This retrospective study was conducted, in accordance with the STROBE guidelines, (Vandenbroucke et al., 2007), considering patients receiving surgical interventions for hip and knee replacement at the IRCCS Orthopedic Institute Galeazzi, located in Milan (Italy), between 1 January 2016 and 31 December 2019 (two years of traditional procedure, and two years of new one).

We evaluated 10,922 patients treated for hip or knee joint replacement; there were 5,085 treated following the traditional procedure and 5,837 treated by fast track procedure. Excluding cases which could not satisfy the study criteria we evaluated finally 697 with traditional procedure and 1120 with the new one.

With the new fast track procedure, knee replacement mean costs were decreased by an average of EUR1,112.4 (-19.9%). Excluding the cost of prostheses from the analysis, the mean costs in the pre fast-track period for knee replacement are equal to EUR3,918.1, while the mean cost of the intervention in the fast-track period was equal to EUR3,245.8, being EUR572.3 lower (-17.2%). Considering the number of days of hospitalization, the adoption of fast-track leads to a decrease of -2.8 days (-37.6%) in knee replacement, from a mean number of days of 7.6 (± 2.8), to a mean number of days of 4.8 (± 1.8), and of – 2.9 days (-39.2%) in hip replacement, from a mean number of days of 7.3 (± 2.7) to a mean number of days of 4.4 (± 2.0).

We performed a study over four years, with a wide number of cases treated by various teams in the hospital having the highest workload on hip and knee joint replacements in Italy.

The new fast-track procedure is efficient; the length of stay was decreased by the procedure; the direct and indirect costs were decreased; the hospital organization was improved; the increase of care intensity did not modify efficiency and costs; the effectiveness was similar to the traditional procedure as defined by outcomes collected in a registry, including patient reported outcome measures (PROMs); legal and social effects were not modified.