Ultrasound of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) finger joint cartilage can effectively discriminate osteoarthritis from early rheumatoid arthritis (RA), Swiss researchers report.
“Loss of cartilage reflects irreversible joint destruction and contributes to impaired joint function in osteoarthritis and RA,” note Burkhard Möller (University of Berne) and colleagues.
They add that cartilage loss is generally assessed radiographically but ultrasound may be a preferable alternative because it allows simultaneous evaluation of cartilage and synovitis from a single examination without the use of ionizing radiation.
In the present study, Möller and team evaluated the reliability and validity of ultrasound imaging to measure MCP and PIP finger joint cartilage in 48 patients with RA, 18 patients with osteoarthritis, 24 patients with unclassified arthritis of the finger joints, and 34 healthy controls.
Each study participant underwent ultrasound scanning to visualize the proximal cartilage layer of MCP and PIP joints from a posterior view in the second to fifth fingers, with joints in a 90-degree flexed position.
The researchers were able to accurately measure cartilage thickness, using integrated tools, in 97.5% of MCP and 94.2% of PIP joints.
The total joint score was highest in the control group and lowest in patients with osteoarthritis. Patients with recent-onset synovitis with osteoarthritis had significantly lower ultrasound scores than those with early RA. In contrast, there was no significant median difference between healthy controls and patients with early RA.
The ability of ultrasound to discriminate patients with osteoarthritis from those with early RA and healthy volunteers was tested using receiver operating characteristic analysis, which gave an area under the curve of 0.89 for the total joint score.
Möller et al report good inter- and intraobserver reliability for the ultrasound method as well as a good correlation with the joint space narrowing score for both hands and the joint space width of the same finger joints measured from conventional radiographs.
“The ultrasound method of direct visualization and quantification of cartilage in MCP and PIP joints is objective, reliable, valid, and can be useful for diagnostic purposes in patients with arthritis,” the authors conclude in the journal Arthritis Care and Research.
anyone have this done yet?