Figure 7

(a) Change over time in ultrasound signal intensity (an index of stiffness) of the plug site (open circles) and the sham side (closed circles). Intensity is represented as relative values. Repeated measures analysis of variance and post-hoc test (Scheffe's F-test) revealed that the signal intensity of the two sides differed significantly at 8 weeks (* P < 0.05) and that the signal intensity of the grafted side differed significantly among the groups (P values are presented in Table 2). Especially between day 0 (D0) and week 2 (2 W) and between weeks 4 (4 W) and 8 (8 W), the values differed significantly (** P < 0.001), but there was no difference between 2 W and 4 W or among the groups 8 W, 12 W and week 24 (24 W). (b) Change over time in signal duration (an index of surface irregularity) of the plug site and the sham side. Values are presented as μs. Signal duration of the two sides differed significantly at 2 W and 8 W (* P < 0.05). (c) Changes over time in interval between signals (an index of thickness) of the plug site and the sham side. Values are represented as μs. Values on both sides were the same (0.5 μs) at D0. After 2–8 weeks postoperatively, the values almost paralleled each other and the difference between them was 0.1 or 0.2 μs. At 12 weeks the difference increased to 0.3 μs, but by 24 weeks postoperatively no difference was observed, at which time the value for both sides was 0.6 μs.