Assessment of knee instability in ACL-injured knees using weight-bearing computed tomography (WBCT): a novel protocol and preliminary results.

OBJECTIVE: To propose a protocol for assessing knee instability in ACL-injured knees using weight-bearing computed tomography (WBCT). MATERIALS AND METHODS: We enrolled five patients with unilateral chronic ACL tears referred for WBCT. Bilateral images were obtained in four positions: bilateral knee extension, bilateral knee flexion, single-leg stance with knee flexion and external rotation, and single-leg stance with knee flexion and internal rotation. The radiation dose, time for protocol acquisition, and patients' tolerance of the procedure were recorded. A blinded senior radiologist assessed image quality and measured the anterior tibial translation (ATT) and femorotibial rotation (FTR) angle in the ACL-deficient and contralateral healthy knee. RESULTS: All five patients were male, aged 23-30 years old. The protocol resulted in a 16.2 mGy radiation dose and a 15-min acquisition time. The procedure was well-tolerated, and patient positioning was uneventful, providing good-quality images. In all positions, the mean ATT and FTR were greater in ACL-deficient knees versus the healthy knee, with more pronounced differences observed in the bilateral knee flexion position. Mean lateral ATT in the flexion position was 9.1±2.8 cm in the ACL-injured knees versus 4.0±1.8 cm in non-injured knees, and mean FTR angle in the bilateral flexion position was 13.5°±7.7 and 8.6°±4.6 in the injured and non-injured knees, respectively. CONCLUSION: Our protocol quantitatively assesses knee instability with WBCT, measuring ATT and FTR in diverse knee positions. It employs reasonable radiation, is fast, well-tolerated, and yields high-quality images. Preliminary findings suggest ACL-deficient knees show elevated ATT and FTR, particularly in the 30° flexion position.

Imaging of progressive collapsing foot deformity with emphasis on the role of weightbearing cone beam CT.

The term progressive collapsing foot deformity (PCFD) is currently recommended as the replacement to adult-acquired flatfoot deformity and posterior tibial tendon dysfunction to better reflect its pathology, which consists of a complex three-dimensional deformity involving the foot and ankle. The new consensus has also provided a new classification that requires clinical and radiographic findings for patient stratification into each class. However, conventional radiographs are susceptible to errors resulting from the inadequate positioning of patients, incorrect angulation of the X-ray tube, and overlapping of bone structures. Weightbearing cone beam computed tomography (WBCBCT), which has greater diagnostic accuracy than conventional radiograph, is useful for evaluating progressive collapsing foot deformity to determine medial arch collapse, hindfoot alignment, peritalar subluxation, posterior subtalar joint valgus, intrinsic talus valgus, and lateral extra-articular bone impingement. The present review aimed to discuss the new recommendations for nomenclature, classification, and imaging evaluation of PCFD, with an illustrative and quantitative focus on the measurements used in conventional radiography and WBCBCT. The measurements presented here are important criteria for decision-making.

Computed tomography (CT), X-ray, and MRI evaluation of two anterolateral knee reconstruction techniques: lateral extra-articular tenodesis (LET) and the anterolateral ligament (ALL) reconstruction.

The anterolateral ligament (ALL) and capsule of the knee are anatomical structures involved in rotational stability and pivot-shift control. As such, it has been demonstrated that the extra-articular anterolateral procedures improve clinical outcome when performed as an augmentation of the anterior cruciate ligament (ACL) reconstruction in specific groups of patients. This review describes the postoperative imaging findings of two techniques used to perform these procedures, using magnetic resonance imaging (MRI), computed tomography (CT), and radiography. The first technique described is the lateral extra-articular tenodesis (LET), which uses a strip of the iliotibial band that is harvested, passed underneath the lateral collateral ligament (LCL) and fixed posterior, and proximal to the lateral femoral epicondyle (LFE), preserving ITB insertion on Gerdy's tubercle. The second technique described is the ALL reconstruction, a procedure that attempts to recreate the anatomy of the ALL, using most often a gracilis autograft. In this procedure, femoral fixation is performed proximal and posterior to the LFE, and tibial fixation is slightly distal to the joint line, halfway from Gerdy's tubercle to the fibular head. The main objective of this review is to provide an overview of the postoperative imaging aspects of these two procedures with MRI, CT, and radiography and to describe possible complications. As they become more common, it is important for the radiologist and the orthopedic surgeon to understand their particularities in combination with the already well-known ACL reconstruction.

Hindfoot Alignment in Flexible Cavovarus Deformity Under Orthostatic and Coleman Block Test Positions: A Weightbearing Computed Tomography Study.

BACKGROUND: Flexible cavovarus deformity is prevalent and the Coleman block test is frequently used to assess the first ray plantarflexion malpositioning in the overall deformity as well as the flexibility of the hindfoot. The objective was to assess and compare the weightbearing computed tomography (WBCT) 3-dimensional (3D) changes in clinical and bone alignment in flexible cavovarus deformity patients when performing the Coleman block test when compared to normal standing position and to controls. METHODS: Twenty patients (40 feet) with flexible cavovarus deformity and 20 volunteer controls (40 feet) with normal foot alignment underwent WBCT imaging of the foot and ankle. Cavovarus patients were assessed in normal orthostatic and Coleman block test positions. Foot and ankle offset (FAO), hindfoot alignment angle (HAA), talocalcaneal angle (TCA), subtalar vertical angle (SVA) and talonavicular coverage angle (TNCA) and a CT-simulated soft tissue envelope image, WBCT clinical hindfoot alignment angle (WBCT-CHAA), were evaluated by 2 readers. Measurements were compared between cavovarus nonstressed and stressed positions and to controls. P values of .05 or less were considered significant. RESULTS: The intra- and interobserver intraclass correlation coefficient were good or excellent for all WBCT measurements. Cavovarus patients demonstrated significant correction of WBCT-CHAA (9.7 ± 0.4 degrees), FAO (2.6 ± 0.4%), and TNCA (8.8 ± 1.8 degrees) when performing the Coleman block test (all P values <.0001). However, WBCT-CHAA and FAO measurements were still residually deformed and significantly different from controls (P values of .001 and <.0001, respectively). TNCA values corrected to values similar to healthy controls (P = .29). No differences were observed in cavovarus patients during Coleman block test for the coronal measures: HAA, TCA, and SVA measurements. CONCLUSION: In this study, we observed improvement in the overall 3D WBCT alignment (FAO), axial plane adduction deformity (TNCA), as well as CT simulated clinical hindfoot alignment (WBCT-CHAA) in flexible cavovarus deformity patients when performing a Coleman block test. However, we did not find improvement in measures of coronal alignment of the hindfoot, indicating continued varus positioning of the hindfoot in these patients. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Imaging of solitary and multiple osteochondromas: From head to toe - A review.

Osteochondromas account for 20%-50% of all benign bone lesions. These tumors may present as solitary non-hereditary lesions, which are the most common presentation, or as multiple tumors associated with hereditary conditions. Plain radiography is the imaging method of choice and demonstrates the typical cortical and medullary continuity of the tumor with the underlying bone. Magnetic resonance imaging is often performed to evaluate cartilage cap thickness, which correlates with malignant transformation. Other local complications include compression of adjacent neurovascular bundles, muscles, and tendons, bursitis, tendon tears, stalk fracture, and angular or rotational long bone deformities. Although the imaging features of osteochondromas are largely known, only a few papers in the literature have focused on their main complications and image-based follow-up. This paper aimed to illustrate the main complications of osteochondromas, suggest an image-based algorithm for management and follow-up and discuss differential diagnosis.

WEIGHT-BEARING CONE BEAM CT SCANS AND ITS USES IN ANKLE, FOOT, AND KNEE: AN UPDATE ARTICLE.

Imaging plays a key role in the preoperative diagnosis, surgical planning, and postsurgical assessment of the foot, ankle, and knee pathologies. Interpreting diagnostic imaging accurately is crucial for the clinical practice of orthopedic surgeons. Although among the most used imaging modalities, radiographic assessments are amenable to errors for various technical reasons and superposition of bones. Computed tomography (CT) is a conventional imaging procedure that provides high-resolution images, but fails in considering a truly weight-bearing (WB) condition. In an attempt to overcome this limitation, WB cone beam CT technology has being successfully employed in the clinical practice for the past decade. Besides economically viable and safe, the WB cone beam CT considers WB conditions and provides high-quality scans, thus allowing an equitable and correct interpretation. This review aims to address extensive description and discussion on WBCT, including imaging quality; costs; time consumption; and its applicability in common foot, ankle, and knee, conditions. With this technology increasing popularity, and considering the extensive literature on medical research, radiologists and orthopedic surgeons need to understand its potential applications and use it optimally. Level of Evidence III, Systematic review of level III studies.

Os exames de imagem são essenciais no diagnóstico, planejamento cirúrgico e avaliação pós-cirúrgica das patologias que envolvem pé, tornozelo e joelho. A interpretação acurada utilizando as tecnologias de diagnóstico por imagem disponíveis é crucial para os cirurgiões ortopédicos na sua prática clínica. Embora as radiografias convencionais estejam entre as modalidades de diagnóstico por imagem mais utilizadas, elas estão sujeitas a erros por várias razões técnicas e sobreposição de estruturas ósseas. Apesar de a tomografia computadorizada (TC) fornecer imagens de alta qualidade, ela falha em não considerar a carga corporal fisiológica. A TC de feixe cônico com carga vem sendo utilizada com sucesso desde a última década, superando a limitação da TC convencional. Além de ser econômica e segura, possibilita a aquisição de imagens de alta resolução, com carga, permitindo, assim, uma interpretação correta e equiparável. O objetivo principal dessa revisão é proporcionar uma discussão e descrição ampla de TC com carga, incluindo qualidade de imagem, custos financeiros, tempo consumido em exames, e suas aplicações em patologias comuns do pé, tornozelo e joelho. A TC com carga vem crescendo em popularidade, e é tema de um número extenso de pesquisas científicas, sendo necessário que radiologistas e cirurgiões ortopédicos entendam suas aplicações para melhor uso futuro. Nível de Evidência III, Revisão sistemática de Estudos de Nível III.

Weight-bearing cone-beam computed tomography in the foot and ankle specialty: where we are and where we are going - an update.

Cone-beam computed tomography (CBCT) has been applied in dentistry and medicine for nearly two decades. Its application in the foot and ankle specialty has grown exponentially in recent years. Weight-bearing CBCT allows clinicians to obtain weight-bearing images that can be viewed in all three planes and to construct three-dimensional models, similar to those constructed from traditional CT scans, as well as exposing patients to less radiation than do traditional CT scans. This technology has revolutionized diagnoses, improving the understanding of various lesions and surgical planning in the foot and ankle specialty. Ongoing studies of the use of weight-bearing CBCT in foot and ankle surgery are focused on fully automated and semi-automated three-dimensional measurements, as well as bone segmentation, mapping of the distances/orientation of the joints, and the production of customized implants. The aims of this review article are to show the evolution of this emerging tool in the foot and ankle specialty, to update those in related specialties on its use in current clinical practice, and to indicate where the research community is heading.

A tomografia computadorizada (TC) de feixe cônico é aplicada na área da odontologia e medicina há cerca de duas décadas, e seu uso na especialidade do tornozelo e pé cresceu de forma exponencial nos últimos anos. A literatura demonstra como a TC de feixe cônico permite obter imagens com apoio do peso corporal total - weight-bearing cone-beam computed tomography - com cortes nos três planos e modelos tridimensionais semelhantes às TCs, associada a menor exposição à radiação, técnica que revolucionou o diagnóstico, o entendimento de diferentes lesões e o planejamento cirúrgico nessa área do conhecimento. As mensurações tridimensionais automáticas e semiautomáticas, a segmentação óssea, o mapeamento das distâncias e orientações articulares e a possibilidade de produção de implantes customizados são o interesse dos estudos em andamento na cirurgia do tornozelo e pé relacionados a essa ferramenta emergente. O objetivo deste artigo é mostrar a evolução do método, atualizar as especialidades de interface sobre uso na prática clínica atual e indicar para onde a comunidade científica está caminhando.

The role of MRI in evaluation of arthroscopic transtibial pullout repair for medial meniscus posterior root tears.

Medial meniscus posterior root tears (MMPRT) can lead to meniscal extrusion, loss of hoop tension, loss of load-sharing ability and increased contact pressure. Currently, the most commonly used technique for root repair is arthroscopic transtibial pullout repair (ATPR). This article aims to illustrate both normal and abnormal postoperative imaging findings of the MMPRT repair performed with ATPR, with emphasis on MRI. The radiologist must highlight the tunnel position, the reduction of the medial meniscus posterior root to its anatomical attachment, the signs of root healing (continuity and lower signal intensity), and eventual meniscal extrusion or signs of osteoarthritis.

Arteriopathy in pediatric stroke: an underestimated clinical entity.

BACKGROUND: Pediatric arterial ischemic stroke (AIS), which was thought to be a rare disorder, is being increasingly recognized as an important cause of neurological morbidity, thanks to new advances in neuroimaging. OBJECTIVE: The aim of this study was to review the main etiologies of stroke due to arteriopathy in children. METHODS: Using a series of cases from our institution, we addressed its epidemiological aspects, physiopathology, imaging findings from CT, MR angiography, MR conventional sequences and MR DWI, and nuclear medicine findings. RESULTS: Through discussion of the most recent classification for childhood AIS (Childhood AIS Standardized Classification and Diagnostic Evaluation, CASCADE), we propose a modified classification based on the anatomical site of disease, which includes vasculitis, varicella, arterial dissection, moyamoya, fibromuscular dysplasia, Takayasu's arteritis and genetic causes (such as ACTA-2 mutation, PHACE syndrome and ADA-2 deficiency). We have detailed each of these separately. Conclusions: Prompt recognition of AIS and thorough investigation for potential risk factors are crucial for a better outcome. In this scenario, neurovascular imaging plays an important role in diagnosing AIS and identifying children at high risk of recurrent stroke.

Arteriopathy in pediatric stroke: an underestimated clinical entity / Arteriopatia em crianças com acidente vascular cerebral: uma entidade clínica subestimada

ABSTRACT Background: Pediatric arterial ischemic stroke (AIS), which was thought to be a rare disorder, is being increasingly recognized as an important cause of neurological morbidity, thanks to new advances in neuroimaging. Objective: The aim of this study was to review the main etiologies of stroke due to arteriopathy in children. Methods: Using a series of cases from our institution, we addressed its epidemiological aspects, physiopathology, imaging findings from CT, MR angiography, MR conventional sequences and MR DWI, and nuclear medicine findings. Results: Through discussion of the most recent classification for childhood AIS (Childhood AIS Standardized Classification and Diagnostic Evaluation, CASCADE), we propose a modified classification based on the anatomical site of disease, which includes vasculitis, varicella, arterial dissection, moyamoya, fibromuscular dysplasia, Takayasu's arteritis and genetic causes (such as ACTA-2 mutation, PHACE syndrome and ADA-2 deficiency). We have detailed each of these separately. Conclusions: Prompt recognition of AIS and thorough investigation for potential risk factors are crucial for a better outcome. In this scenario, neurovascular imaging plays an important role in diagnosing AIS and identifying children at high risk of recurrent stroke.

RESUMO Introdução: O acidente vascular cerebral (AVC) pediátrico, considerado um distúrbio raro, está sendo cada vez mais reconhecido como importante causa de morbidade neurológica, graças aos novos avanços na neuroimagem. Objetivo: Revisar as principais etiologias do AVC por arteriopatia em crianças. Métodos: Utilizando-se de uma série de casos de nossa instituição, abordamos seus aspectos epidemiológicos, fisiopatológicos e de imagem na angiotomografia computadorizada e angiorressonância magnética, sequências convencionais e avançadas de ressonância magnética e medicina nuclear. Resultados: Com base na classificação mais recente de AVC na infância (Classificação Padronizada e Avaliação Diagnóstica do AVC na Infância - CASCADE) propusemos uma classificação modificada com base no local anatômico da doença, que inclui vasculite, varicela, dissecção arterial, Moyamoya, displasia fibromuscular, arterite de Takayasu e causas genéticas (como mutação ACTA-2, síndrome PHACE e deficiência de ADA-2), detalhando cada uma separadamente. Conclusões: O reconhecimento imediato do AVC na infância e a investigação minuciosa de possíveis fatores de risco são cruciais para um melhor resultado. Nesse cenário, a imagem neurovascular desempenha papel importante no diagnóstico de AVC e na identificação de crianças com alto risco de recorrência.