Returning to running after total knee arthroplasty: a systematic review and a novel multimodal protocol.

Total knee arthroplasty (TKA) is the gold standard for advanced knee osteoarthritis and is increasingly performed on younger, active individuals. While low-impact sports are recommended after TKA, running remains controversial due to concerns about implant loosening. Cemented implants have durability issues at the bone-cement interface, while cementless designs seem to promote better osseointegration. Despite limited research, running after TKA is gaining acceptance. The purpose of this paper is to present a systematic review of the literature and present a novel and specific protocol to guide motivated patients in safely resuming running. We conducted a systematic review of PubMed studies regarding running after TKA and the PRISMA flow diagram shows the inclusion and exclusion criteria adopted. In addition, we present a novel protocol (FAST) specifically designed for TKA patients aiming to return to running which combines surgical techniques, perioperative analgesia, and physical therapy. It has been approved by the Ethics Board, the prospective trial is registered (NCT06383936), and we are currently enrolling participants. After screening according to inclusion and exclusion criteria, six studies were included in the analysis. The FAST protocol combines cementless CR-design implants, minimally invasive surgery, and personalized functional alignment. Local infiltration analgesia reduces pain and enables rehabilitation within 24 h. Rehabilitation progresses with range-of-motion exercises, muscle strengthening, and gradual return to running at 6-8 months. Monitoring activity carefully prevents inflammation, optimizing recovery. Running after TKA, once discouraged, now shows low complication rates. Preoperative fitness and patient-specific factors are key predictors of success. The FAST protocol integrates cementless implants, personalized alignment, and structured rehabilitation. Proper patient selection and communication are essential. Further research is required to validate long-term outcomes.