A CONTINUOUS SERIES OF 969 INDIVIDUALIZED TOTAL KNEE ARTHROPLASTIES WITH MINIMUM TWO-YEAR FOLLOW-UP

Background Individualized Origin® TKA (Symbios, Switzerland) is designed from a CT-scan to reproduce the native alignment, the radii of curvature, the trochlear orientation and to optimize the bone-implant fit. Material and methods From December 2018 (CE mark) to December 2023, 969 cemented Origin-TKA (814 PS, 146 CR) were implanted: 879 unilateral, 90 bilateral, 626 in females, 504 in right knees. Mean height was 166 cm (145 to 195), weight was 77kg (45 to 180) and age was 72y (46 to 94). The patella was resurfaced in 666 knees. Indication was OA (680 medial, 191 lateral, 51 patellofemoral, 37global), Osteonecrosis (6) and RA (4). Bone cuts were done with PSI, and medio-lateral laxity was then evaluated with the trials: 49% were well-balanced, 35% required a tibial recut of 1 or 2mm, 8% required a varus/valgus tibial recut of 1 or 2° and 8% a +2mm PE. Patients were followed at 1 year and every two years. Patients completed pre- and post-operative PROMs: OKS, FJS and WOMAC as well as overall level of satisfaction. Proportions that attained a patient acceptable symptom state (PASS) were calculated for patients operated in 2019 (n= 153, mean FU = 33 months) Results At FU three prosthesis were revised: one loosening, one periprosthetic fracture, one chronic infection (KM survivorship = 99.6% (98.9 to 100)). Three secondary patellar resurfacing and three D.A.I.R. for early infection were performed (KM survivorship = 97.7% (97.7 to 99.7). 94.4% were either satisfied or very satisfied with their TKA. The mean OKS was 39.6 ± 7.6, FJS was 69.0 ± 27.7. Proportions that achieved PASS were 89% for OKS, and 85% for FJS. Conclusion This series demonstrates the feasibility of Individualized TKA on a large series. However, methods to predict the soft-tissue behavior of a given patient are still to be found.