Fig. 1

These decision curves depict the net benefit of the three-month (a) and 12-month (b) models, when applied to the Italian external validation set. Net benefit is defined as a three- or 12-month survivor who duly undergoes surgery, or receives an implant commensurate with his/her estimated survival. It is important to note that nearly all (93 %) patients referred for orthopaedic intervention survived longer than three months and 63 % survived longer than one year, representing the theoretical maximum net benefit for a and b, respectively. As a result, a indicates that one could achieve better outcomes by assuming all patients will survive greater than 3 months rather than using the three-month model. This analysis highlights the importance of decision analysis, even for relatively accurate models such as this one, with an AUC of 0.80. b indicates that the 12-month model should be used, rather than assume all patients, or none of the patients will survive greater than 12 months