Introduction: Compared to total knee arthroplasty (TKA), mobile-bearing unicompartmental knee arthroplasty (UKA) is associated with better outcomes, such as an earlier recovery, less postoperative pain, lower morbidity and mortality, and a greater "feel" of a normal knee. However, no study has reported the clinical outcomes in patients with the same stage of osteoarthritis of the knee. The purpose of this study was to determine the clinical outcomes, including the Joint Forgotten Score (JFS), Oxford Knee Score (OKS), Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Kujala score after UKA on one knee and TKA on the opposite knee in the same patient.
Materials and methods: We retrospectively reviewed 32 patients with anteromedial OA who underwent mobile-bearing UKA in one knee and TKA in the other knee from 2009 to 2017. The JFS, OKS, KSS, KOOS, and Kujala scores were recorded and compared between the groups. Patients' preferences between UKA and TKA and satisfaction were also recorded.
Results: The JFS and KOOS in the UKA group were significantly (p = 0.01, 0.01) higher than those in the TKA group: 97.01 ± 3.26 (89.58-100) vs. 94.92 ± 3.34 (87.80-100) and 91.16 ± 2.67 (85.25-96) vs. 89.24 ± 2.67 (84.50-94.71), respectively. The OKS, KSS, and Kujala scores were not different between the two groups (p = 0.82, 0.95, and 0.31, respectively) and neither was patient preference (p = 0.41) or satisfaction (p = 0.42). The mean follow-up was 48.36 months (range 24.00-96.00 months), during which there were no postoperative complications.
Conclusion: UKA was associated with a better JFS and KOOS but was otherwise comparable to TKA and may be preferable.
Keywords: Anteromedial knee OA; Oxford UKA; Patient-reported outcome measures; Total knee arthroplasty.