The new OMERACT definitions for the US identification of CPPD proved to be reliable at the level of the HC and FC of the knee. Further studies are needed to better define the US characteristics of CPPD and optimize the scanning technique in other anatomical sites.

Based on the results of our exercise, the OMERACT US definitions for the identification of CPPD demonstrated to be reliable when applied to the TFC and AC. Other sites reached good kappa values in the web-based exercise but failed to achieve good reproducibility at the patient-based exercise, meaning the scanning method must be further refined.

PD positivity in tendons and joints is an independent risk factor of flare in patients with RA in clinical remission. Musculoskeletal ultrasound evaluation is a valuable tool to monitor and help decision making in patients with RA in clinical remission.

US-detected tenosynovitis is a frequent finding in RA patients in clinical remission and associates with unstable remission.

US is potentially a useful tool for the diagnosis of CPPD but universally accepted definitions and further testing are necessary in order to assess the role of the technique in the diagnostic process.