Mid-to-long-term outcomes of posterior-stabilized type total knee arthroplasty in asian patients: A single-center retrospective cohort study.

Abstract

Total knee arthroplasty (TKA) is a widely performed orthopedic procedure, yet patient satisfaction remains suboptimal, especially in Asian populations due to implant size mismatches. The FINE total knee prosthesis was anatomically designed for Japanese patients and incorporates medial pivot mechanics. However, mid-to-long-term outcomes of the posterior-stabilized (PS) type remain unreported. We retrospectively analyzed 247 consecutive primary TKAs performed using the PS-type FINE prosthesis at our institution between 2010 and 2017. Patients with at least 5 years of follow-up were included. Clinical outcomes were evaluated using the Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and passive range of motion (ROM). Radiographic assessments included femorotibial angle (FTA), hip-knee-ankle angle (HKAA), and radiolucent line evaluation. Implant survivorship was analyzed using Kaplan-Meier methods. A total of 114 knees (84 patients) met the inclusion criteria with a mean follow-up of 112.2 months. Passive ROM improved significantly (extension from -8.9° to -2.6°, flexion from 121.4° to 124.5°). Favorable improvements in KSS and KOOS were observed. Radiolucent lines ≥2 mm were found in only 4.4 % of tibial zones and none on the femoral side. No revisions were required. Four knees (3.5 %) underwent reoperation for non-mechanical complications. The 10-year reoperation-free survival rate was 95.4 %. The PS-type FINE prosthesis demonstrated excellent mid-to-long-term clinical and radiographic outcomes in Asian patients. Its anatomical design and material properties contribute to its durability and functional success, supporting its use in population-specific TKA strategies.