Fig. 2

ROC curves depicting Absolute (top row) and Relative (bottom row) improvement in 6MWT distance (black line) and 95 % CI of specificity (grey shading) at 26-weeks post-operative. Panels a and d depict the slight or more important difference b and e depict moderate or more important and c and f depict much better important difference. DeLong’s test compares AUC of graph to that of the minimal important difference