DOS 2019

176 · DOS Abstracts Patient-reported results are the same across Danish high-volume knee arthroplasty centers despite persistent differences in revision rates Anne Mørup-Petersen, Mogens Laursen, Frank Madsen, Michael R. Krogsgaard, Matilde Winther-Jensen, Anders Odgaard Department of Orthopaedic Surgery, Herlev and Gentofte Hospital; Department of Orthopaedic Surgery, Aalborg University Hospital, Farsoe; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Section for Sports Traumatology, Bispebjerg and Frederiksberg Hospitals; Center for Clinical Research and Prevention, Department of Clinical Epidemiology, Bispebjerg and Frederiksberg Hospitals Background: The SPARK study was initiated to explore whether the persistent differ- ences in revisions rates after primary knee replacement across Danish regions were a sign of varying surgical quality. Our hypothesis was that patient-reported outcome measures (PROMs) could offer new aspects to the debate. So far, we have documented no varia- tion in preoperative symptoms but some variations in patient selection between regions. Purpose / Aim of Study: This study compares 1-year results after primary knee re- placement in three centers traditionally known to differ in revision rates. Materials and Methods: In a prospective cohort study of 1452 patients undergoing primary knee arthroplasty of any kind in Aarhus (n=321), Farsoe (202) or Gentofte (929), PROM sets were emailed pre- and postoperatively (6 weeks, 3, 6 and 12 months). Main outcome was Oxford Knee Score (OKS) at 1 year; secondary outcomes were pa- tient satisfaction, EQ-5D, UCLA Activity Scale, Forgotten Joint Score, global knee rating (0- 100) and Copenhagen Knee ROM Scale. Findings / Results: Within the first year, 32 patients were excluded due to revision: 22 in Gentofte (2.4%) 2 in Aarhus (0.6%) and 4 in Farsoe (2.0%). One-year answers were provided by 1307 patients (90% of all, or 93% of contacted patients). Overall OKS at 1 y. was 39.0 (SD 7.4) with no significant regional difference (P=0.092). Mean change in OKS was 15.4 (8.1). In Aarhus, it was lower but when adjusted age, sex and preoperative value, this was insignificant. Assigning imputed low OKS-values to revised (excluded) patients revealed no regional difference either. Patients were equally willing to repeat surgery (92%, P=0.124) and equally satisfied across regions (86%, P=0.642). A small, yet significant difference in knee extension was noted in Aarhus, where unicompartmen- tal implants were used more frequently. Conclusions: Despite well-known differences in revision rates, we found no differ- ences in surgical quality between Danish high-volume knee replacement centers from a patients’ perspective. Our study outlines that traditional registers, however well they contribute to the surveillance of joint replacement, cannot stand alone in the evaluation of surgery. Further studies should explore regional variations in thresholds for revision. 132.