Objective: To determine the 5-year radiographic progression of osteoarthritis (OA) of the knee in a Czech cohort.
Methods: 139 patients with idiopathic OA were followed for 5 years, receiving only physical therapy and non-steroidal antiinflammatory drugs as needed. Weight-bearing radiographs of both knees were performed at the initial and final evaluation by a single technician using the same instrument and a standardized procedure. Radiographs were evaluated using the Kellgren-Lawrence scale (KL). Joint space width (JSW) was determined by 2 independent trained readers, and discrepancies re-reviewed.
Results: JSW decreased 0.39 +/- 0.95 mm in 5 years, or 0.078 +/- 0.19 annually. The reduction of JSW was greatest in the KL grade III radiographs (0.099 +/- 0.18 mm). The smallest reduction in JSW was seen in those with KL grade I (0.044 +/- 0.14 mm). However, only 25% of those with KL stage II or stage III demonstrated any change in JSW over the 5-year period. The reduction in JSW was not constant, being most rapid in the first year and then much slower. The coefficient of variation (CV) of the method was good (intra- and inter-observer CV 3.6%).
Conclusion: This 5-year follow up of Czech patients with OA of the knee demonstrated a low rate of radiographic progression of JSW. The most rapid progression appeared in KL stage III. The progression was most rapid in the first year.