Mid-term results show no significant difference in postoperative clinical outcome, pain and range of motion between a well-established total knee arthroplasty design and its successor: a prospective, randomized, controlled trial

PURPOSE: The purpose of this study was to compare the clinical and functional outcome scores following total knee arthroplasty (TKA) with two different systems. The hypothesis was that there is a difference between patients receiving the newer design than those receiving the predecessor. METHODS: Two hundred patients who underwent TKA were randomized into two groups: patients received either Attune TKA or PFC Sigma (both DePuy Synthes, Warsaw, IN). Clinically, the Knee Society Knee and Function Scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Range of Motion (ROM) and Visual Analogue Scale (VAS) were evaluated and compared between the groups 2 years after surgery. 158 patients (80 in the Attune group and 78 in the PFC Sigma group) were available for follow-up. RESULTS: Through bivariate analysis using parametric and non-parametric statistical tests, no significant differences in postoperative KS, FS, WOMAC, ROM or VAS between the two groups were detected. Both groups significantly improved regarding all evaluated endpoints 2 years after surgery. CONCLUSIONS: In the current study population, no difference in clinical outcome between the two systems was found. The expected benefits of design modifications could not be observed in clinical outcome scores 2 years postoperatively. Both designs are effective options for improving pain and function in end-stage osteoarthritis. LEVEL OF EVIDENCE: I.