Dakshesh B. Patel

Giant Cell Tumor of Bone: Review, Mimics, and New Developments in Treatment

Giant cell tumor (GCT) of bone is generally a benign tumor composed of mononuclear stromal cells and characteristic multinucleated giant cells that exhibit osteoclastic activity. It usually develops in long bones but can occur in unusual locations. The typical appearance is a lytic lesion with a well-defined but nonsclerotic margin that is eccentric in location, extends near the articular surface, and occurs in patients with closed physes. However, GCT may have aggressive features, including cortical expansion or destruction with a soft-tissue component. Fluid-fluid levels, consistent with secondary formation of aneurysmal bone cysts, are seen in 14% of cases. GCT can mimic or be mimicked by other benign or malignant lesions at both radiologic evaluation and histologic analysis. Rarely, GCT is associated with histologically benign lung metastases or undergoes malignant degeneration. In the past, the mainstay of treatment was surgical, primarily consisting of curettage with cement placement, with recurrence rates of 15%-25%. Recurrence is suggested by development of progressive lucency at the cement-bone interface. Other complications include pathologic fracture and postoperative infection. Denosumab, a monoclonal antibody that targets the osteoclastic activity of GCT, has produced 90% tumor necrosis in early studies, results indicative of promise as a potential adjuvant therapy.

Sclerosing Bone Dysplasias: Review and Differentiation from Other Causes of Osteosclerosis

Sclerosing bone dysplasias are skeletal abnormalities of varying severity with a wide range of radiologic, clinical, and genetic features. Hereditary sclerosing bone dysplasias result from some disturbance in the pathways involved in osteoblast or osteoclast regulation, leading to abnormal accumulation of bone. Several genes have been discovered that, when disrupted, result in specific types of hereditary sclerosing bone dysplasia (osteopetrosis, pyknodysostosis, osteopoikilosis, osteopathia striata, progressive diaphyseal dysplasia, hereditary multiple diaphyseal sclerosis, hyperostosis corticalis generalisata), many of which exhibit similar pathologic mechanisms involving endochondral or intramembranous ossification and some of which share similar underlying genetic defects. Nonhereditary dysplasias include intramedullary osteosclerosis, melorheostosis, and overlap syndromes, whereas acquired syndromes with increased bone density, which may simulate sclerosing bone dysplasias, include osteoblastic metastases, Paget disease of bone, Erdheim-Chester disease, myelofibrosis, and sickle cell disease. Knowledge of the radiologic appearances, distribution, and associated clinical findings of hereditary and nonhereditary sclerosing bone dysplasias and acquired syndromes with increased bone density is crucial for accurate diagnosis.

The Morel-Lavallée lesion: pathophysiology, clinical presentation, imaging features, and treatment options

Morel-Lavallée lesions are posttraumatic hemolymphatic collections related to shearing injury and disruption of interfascial planes between subcutaneous soft tissue and muscle. We review the pathophysiology of Morel-Lavallée lesions, clinical presentation, and potential sites of involvement. Magnetic resonance imaging (MRI) is the modality of choice for characterization. We present the MRI classification and highlight the key imaging features that distinguish the different types, focusing on the three most common: seroma, subacute hematoma, and chronic organizing hematoma. Potential mimics of Morel-Lavallée lesions, such as soft tissue sarcoma and hemorrhagic prepatellar bursitis, are compared and contrasted. Treatment options and a management algorithm are also briefly discussed.

Cruciate ligament avulsion fractures: Anatomy, biomechanics, injury patterns, and approach to management

Injury to the ACL or PCL of the knee most commonly involves a tear of the collagenous fibers of the ligament. Less frequently, a cruciate ligament injury involves an avulsion fracture at the origin or insertion of the ligament, usually from the insertion site on the tibial surface. Avulsion fractures of the cruciate ligaments are important, as they can be identified on radiographs, allowing a specific diagnosis. Although more common in children, when they occur in adults, they are more commonly associated with other injuries. The treatment of cruciate ligament avulsion fractures is different than the treatment of intrasubstance tears of the cruciate ligaments. These injuries can be treated conservatively or surgically with good outcomes. Recently arthroscopic fixation of these injuries with various fixation devices has become more frequent. Treatment largely depends on the type of fracture, particularly, the size, displacement, comminution, and orientation of the avulsed fracture fragment, in addition to the integrity of the attached cruciate ligament. This review article covers the anatomy and biomechanics of the cruciate ligaments, their injury patterns, and approach to management.

Transient lateral patellar dislocation: review of imaging findings, patellofemoral anatomy, and treatment options

Transient patellar dislocation is a common sports-related injury in young adults. Although patients often present to the emergency department with acute knee pain and hemarthrosis, spontaneous reduction frequently occurs, and half of cases are unsuspected clinically. Characteristic magnetic resonance imaging (MRI) findings often lead to the diagnosis. The purpose of this review is to illustrate the MRI findings of lateral patellar dislocation and concomitant injuries, such as kissing contusions of the medial patella and lateral femoral condyle; osteochondral and avulsion fractures; and injuries of the medial patellofemoral ligament/retinacular complex. This article will also briefly review patellofemoral anatomy and passive, active, and static stabilizers. Predisposing factors for patellar instability, including trochlear dysplasia, patella alta, and lateralization of the patella or tibial tuberosity and their relevant measurements will also be highlighted. Treatment options, including surgery, such as medial patellofemoral ligament reconstruction, tibial tuberosity transfer, and trochleoplasty, and their postoperative imaging appearances will also be discussed.

Structure and function, injury, pathology, and treatment of the medial collateral ligament of the knee.

The medial collateral ligament (MCL) is the most commonly injured ligament of the knee. There is a spectrum of injury severity, and injuries may be acute or chronic. The MCL is also frequently injured in conjunction with other knee structures. Clinical evaluation of the knee is important to assess the degree of surgical acuity, but magnetic resonance imaging can provide details about the injury that may not be obvious clinically. In addition to injury, MCL bursitis can occur and may be treated with needle aspiration and corticosteroid injection. This review article covers the anatomy and biomechanics of the MCL, its injury patterns and approach to management, and MCL bursitis.

Acromioclavicular joint injuries and reconstructions: a review of expected imaging findings and potential complications

Shoulder injuries, including acromioclavicular (AC) joint separations, remain a common reason for presentation to the emergency room. Although the diagnosis can be made apparent through proper history and physical examination by the emergency medicine physician, ascertaining the degree of injury can be difficult on the basis of clinical evaluation alone. While there is consensus in the literature that low-grade AC joint injuries can be treated with conservative management, high-grade injuries will generally require surgical intervention. Furthermore, the treatment of grade 3 injuries remains controversial, making it incumbent upon the radiologist to become comfortable with distinguishing this diagnosis from lower or higher grade injuries. Imaging of AC joint injuries after clinical evaluation is generally initiated in the emergency room setting with plain film radiography; however, on occasion, an alternative modality may be presented to the emergency room radiologist for interpretation. As such, it remains important to be familiar with the appearance of AC joint separations on a variety of modalities. Another possible patient presentation in both the emergent and nonemergent setting includes new onset of pain or instability in the postsurgical shoulder. In this scenario, the onus is often placed on the radiologist to determine whether the pain or instability represents the sequelae of reinjury versus a complication of surgery. The purpose of this review is to present an anatomically based discussion of imaging findings associated with AC joint separations as seen on multiple modalities, as well as to describe and elucidate a variety of potential complications which may present to the emergency room radiologist.

Madura foot: two case reports, review of the literature, and new developments with clinical correlation

Abstract“Madura foot” or pedal mycetoma is a rare destructive infection of the skin and subcutaneous tissues of the foot, progressing to involve muscle and bone. The infection can be caused by both bacteria and fungi. Infection typically follows traumatic implantation of bacteria or fungal spores, which are present in soil or on plant material. Clinically, this entity can be difficult to diagnose and can have an indolent and progressive course. Early diagnosis is important to prevent patient morbidity and mortality. We present two cases of pedal mycetoma, review the literature, review new developments in diagnosis, and discuss magnetic resonance imaging (MRI) features of this unusual entity.

Hand Infections: Anatomy, Types and Spread of Infection, Imaging Findings, and Treatment Options

Infections of the hand are common, particularly in immunocompromised patients, and can lead to significant morbidity, including amputation, if not treated properly. Hand infection can spread far and wide from the original site of inoculation through interconnections between the synovium-lined and nonsynovial potential spaces. Because surgery is the mainstay of treatment, knowledge of the pertinent anatomy is imperative for accurately describing the presence, location, and extent of infection. The authors review the pertinent anatomy of the spaces of the hand and describe different types of infection-including cellulitis, necrotizing fasciitis, paronychia, felon, pyogenic flexor tenosynovitis, deep space infections, septic arthritis, and osteomyelitis-and common causative organisms of these infections. They also describe various modes of spread; the common radiologic appearances of hand infections, with emphasis on findings at magnetic resonance imaging and ultrasonography; and the role of radiology in the management of these infections, along with a brief overview of treatment options.

Lipoma arborescens of the biceps tendon sheath

Lipoma arborescens, described as lipomatous infiltration and distention of synovial villi resulting in a frond-like appearance, most frequently affects the suprapatellar recess of the knee. While there have been reports of this entity involving the upper extremity joints, bursa, and tendon sheaths, we present the first reported case of lipoma arborescens isolated to the biceps tendon sheath. We describe imaging and histologic findings with clinical correlation.