Relationship between radiographic progression and change of knee extension and flexion angles. A and B. Knee extension angle (A) and flexion angle (B) at baseline and final visit after 36 months (36M) are shown for non-progressed and progressed joints, respectively. Open and solid bars indicate progressed and non-progressed joints, respectively. C and D. Knee extension angle (C) and flexion angle (D) at baseline and final visit after 36 months (36M) are shown for the joints with little increase in osteophyte score (0 or 1) (Unchanged) and those with substantial increase in the score (2 or more) (Increased), respectively. *, P < 0.05, and **, P < 0.01, paired t-test.