Comparsion of Mobile-bearing UKA and Posterior Cruciate Ligament Retaining TKA for Patients with Unicompartmental Knee Osteoarthritis:a Retrospective Cohort Study

Abstract

Introduction: Many studies have compared unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) for knee osteoarthritis suggesting that both procedures had good clinical outcomes. However, there have been fewer studies comparing the mobile-bearing UKA (MB-UKA) and posterior cruciate ligament retaining TKA (CR-TKA) for patients with unicompartmental knee osteoarthritis. Thus, we explored the differences in outcomes and complications between the two cohorts.Methods: In this retrospective study, 41 patients who underwent MB-UKA and 40 who underwent CR-TKA in our institution were included. All patients were suffered from unicompartmental knee osteoarthritis. Patient demographics, preoperative and latest postoperative range of movement (ROM), Knee Society (KS) scores, and Forgotten Joint Score (FJS) were compared between the two cohorts. Additionally, complications, revisions, and 5-years survivorship were also analyzed.Results: The results showed MB-UKA patients had similar preoperative ROM and Knee Society pain (KSP), functional (KSF), and clinical (KSC) scores with CR-TKA patients (p = 0.104, p = 0.755, p = 0.32, p = 0.928, respectively). The mean follow-up for MB-UKA and CR-TKA groups was 3.4 and 3.7 years, respectively. Two MB-UKA and one CR-TKA patient required revision surgery. The latest postoperative KSF scores, ROM, FJS, and change in KSC scores and ROM were higher (p < 0.05) after MB-UKA, but the latest postoperative KSP, KSC, and change in KSF scores were equivalent between the two cohorts. There were no differences in complication, revision rates, and 5-year survivorship estimates.Conclusions: MB-UKA patients showed better functional outcomes and FJS, and higher ROM with similar survivorship compared with CR-TKA patients. MB-UKA should be considered as a primary treatment option for patients with unicompartmental knee osteoarthritis.Trial registration: researchregistry5032. Registered 23 July 2019, retrospectively registered