Anatomically-designed bicruciate-retaining total knee arthroplasty demonstrates good two-year survivorship and improvements in patient-reported outcomes: A prospective multicenter single-arm study.

Abstract

To evaluate the early safety and performance of a novel anatomical-design bicruciate-retaining total knee arthroplasty (BCR-TKA) implant (JOURNEY™ II XR; JIIXR) in a prospective multicenter single-arm cohort, with 2-year implant survivorship as the prespecified primary endpoint, and patient-reported outcomes and radiographic findings as secondary exploratory endpoints. Ninety-four patients (106 knees) underwent cemented BCR-TKA with JIIXR at eight centers. The primary endpoint was 2-year survivorship tested for noninferiority versus a 98% benchmark using exact binomial (one-sided 97.5% CI) and Kaplan-Meier methods. Secondary endpoints included the EuroQol 5-Dimension 5-Level (EQ-5D-5L) questionnaire, its visual analogue scale (EQ-VAS), Forgotten Joint Score-12 (FJS-12, collected postoperatively only), Knee Injury and Osteoarthritis Outcome Score (KOOS), range of motion, and radiolucent lines assessed in standardized zones. At 2 years, survivorship was 97.9% (94/96), confirming non-inferiority (<i>p</i> = 0.0064). Patient-reported outcome measures improved over follow-up: EQ-VAS increased from 62.0 preoperatively to 83.7 at 2 years; EQ-5D-5L index from 0.61 to 0.84; and KOOS pain and symptoms from 52.8 and 59.2 to 87.9 and 84.6, respectively. FJS-12 increased from 40.0 at 3 months to 65.4 at 2 years. Across measures, the changes exceeded published minimally clinically important differences (MCIDs): all KOOS subscales met MCID by 1 year, EQ-VAS exceeded MCID by 3 months, and FJS-12 exceeded MCID between 3 months and 1 year. Radiolucent lines were observed in 35 knees (36.5%); total length decreased from 5.1 ± 6.7 mm at 3 months to 2.6 ± 2.3 mm at 2 years with no radiographic loosening. Range of motion at 2 years was similar to baseline. In this prospective single-arm multicenter study, an anatomical-design BCR-TKA implant achieved good 2-year survivorship and clinically meaningful improvements in patient-reported outcomes, with stable radiographic findings. These data support early safety and performance while underscoring the need for long-term comparative studies to establish durability and relative effectiveness. Level II, therapeutic study.