Fig. 2.

This decision tree represents the four possible scenarios stemming from the use of the 12-month models. Each outcome, a, b, c, or d, corresponds to a theoretical clinical scenario. For instance, true positives are those that result in the appropriate use of durable implants, false positives are those in which more durable implant are used unnecessarily (when less durable implants would have sufficed), false negatives are those in which less durable implants were used when more durable implants were required, and true negatives are those in which appropriate less durable implants were used.