Ultrasonography can be used to detect soft tissue abnormalities within the joints that cannot be assessed using conventional X-rays. This study investigated the relationship between soft tissue and/or bony abnormalities on ultrasonography and the biochemical markers of the synovium and cartilage in the knee of osteoarthritis (OA) patients.
The knees from 51 OA patients who fulfilled the ACR criteria were enrolled in this study. Knee ultrasonography was performed in the affected knee joints using a 12 MHz linear probe to assess the presence of effusion, synovial proliferation, capsular distention, the length of osteophytes and the cartilage thickness. At the same time, the serum hyaluronic acid (HA) and the cartilage oligomeric protein (COMP) levels were measured by ELISA, and RIA was used to determine the serum osteocalcin levels.
The patients with a longer medial osteophyte showed higher serum HA and COMP levels than those with a shorter one. The serum HA levels were significantly higher in those patients with a larger amount of effusion and/or synovial proliferation, which indicated inflammatory changes, than in those without. In addition, the severity of the capsular distention also correlated well with the serum HA and COMP levels. However, the length of the lateral osteophytes and the thickness of the femoral cartilage showed no correlation with the serum HA or COMP levels. In addition, the serum osteocalcin levels did not show any association with the above ultrasonographic parameters.
This study demonstrated that the serum HA and COMP levels were elevated in the more severe OA patients by knee ultrasonography than in the less severe patients. This suggests that the detailed pathological changes in the soft tissue and/or bone of the OA joints on ultrasonography are directly reflected by the biochemical markers measured in the peripheral blood.