IntroductionFast-track protocols (FP) are used more and more to optimize results after total knee arthroplasty (TKA). Many studies evaluating FP in TKA concentrate on clinical outcome and medium to long-term results. Since discharge from hospital after TKA is achieved increasingly quicker worldwide using FP in an increasingly younger and active patient population, the effects of FP on functional outcome in the first days after TKA become more important. The purpose of the current study was to compare FP with a regular joint care protocol (RP), with an emphasis on the first 7Â days after surgery.Materials and methodsA non-blinded randomized controlled clinical pilot study was performed with 25 patients assigned to a FP group and 25 patients assigned to a RP group. Primary outcome was functional outcome, clinical outcome, pain, and complications for each day in the first week after surgery. Patients were followed up to 5Â years after surgery.ResultsSignificantly lower VAS scores for knee pain, faster Timed-Up and Go test times and more mobility on functional tests were seen on several days in the first week in the FP group compared to the RP group. Few other significant differences were found at 2, 6Â weeks, and no significant differences were found at 12Â weeks and 1, 2 and 5Â years after surgery.ConclusionsFast-track protocol for primary TKA showed significantly lower knee pain scores and improved functional outcome in the first 7Â days after TKA compared to a regular protocol.