Magnetic resonance imaging in the assessment of meniscal anatomic variants and of the perimeniscal ligamentous anatomy: potential interpretation pitfalls

O conhecimento adequado das variações anatômicas meniscais e das estruturas perimeniscais é essencial para uma avaliação adequada dos exames de ressonância magnética do joelho, tanto no diagnóstico das lesões meniscais quanto para se evitar uma série de possíveis erros diagnósticos. Este artigo revê variações anatômicas que alteram o tamanho, a forma e a estabilidade meniscais e que incluem os vários tipos de menisco discoide, outras variações morfológicas meniscais menos frequentes e o ossículo meniscal. Também é revisada a anatomia de estruturas perimeniscais, principalmente ligamentares, que incluem os ligamentos meniscocapsulares, intermeniscais, meniscofemorais e extensões meniscoligamentares.The knowledge of meniscal anatomic variants and of the normal perimeniscal structures is essential to understand magnetic resonance imaging studies of the knee, both for the diagnosis of meniscal lesions and to avoid potential interpretation pitfalls. The present article reviews anatomic variants that change the size, shape and stability of the menisci, including the different types of discoid menisci, other less frequent meniscal malformations and the meniscal ossicle. Additionally, the anatomy of perimeniscal structures, particularly those including the meniscocapsular, intermeniscal, meniscofemoral ligaments and other menisco-ligamentous structures is reviewed

CT-guided percutaneous drilling is a safe and reliable method of treating osteoid osteomas

Computed tomography (CT)-guided percutaneous drilling is an alternative for osteoid osteoma treatment. This study aims to evaluate the remodeling of the drill orifice. The success rate and complications were also recorded and compared with other treatment methods. Fifteen patients with an average age of fourteen years (ranging from 4 to 25) submitted to CT-guided percutaneous drilling between 2003 and 2009 were retrospectively analyzed according to clinical and radiological criteria. Fourteen cases showed complete alleviation of pain one week after surgery. No relapse was detected even in the subject who continued complaining of pain. All patients were treated with a day-hospital regimen and were discharged with partial weight bearing. Total weight bearing was allowed after one month, and sports were allowed after consolidation, which occurred in all but one case after the third month. One patient, who did not follow our medical advice, returned to sports activities after two weeks and experienced a fracture as a result. Atrophy of the vastus lateralis muscle developed after the procedure in another patient. Our case series suggests that this method is reliable and safe. The level of complexity is comparable with other minimally invasive percutaneous procedures. The cost is low because there is no need to buy probes or other equipment. The negative points include weakening of the bone and the logistical problem of assembling the orthopedic surgeon, radiologist, and anesthesiologist in the tomography room

Imaging diagnosis in snapping syndromes

A síndrome do estalido ou do ressalto ocorre durante a movimentação de várias articulações e pode ser acompanhada de dor local e de crepitação ou de estalido audível. Nem sempre o estalido audível ou a crepitação articular à palpação têm significado patológico ou implicam necessidade de tratamento. Esta síndrome tem causas variadas intra-articulares e extra-articulares e os achados clínicos podem ser pouco precisos, com dificuldade para definir o melhor método de imagem que confirme o diagnóstico. O objetivo deste trabalho é discutir as causas mais comuns da síndrome do estalido em cada articulação e enfatizar a indicação e a limitação de cada um dos diferentes métodos diagnósticos em situações específicas da prática clínica.Snapping syndromes occur during certain movements in several joints and may be accompanied by local pain and crepitation or audible snapping sensation. Snapping joints may eventually have no pathologic significance and in this case no treatment is required. There is an array of intra- and extra-articular causes of snapping syndrome and the lack of precise clinical findings impairs the definition of the most appropriate imaging method to confirm the diagnosis. The present study is aimed at discussing the most frequent causes of snapping syndrome in different joints, emphasizing the indications and limitations of each of the different diagnostic methods in specific situations of the clinical practice

Use of a large gauge needle for percutaneous sectioning of the Achilles tendon in congenital clubfoot

OBJETIVO: Avaliar a técnica de secção percutânea do tendão calcâneo com a utilização de agulha de grosso calibre para correção do equino residual do pé torto congênito tratado pelo método de Ponseti. MÉTODO: Foram avaliadas prospectivamente 57 secções do tendão calcâneo, em 39 pacientes com pé torto congênito tratados pelo método de Ponseti, no período de julho de 2005 a dezembro de 2008. A tenotomia foi realizada percutaneamente com agulha de grosso calibre. A ultrassonografia foi realizada, em seguida, para avaliar se houve secção tendínea completa e afastamento entre os cotos. RESULTADOS: Houve divisão completa do tendão em todos os casos, porém, foi comum a necessidade de realizar a manobra de secção mais de uma vez, devido à persistência de conexão tendínea residual entre os cotos. O teste de Thompson e a avaliação ultrassonográfica dinâmica foram capazes de evidenciar tenotomias incompletas. A mensuração ultrassonográfica média do afastamento entre os cotos foi de 5,70 ± 2,23 mm. Em dois casos, houve sangramento maior que o habitual, que cessou com compressão local e não comprometeu a perfusão. CONCLUSÃO: A secção percutânea com agulha do tendão calcâneo mostrou-se eficaz e segura para tratamento do equino residual do pé torto tratado pela técnica de Ponseti.OBJECTIVE: To evaluate the percutaneous Achilles tendon sectioning technique using a large gauge needle for the correction of residual equinus of congenital clubfoot treated by the Ponseti method. METHODS: Fifty-seven Achilles tendon sections were prospectively evaluated in thirty-nine patients with clubfoot, treated by the Ponseti method between July 2005 and December 2008. The tenotomy was performed percutaneously with a large gauge needle. Ultrasound scan was performed immediately after the section, to ascertain whether the tenotomy was complete, as well as stump separation. RESULTS: There was complete tendon section in all cases, but the need to perform the section maneuver more than once was common, due to the persistence of the residual strands between tendon stumps. The Thompson test and dynamic ultrasound evaluation were able to detect incomplete tenotomies. The mean ultrasound measurement of the tendon gap was 5.70 ± 2.23 mm. Two patients had abnormal bleeding, which was controlled by digital pressure and did not compromise foot perfusion. CONCLUSION: Percutaneous Achilles tendon sectioning with a needle proved to be efficient and safe to correct residual equinus of clubfoot treated by the Ponseti technique.FINEP - Financiadora de Estudos e Projeto

Complications from the use of intravenous gadolinium-based contrast agents for magnetic resonance imaging

Os agentes de contraste à base de gadolínio são muito mais seguros que o contraste iodado, no entanto, existem complicações que devem ser reconhecidas, para orientação e tratamento adequados. A incidência total de reações adversas aos meios de contraste em ressonância magnética varia entre 2% e 4%. Casos de reações adversas agudas maiores ao gadolínio, como laringoespasmo e choque anafilático, são raros. As complicações crônicas com o uso do gadolínio também existem e, recentemente, foi descrita associação entre seu uso e uma doença dermatológica rara que ocorre em pacientes com insuficiência renal. A fibrose nefrogênica sistêmica foi tema de anúncio público oficial pela agência americana de regulação de drogas, a Food and Drug Administration. Esta doença progressiva caracteriza-se pelo espessamento e endurecimento da pele e fibrose, que podem acometer outras partes do corpo. Os pacientes que desenvolveram esta complicação apresentavam insuficiência renal crônica, estavam em acidose metabólica e foram submetidos a angiografia por ressonância magnética, provavelmente com injeção de grande volume de contraste paramagnético. Esta revisão tem o objetivo de apresentar uma descrição sucinta dos tipos de meios de contraste à base de gadolínio, possíveis complicações e medidas para prevenção e tratamento destas.Gadolinium-based contrast agents are much safer than the iodinated ones; however complications may occur and should be recognized for appropriate orientation and management. The total incidence of adverse reactions to contrast agents in magnetic resonance imaging ranges between 2% and 4%. Cases of severe acute reactions to gadolinium, such as laryngospasm and anaphylactic shock, are rare. Chronic complications secondary to the use of gadolinium also can occur and, recently an association between its use and a rare dermatologic disease occurring in patients with renal failure has been reported. Nephrogenic systemic fibrosis was the subject of an official health notification issued by the American Food and Drug Administration. This progressive disease is characterized by hardened skin with fibrotic nodules and plaques which may involve other parts of the body. Patients who have been affected by this disorder presented chronic renal failure, with metabolic acidosis and had been submitted to magnetic resonance angiography, probably involving exposure to large amounts of intravenous paramagnetic contrast. This review is aimed at presenting a succinct description of the gadolinium-based contrast agent types, possible secondary complications, their preventive measures and management

Intraobserver and interobserver reliability of radial torsion angle measurements by a new and alternative method with computed tomography

OBJECTIVE: To evaluate the intraobserver and interobserver reliability of radial torsion angle measurement using computed tomography. METHODS: Twelve pairs of cadaver radii and 116 forearms from 58 healthy volunteers were evaluated using axial computed tomography sections measured at the level of the bicipital tuberosity and the subchondral region of the radius. During digital imaging, the angle was formed by two lines, one diametrically perpendicular to the radial tubercle and the other tangential to the volar rim of the distal joint surface. Measurements were performed twice each by three observers. RESULTS: In cadaveric bones, the mean radial torsion angle was 1.48º (-6º - 9º) on the right and 1.62º (-6 º - 8º) on the left, with a mean difference between the right and left sides of 1.61º (0º - 8º). In volunteers, the mean radial torsion angle was 3.00° (-17° - 17°) on the right and 2.91° (-16°- 15°) on the left, with a mean difference between the sides of 1.58º (0º - 7º). There was no significant difference between each side. The interobserver correlation coefficient for the cadaver radii measurements was 0.88 (0.72 - 0.96) and 0.81 (0.58 - 0.93) for the right and left radius, respectively, while for the volunteers, the difference was 0.84 (0.77 - 0.90) and 0.83 (0.75 - 0.89), respectively. Intraobserver reliability was high. CONCLUSION: The described method is reproducible and applicable even when the radial tubercle has a rounded contour

A Comparative Analysis between Ultrasonometry and Computer-Aided Tomography to Evaluate Bone Healing

An ultrasonometric and computed-tomographic study of bone healing was undertaken using a model of a transverse mid-shaft osteotomy of sheep tibiae fixed with a semi-flexible external fixator. Fourteen sheep were operated and divided into two groups of seven according to osteotomy type, either regular or by segmental resection. The animals were killed on the 90th postoperative day and the tibiae resected for the in vitro direct contact transverse and axial measurement of ultrasound propagation velocity (UV) followed by quantitative computer-aided tomography (callus density and volume) through the osteotomy site. The intact left tibiae were used for control, being examined in a symmetrical diaphyseal segment. Regular osteotomies healed with a smaller and more mature callus than resection osteotomies. Axial UV was consistently and significantly higher (p?=?0.01) than transverse UV and both transverse and axial UV were significantly higher for the regular than for the segmental resection osteotomy. Transverse UV did not differ significantly between the intact and operated tibiae (p?=?0.20 for regular osteotomy; p?=?0.02 for resection osteotomy), but axial UV was significantly higher for the intact tibiae. Tomographic callus density was significantly higher for the regular than for the resection osteotomy and higher than both for the intact tibiae, presenting a strong positive correlation with UV. Callus volume presented an opposite behavior, with a negative correlation with UV. We conclude that UV is at least as precise as quantitative tomography for providing information about the healing state of both regular and resection osteotomy. (C) 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:10761082, 2012Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (The State of Sao Paulo Research Foundation) [2007/56422-0, 2008/55342-5]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (The State of Sao Paulo Research Foundation

Traumatic atlanto-occipital dislocation: a case report

A luxação traumática atlanto-occipital é lesão rara, de incidência desconhecida e está associada a elevada taxa de mortalidade. Os autores relatam o diagnóstico, tratamento e seguimento de dois anos de uma paciente de 25 anos de idade, vítima de acidente automobilístico e luxação atlanto-occipital traumática confirmada por exames de imagem.Traumatic atlanto-occipital dislocation is a rare lesion whose incidence is not know, and which is associated to a high rate of mortality. The authors report the diagnosis, treatment, and two-year follow-up of a 25 year-old patient who had had an automobile accident with imaging-confirmed traumatic atlanto-occipital dislocation