MR imaging of the paediatric foot and ankle

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.

Are you sure that ankle is just sprained? A review of common ankle conditions, diagnoses and treatment

PURPOSE OF REVIEW

Acute ankle sprains frequently occur in active children and adolescents but may be the initial clinical presentation of other less common disorders affecting the lower extremities. There are many conditions that may cause one or multiple episodes of ankle injury that are misdiagnosed as an acute ankle sprain. This manuscript highlights diagnoses that should be considered when evaluating and managing a child or adolescent who presents initially and/or repeatedly with an acute ankle sprain.

RECENT FINDINGS

In recent years, various studies have continued to note the prevalence of misdiagnosed ankle sprains, especially amongst the paediatric population. If ankle radiographs demonstrate no abnormalities during an initial clinical examination, often the patient is diagnosed with an acute ankle sprain. However, this can be a misdiagnosis, especially when the patient has had recurrent episodes of ankle injury and ancillary studies are not performed.

SUMMARY

There are many diagnoses that can go unnoticed in the initial evaluation of a paediatric or adolescent ankle sprain. It is important for physicians to be aware of these other conditions to ensure proper treatment plans. This manuscript will analyse five conditions that may be misdiagnosed as an ankle sprain, including juvenile idiopathic arthritis, osteochondritis dissecans of the talus, hereditary sensory motor neuropathy (Charcot-Marie Tooth disease), tarsal coalition and transitional ankle fractures.

Bone marrow oedema syndrome of the foot and ankle in a paediatric population: a retrospective case series with serial MRI evaluation

PURPOSE

By means of a case series we wanted to describe and correlate the clinical and imaging features of bone marrow oedema syndrome (BMOS) of the foot and ankle in children.

METHODS

A retrospective data study was performed on patients born on or after 01 January 2001 who underwent multiple MRI scans of the foot and ankle for pain symptoms. Six patients who presented with increased signal intensity on T2-weighted MR imaging without any underlying causes or concomitant pathology were included.

RESULTS

All patients, three boys and three girls with a mean age of 11 years (8 to 14), displayed patchy areas of increased signal intensity on T2-weighted and turbo inversion recovery magnitude (TIRM) images. On average, six tarsal bones were involved (4 to 8). In all patients, treatment consisted of rest and/or protected weight-bearing. The mean time for symptoms to improve during treatment was 6 months (1 to 16). The mean duration of treatment was nine months (3 to 16). In all patients clinical and imaging symptoms were strongly correlated and regressed in time.

CONCLUSION

BMOS as a pathological entity should be considered in paediatric patients with foot and ankle pain without a clear underlying cause, and characteristic T2-weighted and TIRM signal intensity increase on MRI images. As BMOS is transient and self-limiting, conservative treatment is advised while the oedema regresses. An early diagnosis of this pathology could prevent unnecessary diagnostic investigations and invasive treatments.

LEVEL OF EVIDENCE

IV.

Bone scan with SPECT/CT in children with complex foot and ankle pain: Initial experience of a paediatric tertiary referral centre

PURPOSE

This study was designed to review the diagnostic yield of single photon emission computed tomography-computed tomography (SPECT/CT) in children with complex foot/ankle pain.

METHODS

We reviewed the records of 33 patients with complex foot and ankle pain referred for SPECT/CT (36 scans) performed between 1st September 2009 to 30th September 2019. All patients had foot and ankle radiographs and 18 out of 33 patients had undergone magnetic resonance imaging (MRI) prior to SPECT/CT. The diagnostic contribution of SPECT/CT was established at the time of the scan during a multi-disciplinary team meeting.

RESULTS

The patients' mean age was 13.4 years (range six to 16.5 years) and 58% were female. In total, 18 patients had undergone previous surgical treatment. SPECT/CT was found to have decisive clinical value compared with radiographs and CT/MRI in 28 out of 36 cases. In ten patients it prompted surgical management (coalition excision, arthrodesis), in seven patients it redirected conservative management, in six patients it excluded other pathology and in five patients it showed additional/unexpected focal areas of mechanical stress, thus avoiding surgery. When compared with MRI, SPECT/CT added further clinical information in 13 out of 18 cases. SPECT/CT added decisive clinical value in five out of five patients with accessory ossicles, eight out of nine patients with tarsal coalition, five out of seven patients with surgically treated Congenital Talipes Equinovarus (CTEV) and four out of five patients with neuromuscular feet. In eight out of 36 cases SPECT/CT confirmed the diagnosis without adding significant information.

CONCLUSIONS

SPECT/CT can identify foci of active mechanical stress at cortical bone level in children with unexplained complex foot and ankle pain, particularly in the multiply operated foot, accessory ossicles and tarsal coalitions.

LEVEL OF EVIDENCE

IV.

Pediatric navicular dorsal osteochondroma: a rare case of navicular-cuneiform impingement

Osteochondroma is one of the most common benign bone tumors; however, as it rarely affects any bones in feet, it may easily escape detection without rigorous examination. We present an exceptionally rare case of tarsal navicular dorsal osteochondroma diagnosed in an 11-year-old female child affected by chronic foot pain. Radiographs, MRI, and computed tomography scan revealed bony excrescences extending outward from the navicular bone. After conservative treatment failed, the navicular dorsal exostosis was excised in open surgery with complete resolution of symptoms. Navicular-cuneiform impingement was diagnosed by instrumental and intraoperative techniques. Histological analysis confirmed the diagnosis of navicular dorsal osteochondroma. This case report illustrates the necessity of particularly rigorous evaluation of the substrates of pediatric chronic foot pain.

Radiographic Anatomy of the Pediatric Lisfranc Joint

BACKGROUND

Injuries to the Lisfranc joint in children and adolescents are rare. The incomplete ossification of the bones of the foot makes it difficult to detect injuries.The aim of this study was to determine age-specific radiographic measurements of the Lisfranc joint to provide guidance to the radiologist, emergency physicians, and surgeons to decrease misdiagnosis of Lisfranc injuries and improve detection.

METHODS

We retrospectively reviewed all foot radiographs without traumatic injury made between August 2014 and February 2015 in all patients younger than 18. The attendance list of the Emergency Department and Outpatient Clinic of a level-1 trauma center were used. Using a non-weight-bearing anteroposterior-view of the foot the distance between the base of metatarsal 1 and metatarsal 2 (MT1-MT2) and the distance between the medial cuneiform (MC) and the base of metatarsal 2 (MC-MT2) were measured. Median normal values were calculated per age.

RESULTS

A total of 352 patients between the age of 0 and 18 years were screened for eligibility. Excluded were 109 patients because of anatomic abnormality, a fracture, inadequate radiograph, pain at the base of the first metatarsal, second metatarsal or MC, persisting pain at the Outpatient Clinic checkup or no follow-up. Included in the analysis were 243 patients.

CONCLUSIONS

The distance between the base of MT1-MT2 was constant below 3 mm. Measurements for both MT1-MT2 and MC-MT2 distance approached adult values at the age of 6.

LEVEL OF EVIDENCE

Level III.

Diagnosing Infection in a Neonate Using Whole-Body Screening Magnetic Resonance Imaging

The location of invasive infections is difficult to detect in infants, in part due to their inability to localize signs and symptoms. However, identifying the location often significantly alters clinical management by extending the duration of antibiotic therapy or revealing a source requiring surgical intervention. Compared with commonly used first-line imaging techniques such as radiographs and ultrasounds, MRI has higher sensitivity for identifying invasive infections and allows for simultaneous evaluation of multiple foci. We present 2 cases in which whole-body screening MRI was used in neonates to identify invasive sources of infection, including one in which traditional modalities failed to detect multiple clinically significant sources. We posit that whole-body screening MRI merits consideration as a potential first-line imaging method when investigating invasive infections in infants.

Imaging appearances of soft-tissue tumors of the pediatric foot: review of a 15-year experience at a tertiary pediatric hospital

Tumors of the foot are rare in children. In this review the authors illustrate radiographic, sonographic and MR imaging findings of foot soft-tissue tumors in children based on all cases presenting at a tertiary pediatric hospital during the 15-year period of 1999-2014. Among these cases there were 155 tumors of the foot - 72 of the bones and 83 of the soft tissues. Vascular malformations, fibromatosis and sarcomas were respectively the most frequent benign, intermediate and malignant soft-tissue tumors. Some tumors showed specific imaging findings. In imaging investigations, ultrasound can be used as the first imaging modality for diagnostic workup of most lesions because it is noninvasive, low-cost and readily available, and can confirm the presence of the mass and evaluate cystic components, especially in young children who would otherwise require sedation for MR imaging. MR imaging is the reference standard technique because of its high tissue contrast, which allows for detection and characterization of soft-tissue and bone abnormalities. MR imaging is useful as the first imaging modality in select cases, including those with high suspicion of malignancy, very large lesions or pre-treatment lesions. Recognition of some typical imaging findings in pediatric soft-tissue foot tumors is helpful to establish diagnosis and facilitate patient management.