Ultrasound in osteoarthritis and crystal-related arthropathies

Abstract

Ultrasonography (US) is a safe and cheap imaging technique which in experienced hands allows for a multiplanar and multisite high-resolution assessment of both morphological and structural features of bone, cartilage, and intra- or periarticular soft tissues. This chapter describes the main applications of US in patients with osteoarthritis (OA) and crystal-related arthropathies. Imaging plays a key role for diagnosis, prognosis, and follow-up in patients with OA. Although conventional radiography is still the gold standard imaging technique in daily clinical practice, US has been revealed to be capable of detecting a wide spectrum of otherwise undetectable details, including cartilage damage, joint effusion, synovial hypertrophy, osteophyte formation, and meniscal protrusion. Crystal visualization by US has the potential to change the diagnostic approach in patients with suspicion of crystal-related arthropathies. The double-contour sign, due to urate crystal deposits on the chondrosynovial interface of the hyaline cartilage, is a highly specific finding for gout as well as the hyperechoic spots within the hyaline cartilage for calcium pyrophosphate dihydrate crystal deposition disease. The potential applications of US in the management of patients with OA and crystal-related arthropathies are not only limited to diagnosis and monitoring. Finally, US guidance allows the real-time visualization of the needle moving through different tissues and reaching the target to aspirate and/or inject. The correct placement of the tip of the needle plays a key role in improving efficacy and reducing side effects of the injection.