateral aspect of the foot resulting from direct trauma, muscle contraction, inversion injuries or chronic overuse injuries. We document a case of a fractured os peroneum that resulted in the insidious onset of ongoing pain that was managed conservatively.

How to increase the accuracy of the diagnosis of the accessory bone of the foot?

PURPOSE

The study was conducted to search for confident radiological signs in symptomatic cases of accessory bones. A normal accessory bone appearance on X-ray does not exclude that the accessory bone is the source of the discomfort; because of this, MRI examination can later be applied as part of the diagnosis.

METHODS

We retrospectively analysed cases of 64 patients with recognized 70 symptomatic accessory bones of the foot. The average age was 29.2 (range 8-42) years. We included only patients with X-ray and MRI examinations. We investigated the following radiological features of the bone (structural and signal) in relation to soft tissue.

RESULTS

The most constant symptoms identified in our study were bone marrow oedema (93%) and soft tissue oedema (77%). Changes in structures in which accessory bones were located or in adjacent structures to accessory bone were identified: tendon changes 51%, fluid adjacent to bone 51% and tenosynovitis 46%. MRI revealed changes in bone structure that are not seen on X-ray, including changes in contour (28%), sclerosis (3%) or osteonecrosis (3%).

CONCLUSIONS

MRI plays an important role in determining whether accessory bones cause symptoms because it shows specific and accurate changes in accessory bone and/or in adjacent soft tissue.

The peroneus longus muscle and tendon: a review of its anatomy and pathology

This article will review the anatomy and common pathologies affecting the peroneus longus muscle and tendon. The anatomy of the peroneus longus is complex and its long course can result in symptomatology referable to the lower leg, ankle, hindfoot, and plantar foot. Proximally, the peroneus longus muscle lies within the lateral compartment of the lower leg with its distal myotendinous junction arising just above the level of the ankle. The distal peroneus longus tendon has a long course and makes two sharp turns at the lateral ankle and hindfoot before inserting at the medial plantar foot. A spectrum of pathology can occur in these regions. At the lower leg, peroneus longus muscle injuries (e.g., denervation) along with retromalleolar tendon instability/subluxation will be discussed. More distally, along the lateral calcaneus and cuboid tunnel, peroneus longus tendinosis and tears, tenosynovitis, and painful os peroneum syndrome (POPS) will be covered. Pathology of the peroneus longus will be illustrated using clinical case examples along its entire length; these will help the radiologist understand and interpret common peroneus longus disorders.

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

We report the case of a 55-year-old male patient who presented to the emergency department after sustaining a right ankle trauma. Swelling and tenderness of the lateral aspect of the right ankle were present on physical examination without evidence of motor or sensory deficit. Ankle radiographs were performed and showed two bony fragments, the first located postero-inferiorly to the cuboid bone while the second was adjacent to the tip of the lateral malleolus. The diagnosis of an os peroneum fracture was made with high suspicion of an associated peroneus longus tendon rupture. Computed tomography (CT) and magnetic resonance imaging (MRI) of the right ankle confirmed the diagnosis of a subtotal retracted tendinous rupture. Successful surgical repair of the injured tendon was performed. This article illustrates the imaging findings of an os peroneum fracture with its associated tendinous injury and reviews the literature.