Calcaneus secundarius presenting as calcaneonavicular coalition: a case report

Symptomatic Accessory Ossicles of the Foot and Ankle

Accessory ossicles are small noncalcified, calcified or ossified structures found throughout the body, often noted as incidental findings. Specifically in the foot and ankle, there are at least 24 different ossicles described the majority of which are incidental. However, there are accessory ossicles that can be symptomatic, leading to significant pain and discomfort. While many of the symptomatic ossicles have been described in the literature, there are several that are under-recognized or under-reported for example, os interphalangeus and os calcaneus secundarius syndromes. This manuscript will review common and uncommon accessory ossicles including painful os peroneum, os naviculare, os calcaneus secundarius, os trigonum and os interphalangeus syndromes as well as medial sesamoiditis, with attention to the clinical and imaging findings and with an outline of the current management.

Accessory Ossicles in the Region of the Foot and Ankle: An Epidemiologic Survey in a Jordanian Population

Background and Objectives: The incidence of accessory bones in the region of foot and ankle is quite variable between studies and are often confused with avulsion fractures in trauma patients with musculoskeletal injuries. The aim of this study was to assess the incidence of accessory ossicles of the foot and ankle according to gender, side and coexistence, and to determine how frequently accessory ossicles were misdiagnosed as avulsion fractures. Materials and Methods: Oblique and/or lateral foot radiographs of 1000 adult patients referred from emergency departments to foot and ankle clinic were retrospectively reviewed for the presence of accessory ossicles. The Kappa statistic was used in order to assess the validity of radiographic interpretation for the presence of these bones. Results: Accessory ossicles were detected in 40.2% of the radiographs. The incidence rates for the accessory ossicles in order of frequency were: Os trigonum (15.4%), accessory navicular (13.7%), os peroneum (11.5%), os vesalianum (1.1%), os supranaviculare (0.7%), os subfibulare (0.6%), os talotibiale (0.4%), os calcaneus secundarius (0.3%), os supratalare (0.3%), os infranaviculare (0.3%), os intermetatarseum (0.2%), and os subtibiale (0.1%). Coexistence of two or three ossicles in the same foot was observed in 4.4% of the cases, mostly coexistence with os peroneum (2.9%), followed by accessory navicular (1.6%). 2.7% of accessory ossicles were initially misdiagnosed as avulsion fractures at emergency departments. Interrater agreement over identification of different accessory ossicles was found to be reasonably reliable, with a Kappa greater than 0.80 for all assessed bones. Conclusions: In clinical practice, a thorough knowledge of normal anatomical variants is essential to facilitate appropriate diagnosis and treatment and can help to prevent diagnostic errors.

A case of an injured calcaneus secundarius in a professional soccer player

Background

The calcaneus secundarius (CS) is an accessory ossicle of the anterior facet of the calcaneus and is usually asymptomatic. This accessory bone can be frequently mistaken for a fracture of the anterior process of the calcaneus. Few reports of symptomatic CS have been published, and physicians need to be familiar with imaging strategies when encountering chronic ankle pain or in case of suspicion of fracture of the anterior process of the calcaneus.

Case presentation

We describe the case of symptomatic CS in a professional soccer player injured during a match. First, computed tomography showed a large CS. Second, magnetic resonance imaging (MRI) demonstrated synchondrosis between the CS and the calcaneus, as well as edema (high MR T2 signal) within it, corresponding to posttraumatic edema. The patient was successfully treated with nonsteroidal anti-inflammatory drugs and physiotherapy; no surgical management was necessary. At the 4-week follow-up, he was pain-free and returned to activity.

Conclusion

This case illustrates the role of imaging for the diagnosis of CS in cases of acute pain of the foot. CT, as well as MRI, helped to confirm the diagnosis of CS traumatized synchondrosis, which can be mistaken for a fracture.

Os calcaneus secundarius, a relevant differential diagnosis to fracture or pseudarthrosis of processus anterior of the calcaneus: a CT morphologic description

PURPOSE

A fracture or a pseudarthrosis of the processus anterior calcanei (PAC) as well as a traumatized Os calcaneus secundarius (OCS) is often overlooked. A clinical or conventional radiological differentiation of these is uncertain. Therefore, a CT scan is recommended. The aim of the study was to identify CT morphological differentiators between OCS and pathologies of PAC.

METHODS

All CT scans at our trauma center level I from 2010 to 2014, which imaged the entire foot, performed after acute trauma or postoperative control were retrospectively re-examined for OCS, other accessory ossicles (oAOS), fracture or pseudarthrosis of PAC and analyzed for specifiers.

RESULTS

In 611 CT examinations, 14 (2.3%) accessory ossicles (AOS) at the PAC were detected. 12 (86%) were identified as typical OCS and 2 (14%) as oAOS. 56 (9.2%) pathologies were detected. Of these, 44 (79%) were declared as fractures and 12 (21%) as pseudarthrosis. 7 OCS (58%) and 25 (46%) of the pathologies were not mentioned in the initial CT reports. The main differentiators of OCS to fracture of PAC were the anteromedial localization into a concave notch at the calcaneal facet at PAC and the continuous corticalization. With increasing size, radiological osteoarthritic signs at the OCS were frequent (p ≤ 0.05).

CONCLUSIONS

The study confirms that AOS or pathologies at the PAC often are not exactly described in CT report. In the context of foot trauma, attention should be paid to this region. Based on the presented differentiation criteria, a precise distinction can be made with the help of a CT.

Anatomical variation in the ankle and foot: from incidental finding to inductor of pathology. Part I: ankle and hindfoot

Accessory anatomical structures in the ankle and foot usually represent incidental imaging findings; however, they may also eventually represent a source of pathology, such as painful syndromes, degenerative changes, be the subject of overuse and trauma or appear as masses and cause compression syndromes or impingement.This review aims to describe and illustrate the imaging findings related to the presence of accessory ossicles and muscles in the ankle and hindfoot through different techniques, with special attention to those variants that associate factors of clinical relevance or that trigger challenges in the differential diagnosis.

Tibial spastic varus foot caused by os calcaneus secundarius: A case report

Peroneal spastic flatfoot caused by tarsal coalition is well known; however, tibial spastic varus foot is a rare clinical entity also caused by tarsal coalition in most cases. The os calcaneus secundarius is a rare accessory bone between the anterior process of the calcaneus and the navicular bone. The case of a 29-year-old woman with tibial spastic varus foot caused by os calcaneus secundarius is presented. Operative excision of the os calcaneus secundarius completely resolved the varus deformity. This is the first case report involving tibial spastic varus foot caused by os calcaneus secundarius.

Endoscopic resection of symptomatic os calcaneus secundarius

Os calcaneus secundarius is an accessory ossicle resulting from a secondary ossification center of the anterior facet of the calcaneus. It may cause chronic pain and limitation in inversion motion after inversion ankle sprain. Excision of the ossicle is indicated if the symptoms do not resolve with conservative treatment. A case of symptomatic os calcaneus secundarius, which was successfully resected endoscopically, is presented.

Calcaneus secundarius--a relevant differential diagnosis in ankle pain: a case report and review of the literature

Introduction

Accessory ossicles of the foot are a common finding. Although mostly asymptomatic, they can gain clinical relevance by trauma or stress on the complex biomechanical system of the foot. There are few reports on the entity of symptomatic calcaneus secundarius. Furthermore, the current literature does not address the need for awareness of calcaneus secundarius as a differential diagnosis in cases of persistent posttraumatic ankle pain.

Case presentation

We present the case of a 51-year-old Indo-European man with a medical history of persistent load-dependent ankle pain over 3 decades. At presentation after an acute ankle sprain, we diagnosed a traumatized calcaneus secundarius. Surgical excision led to a complete recovery. More than 1 year postoperative he is still asymptomatic.

Conclusions

With the presented case and review of the literature we demonstrate the clinical relevance of calcaneus secundarius. Depending on size and alignment, calcaneus secundarius can alter the biomechanics in the subtalar region generating pain at the ankle. If a patient has persistent sinus tarsi syndrome, a painful limited subtalar range of motion or repetitive ankle sprains, then calcaneus secundarius should be considered in differential diagnosis. Likewise when a fracture of the anterior process of the calcaneus or a calcaneonavicular coalition is suspected, calcaneus secundarius should be considered a possible diagnosis by all clinicians confronted with foot and ankle pain.

Three-Dimensional CT Findings of Os Calcaneus Secundarius Mimicking a Fracture

Os calcaneus secundarius is one of several accessory ossicles of the foot that have been identified as normal variants of skeletal development. It may cause ankle pain and may mimic an avulsion fracture of the anterior calcaneal process. A twenty-year-old male was admitted to our institution with right ankle pain following an inversion injury. An axial CT image of the patient's right ankle revealed a shape with smooth and sharp margins, identified as a well-corticated bone fragment in the subtalar region. A diagnosis of an accessory ossicle, os calcaneus secundarius, was made based on radiographic findings. As a result of this case, it is recommended that potential locations of the accessory bones should be well understood in order to prevent misdiagnosis and inappropriate surgical procedures. Os calcaneus secundarius must be considered when an apparent bone fragment or a suspicious fracture line at the anterior region of os calcaneus is demonstrated.

Imaging of tarsal navicular disorders: a pictorial review

The tarsal navicular is a bone within the midfoot that plays a critical role in maintaining the arch of the foot. This bone is clinically relevant because it may be affected by a wide array of pathologies. Our approach includes a detailed description of the imaging characteristics and disorders affecting the tarsal navicular. Organization includes (a) normal imaging, (b) accessory ossicles, (c) coalition, (d) fractures, (e) Kohler's disease, (f) osteonecrosis, (g) osteochondral lesions, (h) arthropathies, and (i) tumors. The purpose of this article is to discuss normal variants and pathological processes that can affect the tarsal navicular, with emphasis on the often-overlooked imaging findings.

A review of tarsal coalition and pes planovalgus: clinical examination, diagnostic imaging, and surgical planning

Pediatric pes planovalgus deformity may be classified as flexible or rigid. The rigid pes planovalgus is often a result of a tarsal coalition, which is typically characterized as a painful unilateral or bilateral deformity, frequently associated with peroneal spasm. However, many tarsal coalitions are asymptomatic and demonstrate no peroneal spasm or pes planovalgus deformity. Likewise, the severe pes planovalgus foot type can demonstrate some of the same clinical and radiographic features of a tarsal coalition, especially in the obese adolescent patient. Also, peroneal spasm may occur in the noncoalesced foot, making diagnosis and etiology more difficult to elucidate. The authors believe that many patients with a pes planovalgus deformity lie in this "gray zone": somewhere between the frank osseous coalition and the flexible pes planovalgus. The "step-forward Hubscher maneuver" is introduced as an effective means of evaluating the flexibility of a pes planovalgus foot by negating the effects of a gastrocnemius or gastrocnemius-soleus equinus. This article focuses on the clinical examination and findings of specific imaging studies to assist in an accurate diagnosis of these complicated patients. This will also help to reveal the various surgical options that are appropriate for the individual patient. Emphasis is placed on computerized tomography (CT) imaging and offers enhanced methods for ordering this test to specifically evaluate middle facet coalitions of the subtalar joint. The authors also introduce "lateral tarsal wedging," an image finding associated with severe deformities, the implications of this finding, as well as its impact on surgical planning.

Anterior process calcaneal fractures: a systematic evaluation of associated conditions

OBJECTIVE

The objective was to evaluate the association, by MRI, of anterior calcaneal process fractures with tarsal coalitions, ankle sprains, and bifurcate ligament abnormalities.

DESIGN AND PATIENTS

A retrospective review of 1,479 foot and ankle MR images was performed, over a period of 5 years, for isolated anterior process fractures of the calcaneus. Fifteen 1.5-T MR examinations were systematically evaluated by two radiologists in consensus. Marrow edema patterns, presence of a calcaneonavicular coalition, as well as bifurcate and anterior talofibular ligaments, were evaluated.

RESULTS

There were 15 fractures of the anterior calcaneal process with an incidence of 1%. The average patient age was 51 years (range 25-82). Twelve patients were women and 3 were men. The majority of the fractures (14 out of 15) presented as an edema pattern on T2-weighted images, either diffuse (9 out of 15), or vertical (5 out of 15). One case did not show marrow edema, but rather a hypointense line. Nine patients (60%) demonstrated calcaneonavicular coalition and anterior calcaneal process fracture. In 6 patients (50%) the anterior talofibular ligament (ATFL) was thickened. Three patients did not have axial images, and were classified as non-conclusive for the ATFL evaluation. The bifurcate ligament was thickened with hyperintense signal demonstrating a sprain in 9 out of 13 (69%). Only 2 patients (16.5%) had an anterior calcaneal process fracture without any associated abnormality.

CONCLUSIONS

We believe that there is a probable association of anterior process fractures and calcaneonavicular coalitions. We also feel, based on our results and the prior literature that there is likely also an association with both ATFL injuries and bifurcate ligament injuries.