Methods. FLS were obtained after enzymatic digestion of synovial tissue (ST) of patients with RA and OA undergoing knee replacement surgery and taken into culture for chemokine receptor analysis by RT–PCR, flow cytometry and functional tests. Immunofluorescence for CCR7, fibroblast and T-cell markers was performed on ST of RA and OA patients. To study the response of FLS to CCR7 ligands and other chemokines, migration assays were performed in modified Boyden chambers. After stimulation of FLS with CCR7 ligands, the secretion of VEGF was evaluated by ELISA and Luminex.

Results. CCR7 is expressed on FLS of patients with RA and OA, but not on dermal fibroblasts. FLS migrated in response to the CCR7 ligands, CCL19 and CCL21. Stimulation of FLS with CCL19 resulted in a significantly increased secretion of VEGF of RA- and OA-FLS.

Conclusion. Apart from the migration of FLS in response to CCL19 and CCL21, it was shown that activation of the CCR7 receptor on FLS results in an enhanced VEGF secretion. A considerable expression of CCR7 ligands in proximity to perivascular infiltrates has previously been described in inflamed synovial tissue of RA patients. Stimulation of FLS via CCR7 could thereby contribute to angiogenesis in the synovial tissue.

Methods. Population-based study of 819 adults aged ≥50 yrs with knee pain. The severity of knee pain and function were measured using the Western Ontario and McMaster Universities scale. Three radiographic views of the knees were obtained.

Results. Seven hundred and seventy-seven participants were eligible (mean age 65.5 yrs, 357 males). Higher ROA severity in each of the tibiofemoral (TF) and patellofemoral (PF) compartments was independently associated with higher mean pain scores (TF: F2, 700 = 9.0, P < 0.0001, PF: F2, 700 = 12.7, P < 0.0001). The same pattern was found for mean function scores (TF: F2, 705 = 7.1, P = 0.001, PF: F2, 705 = 15.9, P < 0.0001). If either the TF or PF compartment was affected by moderate/severe OA, the added presence of OA in the other compartment did not increase the mean pain or function scores.

Conclusions. It is the severity of radiographic disease within a compartment, rather than the distribution of radiographic disease between compartments that is associated with symptoms. ROA in the PF joint is associated with symptoms, emphasizing the importance of radiographic changes in his joint.

Methods. Eleven healthy knees were magnetic resonance (MR) scanned and imaged with a dual fluoroscopic system while the subject performed a weight-bearing single-leg lunge. The tibia, femur and associated articulating cartilage were constructed from the MR images and combined with the dual fluoroscopic images to determine in vivo cartilage contact deformation from full extension to 120° of flexion.

Results. In both compartments, minimum peak compartmental contact deformation occurred at 30° of flexion (24 ± 6% medial, 17 ± 7% lateral) and maximum peak compartmental deformation occurred at 120° of flexion (30 ± 13% medial, 30 ± 10% lateral) during the weight-bearing flexion from full extension to 120°. Average medial contact areas and peak contact deformations were significantly greater than lateral compartment values (P < 0.05). In addition, cartilage thickness in regions of contact was on average 1.4- and 1.1-times thicker than the average thickness of the tibial and femoral cartilage surfaces, respectively (P < 0.05).

Conclusions. These data may provide base-line knowledge for investigating the effects of various knee injuries on joint contact biomechanics and the aetiology of cartilage degeneration.