Approach to a patient with monoarticular disease

Purpose: To reassess the diagnostic approach to a patient with a monoarticular disease in light of the up-to-date medical literature and to examine the practical utility of traditional and newer imaging tools in the setting of monoarthritis. Results: The monoarticular disease can represent a medical emergency on the one hand and be a diagnostic conundrum on the other. The management rules of patients with monoarthritis have been established long ago, but various pitfalls still lead physicians off the right diagnosis at times. Septic, pseudoseptic arthritis and hemarthrosis are the most common diagnoses made in patients with an acute presentation, and a decision not to perform a diagnostic arthrocentesis is the most prevalent cause of misdiagnosis in this setting. Many rheumatic and infectious diseases can present with more indolent monoarthritis; careful history and physical examination frequently provide clues to the straightforward diagnosis in some cases, but the extensive investigation is needed in others. Imaging methods become indispensable in individuals with the non-inflammatory monoarticular disease, with magnetic resonance imaging being the gold standard for diagnosing pigmented villonodular synovitis, lipoma arborescence, avascular necrosis, or neuropathic arthropathy. Conclusions: A great variety of medical disorders can present as a monoarticular disease. The disease presentation dictates different diagnostic behavior, while knowing the available imaging methods' diagnostic potential should further shorten the diagnostic process.