Periprosthetic soft tissue recurrence of chondroblastoma after attempted en bloc excision from the proximal humerus

A case of soft tissue recurrence of chondroblastoma after attempted en bloc excision and endoprosthetic replacement is described. This tumor in the proximal humerus recurred after initial curettage and was subsequently treated by attempted en bloc excision with positive microscopic margins. The patient then presented with a large soft tissue recurrence surrounding the endoprosthesis. This periprosthetic recurrence necessitated re-excision and revision of the endoprosthesis. Recurrence is not uncommon following curettage of chondroblastoma. However, less is known about soft tissue recurrence after en bloc resection of this tumor with positive margins. A subset of chondroblastoma may exist with more locally aggressive behavior.     

Partial Hawkins sign in fractures of the talus: a report of three cases

OBJECTIVE: We introduce the concept of the partial Hawkins sign in three cases of talar neck fracture that are associated with incomplete avascular necrosis. Our objective is to call attention to the intraosseous blood supply of the talar body, which can be interrupted by fractures to produce patterns of incomplete avascular necrosis. CONCLUSION: We conclude that the Hawkins sign does not always have to be complete. Fractures of the talus occasionally can lead to partial avascular necrosis because of the disruption of end arteries within the body of the talus, even without subluxation or dislocation. Early recognition of the partial Hawkins sign should lead to MRI evaluation that can more readily define the involvement of the talar body and assist the treating physician in recommending when the patient can bear weight.     

Kv1.3 channels are a therapeutic target for T cell-mediated autoimmune diseases

Autoreactive memory T lymphocytes are implicated in the pathogenesis of autoimmune diseases. Here we demonstrate that disease-associated autoreactive T cells from patients with type-1 diabetes mellitus or rheumatoid arthritis (RA) are mainly CD4+ CCR7- CD45RA- effector memory T cells (T(EM) cells) with elevated Kv1.3 potassium channel expression. In contrast, T cells with other antigen specificities from these patients, or autoreactive T cells from healthy individuals and disease controls, express low levels of Kv1.3 and are predominantly na?ve or central-memory (T(CM)) cells. In T(EM) cells, Kv1.3 traffics to the immunological synapse during antigen presentation where it colocalizes with Kvbeta2, SAP97, ZIP, p56(lck), and CD4. Although Kv1.3 inhibitors [ShK(L5)-amide (SL5) and PAP1] do not prevent immunological synapse formation, they suppress Ca2+-signaling, cytokine production, and proliferation of autoantigen-specific T(EM) cells at pharmacologically relevant concentrations while sparing other classes of T cells. Kv1.3 inhibitors ameliorate pristane-induced arthritis in rats and reduce the incidence of experimental autoimmune diabetes in diabetes-prone (DP-BB/W) rats. Repeated dosing with Kv1.3 inhibitors in rats has not revealed systemic toxicity. Further development of Kv1.3 blockers for autoimmune disease therapy is warranted.     

Cartilage metabolism in osteoarthritis and the influence of viscosupplementation and steroid: a review

Osteoarthritis (O.A.) is the most common type of articular disease. This is an idiopathic joint disease characterized by an imbalance between synthesis and degradation of articular cartilage and subchondral bone accompanied by capsular fibrosis, osteophyte formation and variable grade of inflammation of synovial membrane. Joint lubrication is naturally provided by Hyaluronic acid in syovial fluid. Hyaluronan is present in abundance in normal young and healthy joints. In degenerative O.A. Hyaluronan is smaller in size, molecular weight and diminished in concentration. This decrease in joint lubrication and shock absorbing mechanism in O.A. can be remedied by intraarticular viscosupplementation. Alternatively the pain and secondary inflammation in O.A. can be relieved by intraarticular injection of steroids and long acting local anesthetics. Promt and effective reduction in local inflammation occurs after intra-articular injection of corticosteriod. This article reviews the cartilage metabolism in O.A., discusses the pros and cons of these treatments and provides a literature review of the studies which compare benefits and adverse reactions of viscosupplementation vs. intraarticular steroids with placebo treatment.     

Paget's disease of bone: review with emphasis on radiologic features,part II

Part I discusses the correlation between the clinical, radiologic and histologic features with the three phases (incipient, mid- and late phase) of Paget's disease. In this section, we will discuss in detail the radiologic features by location as well as aberrant radiographic presentations in addition to secondary tumors such as post radiation sarcomas and giant cell tumors which occur in Paget bone. Because Paget's disease generally affects people in their middle and late ages, the differential diagnosis often includes metastatic disease and the differentiation can often be quite challenging. Moreover, metastatic disease to bones afflicted with Paget's disease can further add diagnostic confusion. These critical aspects will be discussed in this section of Paget's disease of bone.     

Scaphoid fracture: evaluation with flexion-extension tomography

Assessment of healing of a scaphoid fracture, which may be associated with delayed fusion and nonunion, is a challenging task for the radiologist. Thirty cases of clinically suspected nonunion scaphoid waist fractures with inconclusive plain radiographs were prospectively studied by means of stationary tomography and lateral flexion-extension tomography. The angle between the two scaphoid fragments as seen in extension was measured and compared with the angle as seen in flexion. A difference of 10 degrees or greater between flexion and extension was considered significant. This was noted in 14 of 15 cases of nonunion. Fifteen cases without angle differences were accurately diagnosed as stable. One false-negative case was noted, which on review was attributed to a limited extension view. Flexion-extension tomography is a highly valuable diagnostic modality in evaluating the stability and healing of scaphoid fracture and is superior to conventional (stationary) tomography.     

Radiographically ossified ganglion cyst of finger in a swimmer

Ganglion cysts are fibrous-walled cystic lesions closely associated with joint or tendon sheaths and contain gelatinous mucinous fluid. The radiographic appearance is usually normal. Calcification or ossification in these cysts is extremely unusual. We report on an unusual appearing ganglion cyst of the little finger in a swimmer with ossification resembling myositis ossificans.     

Diagnostic uses of nuclear medicine in AIDS.

Radionuclide imaging, if applied with an organ system approach, is useful in the diagnosis of the AIDS (acquired immunodeficiency syndrome)-related complex. Specific pathologic processes can be suspected on the basis of uptake patterns. The intensity and pattern of pulmonary uptake and concomitant nonpulmonary uptake of gallium provide guidelines for distinguishing among various opportunistic pulmonary pathogens. Gastrointestinal and extra-gastrointestinal tract uptake of gallium aids distinction among fungal, mycobacterial, and viral infections and neoplasms. Patterns of spleen uptake of technetium-99m sulfur colloid and gallium allow differentiation between neoplasm (Kaposi sarcoma) and infection (with mycobacteria). Skeletal and soft-tissue abnormalities can be characterized and differentiated on the basis of bone scan and other radionuclide scan findings. Thallium uptake in brain tumors (and not in areas of infection) allows brain lesion discrimination. In the proper clinical setting, AIDS nephropathy has a characteristic gallium uptake pattern. Cardiac abnormalities (including functional) can also be assessed with scintigraphy. With knowledge of these organ-specific patterns and with correlative imaging studies, the manifestations of AIDS can be differentiated and appropriate treatment instituted.