Accessory ossicles of the foot-an imaging conundrum

Accessory foot bones in a Portuguese identified skeletal collection

Data from dry bone samples, collected from anatomical or archaeological collections, can improve the knowledge regarding accessory foot bones, including prevalence, size, shape and laterality, that can be useful in disparate fields of research, from medicine to bioarcheology. In the present study, the prevalence of six accessory foot bones (os trigonum, calcaneus secundarium, accessory navicular bone, os vesalianum, os sustentaculum and os intermetatarseum) was assessed in a sample of 486 individuals (226 females, 260 males) from the Coimbra Identified Skeletal Collection (CISC). The most frequent accessory bones are os trigonum (9.9%; 48/485) and calcaneus secundarium (6.0%; 29/486), while the most uncommon is os sustentaculum (0.4%; 2/486). No sex differences were observed. All accessory bones occur more often unilaterally, with the exception of the accessory navicular bone that, in the majority of cases, occurs bilaterally. The unilateral expression of os trigonum, calcaneus secundarium and os vesalianum was mostly in the right foot. The co-occurrence of accessory foot bones was recorded in 1.7% of the individuals (8/486), and the combinations of os trigonum and calcaneus secundarium were the most frequently observed. This research emphasizes the relevance of conducting studies on reference skeletal collections in order to gain a comprehensive understanding of anatomical variations in the foot. This understanding is crucial for accurate diagnoses and successful treatment in clinical settings, as well as for establishing population comparison standards in the fields of bioarchaeology and forensic anthropology.

Analysing false-positive errors when Australian radiographers use preliminary image evaluation

INTRODUCTION

Diagnostic errors in the emergency departments can have major implications on patient outcomes. Preliminary Image Evaluation (PIE) is a brief comment written by a radiographer describing an acute or traumatic pathology on a radiograph and can be used to complement referrer's image interpretation in the absence of the radiologist report. Currently, no studies exist that focus their analysis on false-positive (FP) errors in PIE. The purpose of this study was to investigate the regions of the body that cause the most FP errors and recognise other areas in image interpretation that may need additional attention.

METHODS

A longitudinal retrospective clinical audit was conducted to determine the accuracy of radiographer PIE's over 5 years from January 2016 to December 2020. PIE's were compared to the radiologist report to assess for diagnostic accuracy. FP and unsure errors were further categorised by anatomical region and age.

RESULTS

Over this period, a sample size of 11,090 PIE audits were included in the study demonstrating an overall PIE accuracy of 87.7%. Foot, ankle and chest regions caused the most FP errors, while ankle, shoulder and elbow caused the most unsure cases. 76% of the unsure cases were negative for any pathology when compared to the radiologist report. The paediatric population accounted for 21.3% of FP cases and 33.6% of unsure cases.

CONCLUSION

Findings in this study should be used to tailor education specific to radiographer image interpretation. Improving radiography image interpretation skills can assist in improving referrer diagnostic accuracy, thus improving patient outcomes.

Foot pain in children and adolescents: a problem-based approach in musculoskeletal ultrasonography

Various etiologies and risk factors contribute to foot pain in children and adolescents, including conditions such as Kohler's disease, Sever's disease, Iselin's disease, rigid flat foot, accessory navicular, Freiberg's disease, sesamoiditis, os trigonum syndrome, and more. High-frequency musculoskeletal ultrasonography can show both the bone surface and the surrounding soft tissue clearly from various angles in real-time, thereby providing a higher level of detail that is helpful for identifying the etiology of foot pain and monitoring disease progression compared with other imaging modalities. This review provides an overview of the epidemiology, pathophysiology, clinical manifestations and characteristic ultrasonographic findings of select foot pain conditions in children and adolescents.

[Radiological-nuclear medicine hybrid diagnostics with SPECT/CT for chronic foot and ankle diseases : A new and important diagnostic tool]

BACKGROUND AND AIM

In contrast to standard methods (sonography, X‑ray, CT (computed tomography), MRI (magnetic resonance imaging), numerous diseases of the foot or ankle can be diagnosed using SPECT/CT (single photon emission computed tomography/computed tomography) with regard to their clinical relevance with high accuracy (up to > 90%). The aim of this review is to provide an up-to-date overview of the importance of SPECT/CT in selected diseases of the foot and ankle.

MATERIAL AND METHODS

A literature search was carried out in the Pubmed database using the following terms: SPECT/CT, SPECT, skeletal scintigraphy, CT, computed tomography, foot and ankle disease, OSG, tarsal root, foot pain. The publications were selected with regard to questions and diagnoses that frequently occur in foot and ankle diagnostics. Furthermore, papers that describe a more precise diagnosis, a change in therapy management or a reduction in symptoms due to the use of SPECT/CT were selected.

RESULTS

Several studies have shown that a focally increased bone metabolism in osteoarthritis and osteochondral lesions correlates significantly with the development of pain. The presence of symptomatic ossicles such as the os naviculare accessorium type II and os trigonum can be clearly demonstrated with the help of SPECT/CT and cannot be assigned as the source of the symptoms as accurately with any other imaging method. Bony reactions in the area of coalitions, arthrodesis, osteosynthesis, occult fractures, prostheses and diabetic foot cannot be detected with comparable accuracy using any other imaging method, so that therapy concepts in unclear cases, based only on standard imaging are changed in up to 2/3 of cases by SPECT/CT information.

DISCUSSION AND CONCLUSION

SPECT/CT is useful when there are clinical uncertainties despite standard imaging.

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.

Os supranaviculare and navicular osteochondral lesion contributing to the development of a navicular stress fracture in an adolescent male athlete: Case report

Stress fractures of the tarsal navicular bone can be problematic in the athlete. This case details the injury and outcome of an adolescent male athlete who experienced one year of intermittent foot pain without acute trauma. Radiographs and computed tomography demonstrated a triad of a navicular stress fracture, an os supranaviculare, and an osteochondral defect of the navicular bone. The patient underwent successful operative fixation and returned to painless full function with imaging demonstrating healing at six months. Diagnosis of a navicular stress fracture in the setting of both an os supranaviculare and osteochondral lesion of the navicular bone have not been reported elsewhere in the literature. While repetitive loading on the navicular bone can independently produce a stress fracture, the patient had an increased risk for this injury; the presumably pre-existing navicular osteochondral lesion and os supranaviculare may have resulted in decreased effective articular surface area, thereby increasing force on the navicular bone and producing a stress fracture. Understanding navicular stress fractures and concomitant bony pathology contributing to injury is crucial to successful diagnosis, management, and prevention of recurrence.

Posterior Ankle Impingement Syndrome Clinical Features Are Not Associated With Imaging Findings in Elite Ballet Dancers and Athletes

OBJECTIVE

To assess the association between clinical features and magnetic resonance imaging (MRI) findings in posterior ankle impingement syndrome (PAIS) and to compare the prevalence of imaging findings between participants with and without a clinical diagnosis of PAIS.

DESIGN

Case-control study.

SETTING

Elite ballet and sport.

PARTICIPANTS

Eighty-two male (54%) and female participants comprising ballet dancers (n = 43), cricket fast bowlers (n = 24), and football (soccer) players (n = 15).

INDEPENDENT VARIABLES

Clinical: posterior ankle pain on body chart, passive plantarflexion pain provocation test. Patient-reported outcome measures: Oslo Sports Trauma Research Center Overuse Injury Questionnaire, Foot and Ankle Ability Measure Sports subscale.

MAIN OUTCOME MEASURES

Imaging findings including posterior ankle bone marrow edema, os trigonum (± bone marrow edema, and increased signal at synchondrosis), Stieda process (± bone marrow edema), talocrural and subtalar joint effusion-synovitis size, flexor hallucis longus tendinopathy, and tenosynovitis identified as present or absent on 3.0-Tesla MRI.

RESULTS

Imaging findings were not associated with posterior ankle pain or a positive ankle plantarflexion pain provocation test. Imaging findings were not associated with patient-reported outcome measures. Imaging findings did not differ between PAIS-positive and PAIS-negative groups. Os trigonum and Stieda process were prevalent despite clinical status.

CONCLUSIONS

The lack of association between imaging findings and clinical features questions the role of imaging in PAIS. Clinicians should rely primarily on clinical assessment in the diagnosis and management of patients with PAIS.

MRI for paediatric flatfoot: is it necessary?

OBJECTIVE

To determine the additional benefit of MRI for children with flatfoot deformity assessed with weight-bearing radiographs in a specialist paediatric orthopaedic unit.

METHODS AND MATERIALS

Patient cohort was obtained by searching the Radiology Information System for children referred for investigation of flatfoot. All patients with flatfoot on weight-bearing radiographs who had undergone MRI were included. Radiographs were classified by a consultant musculoskeletal radiologist as showing no underlying abnormality, talo-calcaneal coalition, calcaneonavicular coalition, accessory navicular or other abnormality. MRI studies were classified similarly by a different consultant musculoskeletal radiologist blinded to the radiographic findings.

RESULTS

33 males and 24 females were included (mean age 12.5 years; range 3-18 years). 24 had bilateral abnormality, so 81 feet were assessed. Radiographs showed no specific abnormality (n = 51), talocalcaneal coalition (n = 6), calcaneonavicular coalition (n = 3), os naviculare (n = 12) or other abnormality (n = 9). MRI showed no specific abnormality (n = 40), talocalcaneal coalition (n = 10), calcaneonavicular coalition (n = 5), os naviculare (n = 12) or other abnormality (n = 14). Assuming MRI as the diagnostic gold-standard, additional relevant diagnostic information was identified in 19 (23.5%) cases, while in the 51 cases for which radiographs provided no specific diagnosis MRI confirmed no underlying abnormality in 31 (60.8%).

CONCLUSION

MRI is a valuable adjunct to weight-bearing radiography for investigating paediatric flatfoot deformity.

ADVANCES IN KNOWLEDGE

MRI is of value in the assessment of paediatric flatfoot, additional diagnostic information to radiography being identified in 23.5% cases, while in 60.8% of cases for which radiographs provided no specific diagnosis MRI confirmed no underlying abnormality.

The hallucal interphalangeal ossicle: anatomy and basis for ultrasound-guided surgical shaving

Painful lesions on the plantar aspect of the first interphalangeal joint (IPJ) of the hallux can be attributed to structures called ossicles, nodules, or sesamoids. The aims of the present study were first to verify that ultrasonography (US) is a high-sensitivity tool for diagnosing an interphalangeal ossicle (IO), and second to prove that US-guided-shaving surgery ("milling") is a safe and feasible technique for remodeling the IO. The study is divided into three parts. In the first part, the prevalence of IOs was estimated in 12 cadaver feet using US, anatomical dissection, and fluoroscopy. In the second, a detailed US and morphological description of the IO was obtained. In the third, six cadaver feet were subjected to surgical milling. IO prevalence was 41.6% in gross anatomy, 41.6% in US examination and just 16.6% in fluoroscopy. The ossicles had a mean length of 4 mm (± 2 mm) and a width of 7 mm (± 2 mm). The ossicles could be completely shaved in all specimens without injuring important anatomical structures. Our results indicate that US is a more precise tool for diagnosing an IO than X-ray. Moreover, our US-guided mini-invasive surgical technique appears feasible and safe.

Periarticular calcifications

Periarticular calcification and ossification is a frequent finding on imaging and may sometimes pose a diagnostic challenge. The differential diagnoses for this radiological finding are wide and can be classified into broad groups such as idiopathic, developmental, trauma, burns, infection, tumor, connective tissue disease, crystalline, metabolic, vascular, and foreign bodies. With careful consideration of the clinical and imaging findings as well as awareness of mimickers of periarticular mineralization, the list of differential diagnoses can be narrowed down. This article aims to review the clinical-radiologic findings of periarticular calcified or ossified lesions with relevant imaging illustrations.

Anatomical variations and interconnections of the superior peroneal retinaculum to adjacent lateral ankle structures: a preliminary imaging anatomy study

Aim

This imaging anatomy study aimed at detecting anatomical variations and potential interconnections of the superior peroneal retinaculum to other lateral stabilizing structures.

Materials and methods

We retrospectively reviewed the imaging archives of 63 patients (38 females, 25 males, mean age 32.7, range 18–58 years) with available ankle US, MR and CT images to detect whether US and MR can detect the presence of interconnections between the superior peroneal retinaculum and the anterior talofibular ligament, inferior extensor retinaculum and peroneal tendon sheath. We evaluated the presence of common anatomical variations including low peroneus brevis muscle belly, peroneal tubercle, os peroneum, and retromalleolar fibular groove shape in relation to the presence of superior peroneal retinaculum connections.

Results

The connections of the superior peroneal retinaculum can be revealed on magnetic resonance imaging (MRI) and ultrasound (US). The connection to the anterior talofibular ligament was located (a) inferior to the lateral malleolus, (b) at the level of the lateral malleolus and (c) on both levels, respectively (a) 49.2% on MRI and 39.7% on US, p <0.05, (b) 44.4% and 58.7%, p <0.05, 36.5% and (c) 27%, p <0.05. Superior peroneal retinaculum–inferior extensor retinaculum (MRI 47.6%, US 28.6% p <0.001) and superior peroneal retinaculum–peroneal tendon sheath (MRI 22.2%, US 25.4% p >0.05) connections were also found both on MR and US.

Conclusion

Ankle US and MR revealed interconnections between the superior peroneal retinaculum and the anterior talofibular ligament, inferior extensor retinaculum, and superior peroneal retinaculum. Our results are a starting point for further studies on the connections of the superior peroneal retinaculum and the applicability of ultrasound and MRI in assessing their occurrence. Knowledge of the anatomical connections of the superior peroneal retinaculum may help radiologists with the assessment of lateral ankle injuries, and surgeons with treatment planning.

Rare injury of the foot: Os trigonum fracture: A case report

Os trigonum fractures are seen rarely. Our patient was a 16-year-old male patient who applied to our emergency service with right ankle pain due to acute hyperplantar flexion while playing football. There was a swelling on the right ankle and he had difficulty in walking. Os trigonum fracture was detected at lateral X-ray of the right ankle. No additional injury was detected with computed tomography and magnetic resonance imaging (MRI). Patient was treated conservatively. A short leg cast was applied. Cast was removed after six weeks and range of motion exercises were started. Union of fracture was seen on X-ray at six weeks from injury. Conservative treatment is thought to be a good option in these fractures. Computed tomography and MRI are important in the differential diagnosis and evaluation of additional injuries in this type of fracture.

Unsuspected Accessory Ossicle in Possible Sinus Tarsi Syndrome: The Value of Bone SPECT/CT

Three-phase bone scan was performed for evaluation of possible sinus tarsi syndrome in a 52-year-old man with chronic left ankle pain. MRI was initially read as unremarkable, and there was little symptomatic improvement after intra-articular anesthetic injection. The primary finding that appreciated only delayed bone SPECT/CT images was focal increased uptake associated with a well-corticated 8-mm bony fragment adjacent to the left calcaneus, thought to represent an accessory ossicle within the left sinus tarsi. The increased uptake suggested fracture or severe degenerative change of the ossicle, likely contributing to the patient's chronic pain.