Background: Involvement of musculoskeletal system in osteoarthritis (OA) includes the presence of arthralgias, deforming arthritis due to cartilage breakdown and formation of osteophytes and soft tissue abnormalities, including bursitis, tendinitis and meniscal lesions. The underlying causes of the clinical presentation of OA are the subchondral bone changes and the presence of synovitis. In a small percentage of patients the degree of synovial inflammation is indistinguishable from an inflammatory condition such as rheumatoid arthritis. Ultrasound technics offer the possibilities for detecting inflammatory changes even in asymptomatic joints or periarticular tissues.
Objective: To perform musculoskeletal ultrasound (MSUS) examination of the symptomatic and asymptomatic joints in patients with OA in regard to its use for defining the disease activity and severity.
Methods: 26 patients with inflammatory OA were included in the study. In all of them ultrasound examination of the joints of upper and lower extremities and the surrounding soft tissues was performed. Detection of inflammation included assessment of parameters as joint effusion (JE), synovial hypertrophy (SH), soft tissue abnormalities (STA) and grading the local pathological vascularization by using power Doppler ultrasound on a semi-quantitative scale from 0 to 3. All patients underwent clinical examination, as well as laboratory measurements: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and microscopic analysis of the synovial fluid for cell count and presence of crystals when possible.
Results: In 8 (30.77%) of the OA patients synovitis was present on MSUS and in 62.50% of them it was scored as grade 1. In 9 (34.62%) patients there was a grade 1 synovial hypertrophy. Osteophytes were present in 7 (26.92%) of the patients. In 5 patients the MSUS detected crystals fixed in the synovium with no history of previous joint injections. SF was withdrawn from 22 patients and on the microscopic examination no crystals were found. There was a correlation between PDUS findings and the laboratory activity of OA, defined by ESR and CRP.
Conclusion: Assessment of symptomatic joints in OA by MSUS including PDUS parameters appears to be a promising sensitive method for detecting and monitoring the inflammatory activity in patients with OA, even in cases of subclinical synovitis.
Keywords: osteoarthritis, musculoskeletal ultrasound, disease activity