Primary synovial chondromatosis represents an uncommon benign neoplastic process with hyaline cartilage nodules in the subsynovial tissue of a joint, tendon sheath, or bursa. The nodules may enlarge and detach from the synovium. The knee, followed by the hip, in male adults are the most commonly involved sites and patient population. The pathologic appearance may simulate chondrosarcoma because of significant histologic atypia, and radiologic correlation to localize the process as synovially based is vital for correct diagnosis. Radiologic findings are frequently pathognomonic. Radiographs reveal multiple intraarticular calcifications (70%-95% of cases) of similar size and shape, distributed throughout the joint, with typical "ring-and-arc" chondroid mineralization. Extrinsic erosion of bone is seen in 20%-50% of cases. Computed tomography (CT) optimally depicts the calcified intraarticular fragments and extrinsic bone erosion. Magnetic resonance (MR) imaging findings are more variable, depending on the degree of mineralization, although the most common pattern (77% of cases) reveals low to intermediate signal intensity with T1-weighting and very high signal intensity with T2-weighting with hypointense calcifications. These signal intensity characteristics on MR images and low attenuation of the nonmineralized regions on CT scans reflect the high water content of the cartilaginous lesions. CT and MR imaging depict the extent of the synovial disease (particularly surrounding soft-tissue involvement) and lobular growth. Secondary synovial chondromatosis can be distinguished from primary disease both radiologically (underlying articular disease and fewer chondral bodies of variable size and shape) and pathologically (concentric rings of growth). Treatment of primary disease is surgical synovectomy with removal of chondral fragments; recurrence rates range from 3% to 23%. Malignant transformation to chondrosarcoma is unusual (5% of cases) and, although difficult to distinguish from benign disease, is suggested by multiple recurrences and marrow invasion. Recognizing the appearances of primary synovial chondromatosis, which reflect their underlying pathologic characteristics, improves radiologic assessment and is important to optimize patient management.
Incidental enchondromas can be identified on 2.9% of routine MR knee examinations, most frequently in the distal femur (2.0%). This significant prevalence is much higher than in an autopsy series (0.2%), likely reflecting the increased sensitivity of MRI for detecting small lesions, and is important to recognize to avoid confusion with other pathologic entities.
As the largest tarsal bone and the most inferior bone in the body, the calcaneus is responsible for supporting the axial load from the weight of the body. It is most commonly fractured after a fall from a height in which axial loads exceed its support capacity. Calcaneal fractures account for 60% of all tarsal fractures. Conventional radiography is commonly used for initial evaluation of calcaneal injury but has the typical disadvantages of two-dimensional imaging. Modern assessment of calcaneal fractures relies heavily on multidetector computed tomography (CT), which allows better visualization and characterization of fracture lines and fragment displacement. Calcaneal fractures observed at CT have been divided into intra- and extraarticular fractures on the basis of subtalar joint involvement. The Sanders classification system for intraarticular fractures is the most commonly used system because it correlates with clinical outcomes and involves less interobserver variability. The classification of extraarticular fractures has been less controversial and makes use of anatomic landmarks on the calcaneus to divide the bone into anterior, middle, and posterior areas. Soft-tissue involvement is an important aspect of calcaneal fracture assessment because it has been linked with poor functional outcomes. Familiarity with the normal anatomy of the calcaneus, the classification of calcaneal fractures, and the various complications of these fractures is essential for treatment assessment, especially if surgical intervention is required.
Kienböck disease is a condition marked by avascular necrosis of the lunate bone. MRI is useful in diagnosis and staging and should be considered, after conventional radiography, for patients with suspected Kienböck disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.